A method for setting the roll shape of a finishing mill without roll shifting device

Abstract

This invention provides a method for setting the roll shape of a finishing mill without a roll shifting device, comprising: when changing support rolls in any finishing mill in the finishing mill production line, configuring one standby support roll and multiple standby work rolls for the finishing mill; determining the maximum and minimum converted roll diameter values ​​and the target converted roll diameter value based on the theoretically designed maximum and minimum support roll diameters, maximum and minimum work roll diameters, and the roll diameters of the standby support roll and standby work rolls; calculating the target work roll shape corresponding to the standby work roll; grinding the standby work roll according to the target work roll shape corresponding to the standby work roll; during the operation of the standby support roll, rotating the multiple standby work rolls at preset time intervals, and re-grinding the standby work rolls rotated off the finishing mill during the operation of the standby support roll according to the target work roll shape corresponding to the multiple standby work rolls, so as to continue to rotate and use them during the operation of the support roll.

Description

Technical Field

[0001] This invention relates to the field of steel rolling technology, and in particular to a method for setting the roll shape of a finishing mill without a roll shifting device. Background Technology

[0002] Some hot strip mill finishing mills are six-stand continuous rolling mills without roll shifting capabilities. Furthermore, the roll bending function was added later, with an effective adjustment range of only 25 to 100 tons for the bending force. The support rolls are flat rolls, and the work rolls are conventional flat rolls (generally concave). Daily shape control relies mainly on the combination of the bending rolls and the original work roll shape, with minor adjustments to the rolling load distribution for fine-tuning. This results in limited shape control. The inventors discovered that after replacing the finishing mill support rolls, the rolling line frequently experiences severe central or bilateral waviness upon resuming production. Due to the lack of roll shifting capabilities and weak roll bending control, the waviness cannot be eliminated, making continued production impossible. Emergency shutdowns are required to modify the work roll shape, and sometimes a single modification is insufficient, necessitating two more modifications. This severely impacts the quality of the rolled steel plates, and shutdowns for roll shape modification significantly reduce production efficiency.

[0003] In the process of developing this invention, the applicant discovered at least the following problems in the prior art:

[0004] Finishing mills without roll shifting function and with weak roll bending control often experience severe central or bilateral waviness after production resumes following the replacement of finishing mill support rolls. This seriously affects the quality of rolled steel plates, and downtime for roll shape modification impacts production efficiency. Summary of the Invention

[0005] This invention provides a method for setting the roll shape of a finishing mill without a roll shifting device, a method for processing the roll shape of a finishing mill without a roll shifting device, and a method for adjusting the roll shape of a finishing mill without a roll shifting device. This addresses the problem that finishing mills with weak roll shifting functionality and bending roll control capabilities often experience severe central or bilateral waviness after resuming production following the replacement of finishing mill support rolls, which seriously affects the quality of rolled steel plates. The need to stop the mill to modify the roll shape also impacts production efficiency.

[0006] To achieve the above objectives, in one aspect, embodiments of the present invention provide a method for setting the roll shape of a finishing mill without roll shifting devices, comprising:

[0007] When changing the support roll of any finishing mill in the finishing mill production line, one standby support roll and multiple standby work rolls are configured for the finishing mill;

[0008] Based on the maximum support roll diameter and the maximum work roll diameter of the finishing mill's theoretical design, determine the maximum equivalent roll diameter value; based on the minimum support roll diameter and the minimum work roll diameter of the finishing mill's theoretical design, determine the minimum equivalent roll diameter value; based on the roll diameter of the support roll to be used and the roll diameters corresponding to the plurality of work rolls to be used, determine the target equivalent roll diameter value.

[0009] The target work roll shape corresponding to the plurality of work rolls to be used is calculated according to the following formula (1):

[0010]

[0011] Where A is the target working roll shape, in micrometers; d max The maximum converted roller diameter is expressed in millimeters; d min d represents the minimum equivalent roll diameter in millimeters; d represents the target equivalent roll diameter in millimeters; A min The minimum limiting roll shape of the work rolls used when the finishing mill employs the support rolls and work rolls with the theoretically designed minimum roll diameter, in micrometers; A max The maximum limiting roll shape of the work rolls used when the finishing mill employs the support rolls and work rolls with the theoretically designed maximum roll diameter, in micrometers;

[0012] Grind the plurality of work rolls according to the target work roll shape corresponding to the plurality of work rolls to be used;

[0013] During the operation of the standby support roll, the plurality of standby work rolls are used in rotation at preset time intervals. For the standby work rolls rotated off the finishing mill during the operation of the standby support roll, the rotated standby work rolls are re-ground according to the target work roll shape corresponding to the plurality of standby work rolls, so that they can be used in rotation during the operation of the support roll.

[0014] The target working roll shape is the amount by which the diameter of the middle part of the grinding working roll is smaller than the diameter of the end part.

[0015] Wherein, the maximum equivalent roll diameter is the equivalent roll diameter value corresponding to the moment of inertia of the overall roll system consisting of the work roll and support roll with the theoretically designed maximum roll diameter of the finishing mill, converted into a single unit; the minimum equivalent roll diameter is the equivalent roll diameter value corresponding to the equivalent roll diameter of the overall roll system consisting of the work roll and support roll with the theoretically designed minimum roll diameter of the finishing mill, converted into a single unit; the target equivalent roll diameter value is the equivalent roll diameter value corresponding to the equivalent roll diameter value corresponding to the moment of inertia of the overall roll system consisting of the work roll and support roll to be used, converted into a single unit; the work roll to be used is used to replace the finishing mill when changing the work roll and / or support roll. The currently used work rolls on the rolling mill; the standby support rolls are used to replace the currently used support rolls on the finishing mill when the finishing mill changes support rolls; the minimum limiting roll shape is the work roll shape corresponding to the work rolls of the finishing mill, under the target constraint that the plate shape after finishing is a flat plate shape in the current production, and when the finishing mill uses support rolls and work rolls with the theoretically designed minimum roll diameter; the maximum limiting roll shape is the work roll shape corresponding to the work rolls of the finishing mill, under the target constraint that the plate shape after finishing is a flat plate shape in the current production, and when the finishing mill uses support rolls and work rolls with the theoretically designed maximum roll diameter. The work roll shape is the amount by which the diameter of the middle part of the ground work roll is smaller than the diameter of the end part.

[0016] Further, determining the maximum converted roll diameter value based on the maximum support roll diameter and the maximum work roll diameter of the finishing mill, according to the theoretical design, includes:

[0017] Input the maximum support roll diameter and the maximum work roll diameter of the theoretically designed finishing mill into the following formula (2) to obtain the maximum converted roll diameter value;

[0018]

[0019] Where, d max The maximum converted roller diameter is expressed in millimeters; d 支max The maximum support roll diameter of the finishing mill, in millimeters; d 工max The maximum theoretically designed work roll diameter for the finishing mill, in millimeters (μ). max This is the preset conversion factor when calculating the maximum converted roll diameter.

[0020] Further, determining the minimum equivalent roll diameter value based on the minimum support roll diameter and minimum work roll diameter theoretically designed for the finishing mill includes:

[0021] Input the minimum support roll diameter and minimum work roll diameter of the theoretically designed finishing mill into the following formula (3) to obtain the minimum converted roll diameter value;

[0022]

[0023] Where, d min The minimum equivalent roller diameter, in millimeters; d 支min The minimum support roll diameter, in millimeters, is the theoretically designed diameter of the finishing mill; d 工min The minimum working roll diameter theoretically designed for the finishing mill, in millimeters (μ). min This is the preset conversion factor when calculating the minimum converted roll diameter.

[0024] Further, determining the target converted roller diameter value based on the roller diameter of the support roller to be used and the roller diameters corresponding to the plurality of work rollers to be used includes:

[0025] The average value of the roller diameters of multiple work rolls to be used is taken as the roller diameter corresponding to the multiple work rolls to be used. The roller diameters of the support roller to be used and the roller diameters corresponding to the multiple work rolls to be used are input into the following formula (4) to obtain the target converted roller diameter value.

[0026]

[0027] Where d is the calculated diameter of the roll to be used, in millimeters; 支 d represents the diameter of the support roller to be used, in millimeters. 工 , where is the diameter of the multiple work rolls to be used, in millimeters; μ is the preset conversion factor when calculating the target converted roll diameter value.

[0028] Furthermore, the range of preset conversion factors for calculating the maximum converted roll diameter, the minimum converted roll diameter, and the target converted roll diameter includes: arrive

[0029] Furthermore, the preset conversion factors for the maximum converted roll diameter, the minimum converted roll diameter, and the target converted roll diameter are calculated as follows:

[0030] Furthermore, the minimum and maximum limit roll shapes are negative values, and the absolute values ​​of the minimum and maximum limit roll shapes of the upstream finishing mill in the finishing mill production line are respectively less than the absolute values ​​of the minimum and maximum limit roll shapes of the downstream finishing mill.

[0031] Furthermore, the finishing mill production line includes a 6-stand continuous finishing mill; the minimum limiting roll shape of the 1st to 3rd mills counting from the upstream side of the finishing mill production line is -100 micrometers and the maximum limiting roll shape is -30 micrometers, and the minimum limiting roll shape of the 4th to 6th finishing mills is -130 micrometers and the maximum limiting roll shape is -60 micrometers.

[0032] Furthermore, the formulas for calculating the working roll shape of the working roll to be used, as well as the formulas for calculating the maximum equivalent roll diameter, the minimum equivalent roll diameter, and the target equivalent roll diameter, are edited into a computer program. When using the program, the roll diameter of the support roll to be used and the roll diameter corresponding to the working roll to be used are input to obtain the target working roll shape corresponding to the working roll to be used.

[0033] Furthermore, the finishing mill production line includes six continuously rolling finishing mills; the sixth finishing mill, starting from the upstream side of the finishing mill production line, has a maximum support roll diameter of 1524 mm, a minimum support roll diameter of 1374 mm, a maximum work roll diameter of 754 mm, a minimum work roll diameter of 681 mm, a minimum limiting roll shape of -130 micrometers, a maximum limiting roll shape of -60 micrometers, a maximum equivalent roll diameter of 1712.5 mm, and a minimum equivalent roll diameter of 1544.25 mm;

[0034] The work roll shape of the sixth finishing mill stand, starting from the upstream side of the finishing mill production line, is calculated according to the following formula (5):

[0035]

[0036] Where A6 represents the work roll profile of the sixth finishing mill, in micrometers; d 支6 This indicates the diameter of the standby support rolls for the sixth finishing mill, in millimeters; d 工6 This indicates the diameter of the ready-to-use work rolls for the sixth finishing mill, in millimeters.

[0037] The above technical solution has the following beneficial effects: By calculating the converted roll diameter and combining the maximum and minimum roll shape, a simple linear correspondence is used to calculate the roll shape of the work roll to be used for advance roll shape modification. Before replacing the support roll, based on the new support roll and work roll diameter data, a reasonable work roll shape is pre-calculated, and the roll shape modification amount is transmitted to the roll grinding operation area in advance. The grinding parameters are modified to obtain the new work roll shape. Then, the new support roll is replaced and production is resumed, and the new roll shape can be matched and used for steel rolling production. This effectively improves the plate shape control stability of the finishing mill with weak roll cutting and bending capabilities. After testing, after using the embodiment of the present invention, there were no more serious double-sided waves or central waves caused by roll shape mismatch after replacing the support roll. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a flowchart of a finishing mill roll shape setting method for a roll-free device, which is one embodiment of the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] On the one hand, such as Figure 1 As shown, an embodiment of the present invention provides a method for setting the roll shape of a finishing mill without roll shifting, comprising:

[0042] Step S10: When changing the support roll in any finishing mill in the finishing mill production line, configure one standby support roll and multiple standby work rolls for the finishing mill.

[0043] Step S11: Determine the maximum equivalent roll diameter value based on the maximum support roll diameter and the maximum work roll diameter of the finishing mill's theoretical design; determine the minimum equivalent roll diameter value based on the minimum support roll diameter and the minimum work roll diameter of the finishing mill's theoretical design; and determine the target equivalent roll diameter value based on the roll diameter of the support roll to be used and the roll diameters corresponding to the plurality of work rolls to be used.

[0044] Step S12: Calculate the target working roll shape corresponding to the plurality of working rolls to be used according to formula (1);

[0045] Step S13: Grind the plurality of work rolls to be used according to the target work roll shape corresponding to the plurality of work rolls to be used;

[0046] Step S14: During the operation of the standby support roll, the plurality of standby work rolls are used in rotation at preset time intervals. For the standby work rolls rotated off the finishing mill during the operation of the standby support roll, the rotated standby work rolls are re-ground according to the target work roll shape corresponding to the plurality of standby work rolls, so that they can be used in rotation during the operation of the support roll.

[0047] The target working roll shape is the amount by which the diameter of the middle part of the grinding working roll is smaller than the diameter of the end part.

[0048] The maximum converted roll diameter value is based on the moment of inertia of a cylindrical object's cross-section, aiming to convert the moment of inertia of the entire roll system consisting of the theoretically designed maximum-diameter work roll and the maximum-diameter support roll of the finishing mill into a single unit. It is a roll diameter value calculated from the theoretically designed maximum-diameter work roll and the maximum-diameter support roll. The minimum converted roll diameter value is also based on the moment of inertia of a cylindrical object's cross-section, aiming to convert the moment of inertia of the entire roll system consisting of the theoretically designed minimum-diameter work roll and the minimum-diameter support roll of the finishing mill into a single unit. It is a roll diameter value calculated from the theoretically designed minimum-diameter work roll and the minimum-diameter support roll. The target converted roll diameter value is based on the moment of inertia of a cylindrical object's cross-section, aiming to convert the moment of inertia of the entire roll system consisting of the unused work roll and the unused support roll into a single unit. With the goal of integration, a roll diameter value is calculated from the roll diameter of the support roll to be used and the roll diameter of the work roll to be used; the work roll to be used is used to replace the work roll currently used on the finishing mill when the work roll and / or support roll are changed; the support roll to be used is used to replace the support roll currently used on the finishing mill when the support roll is changed; the minimum limit roll shape is the work roll shape corresponding to the work roll of the finishing mill under the target constraint that the plate shape after finishing is a flat plate shape in the current production, and when the support roll and work roll of the finishing mill are matched with the theoretically designed minimum roll diameter; the maximum limit roll shape is the work roll shape corresponding to the work roll of the finishing mill under the target constraint that the plate shape after finishing is a flat plate shape in the current production, and when the support roll and work roll of the finishing mill are matched with the theoretically designed maximum roll diameter.

[0049] In some embodiments, the replacement cycles of the support rolls and work rolls of a finishing mill are typically different. Generally, the replacement cycle of the standby support rolls is significantly longer than that of the standby work rolls. Therefore, during the operation of the same standby support roll, multiple standby work rolls need to be rotated at preset time intervals. The replacement cycle of the support rolls in a finishing mill is relatively long, for example, once a month, while the replacement cycle of the work rolls is shorter, typically with a preset time interval of several hours, for example, 2 to 3 hours. During the operation of a standby support roll, the standby work rolls are replaced multiple times. Each time a (standby) support roll is replaced, multiple (standby) work rolls are provided to that (standby) support roll, and these paired standby work rolls are rotated during the operation of that standby support roll. Each finishing mill specifies a standard theoretically designed maximum roll diameter, minimum roll diameter, maximum roll diameter of the support rolls, and minimum roll diameter of the support rolls. When replacing support rolls, it is necessary to determine the available support rolls and multiple work rolls to be used, based on the availability of spare support rolls and work rolls on the finishing mill production line and the grinding capacity of the grinding workshop. The multiple work rolls to be used must have the same diameter, or the deviation between their diameters must be within a preset tolerance range, preferably -10 mm to 10 mm. Traditionally, after selecting support rolls and work rolls, the rolled steel sheet must be observed directly on the finishing mill before disassembly and grinding. This process involves repeated measurements and grinding to finally obtain support rolls and work rolls that meet the required operating conditions. This traditional approach consumes a significant amount of time each time support rolls are replaced, severely reducing efficiency. This invention avoids repeated measurements and grinding by pre-calculating the target work roll dimensions of multiple work rolls to be used with the support roll and completing the grinding before use. This improves the replacement efficiency of support rolls and work rolls. The principle behind converting the moment of inertia of the entire roll system (considered as the maximum diameter, minimum diameter, or standby) consisting of the work roll and the corresponding support roll (considered as the maximum diameter, minimum diameter, or standby) into a single unit is based on the calculation method for the moment of inertia of a cylindrical cross-section. Since the neck dimensions, bearing housing dimensions, and roll body length of the support and work rolls are fixed, and only the roll body diameter changes each time, a simple calculation method can be used to ignore the influence of the neck and bearing housing, considering only the change in roll body diameter. In the calculation of roll deflection, the change in roll diameter mainly affects the moment of inertia of the roll body. Therefore, by simply measuring the change in the roll's moment of inertia, a simple correlation between the roll diameter and roll shape can be roughly deduced. The formula for calculating the moment of inertia of a cylindrical object's cross-section is:

[0050]

[0051] Where I is the moment of inertia of the cross section, in mm. 4 (millimeters to the power of 4); D is the diameter of the cylindrical object, measured in millimeters.

[0052] According to the above formula (6), the moment of inertia of the cross section is proportional to the fourth power of the diameter. Therefore, when the moment of inertia of the overall roll system consisting of the theoretically largest diameter work roll, the theoretically smallest diameter work roll, and the work roll to be used, respectively, are converted into a whole, the maximum converted roll diameter value, the minimum converted roll diameter value, and the work roll to be used can be determined by the ratio of the theoretically largest diameter work roll, the theoretically smallest diameter work roll, and the work roll to be used relative to the theoretically largest diameter support roll, the theoretically smallest diameter support roll, and the work roll to be used. The minimum and maximum limit roll shape can be obtained by actual measurement. In production, each finishing mill is preset with a corresponding load reduction. Combined with the fact that the roll diameters of the support rolls and work rolls theoretically designed for each finishing mill may be the same or different between each finishing mill, the minimum and maximum limit roll shape values ​​corresponding to different finishing mills may be the same or different. When measuring the minimum limit roll shape, for each finishing mill stand, the support rolls and work rolls with the minimum roll diameter theoretically designed for the finishing mill are used. The slab is finished rolled according to the load reduction required by the current production requirements. The work roll shape of the work rolls is adjusted according to the actual shape of the slab after finishing rolling until the shape of the finished slab is a straight shape. The work roll shape of the work rolls at this time is the minimum limit roll shape. When measuring the maximum limit roll shape, for each finishing mill stand, the support rolls and work rolls with the maximum roll diameter theoretically designed for the finishing mill are used. The slab is finished rolled according to the load reduction required by the current production requirements. The work roll shape of the work rolls is adjusted according to the actual shape of the slab after finishing rolling until the shape of the finished slab is a straight shape. The work roll shape of the work rolls at this time is the maximum limit roll shape.

[0053] The embodiments of this invention have the following beneficial effects: By calculating the converted roll diameter and combining the maximum and minimum roll shape amounts, a simple linear correspondence is used to calculate the roll shape amount of the work roll to be used for advance roll shape modification. Before replacing the support roll, based on the new support roll and work roll diameter data, a reasonable work roll shape amount is pre-calculated, and the roll shape modification amount is transmitted to the roll grinding operation area in advance. The grinding parameters are modified to obtain the new work roll shape, and then the new support roll is replaced to resume production. The new roll shape can then be matched and used for steel rolling production, effectively improving the shape control stability of the finishing mill with weak roll cutting and bending capabilities. After testing, after using the embodiments of this invention, there were no more serious double-sided waves or central waves caused by roll shape mismatch after replacing the support roll.

[0054] Further, determining the maximum converted roll diameter value based on the maximum support roll diameter and the maximum work roll diameter of the finishing mill, according to the theoretical design, includes:

[0055] Input the maximum support roll diameter and the maximum work roll diameter of the theoretically designed finishing mill into formula (2) to obtain the maximum converted roll diameter value.

[0056] In some embodiments, the maximum converted roll diameter value is obtained by converting the moment of inertia of the support roll and the work roll with the maximum roll diameter of the theoretically designed maximum roll diameter into one using formula (2). Since the roll neck size, bearing seat size, roll body length, etc. of the support roll and the work roll are fixed, and only the roll body diameter changes each time, a simple calculation method can be used to ignore the influence of the roll neck and bearing seat and only consider the change of the roll body diameter. In the calculation of the roll deflection, the change of the roll diameter mainly affects the moment of inertia of the roll body. Therefore, it is only necessary to calculate the change of the roll moment of inertia to roughly deduce the simple relationship between the roll diameter and the roll shape. The formula for calculating the moment of inertia of the cross section of a cylindrical object is formula (6); according to the above formula (6), the moment of inertia of the cross section is proportional to the fourth power of the diameter; preferably, the preset conversion coefficient μ when calculating the maximum converted roll diameter value is used. max The ratio of the maximum diameter of the work roll to the maximum diameter of the support roll in the theoretical design of the finishing mill can be taken as the fourth power. Considering the direct contact between the work roll and the steel plate, the adjustment of the bending force, and the influence of the work roll's moment of inertia on the actual site conditions, μ is determined. max The value of μ can be greater than or equal to the fourth power of the ratio of the maximum diameter of the work roll to the maximum diameter of the support roll in the theoretical design of the finishing mill. Preferably, μ can also be the value obtained by multiplying the fourth power of the ratio of the maximum diameter of the work roll to the maximum diameter of the support roll in the theoretical design of the finishing mill by 4. max The value of μ. Since the ratio of the maximum diameter of the work rolls to the maximum diameter of the support rolls in the theoretical design of each finishing mill in the same finishing production line is not significantly different, therefore, preferably, μ max The value of the fourth power of the approximate ratio of the maximum diameter of the work roll to the maximum diameter of the support roll in the theoretical design of each finishing mill in the entire finishing rolling production line can be used. Taking into account the direct contact between the work roll and the steel plate, the adjustment of the bending force, and other factors, and considering the site conditions, the influence of the work roll's moment of inertia can be determined. max The value of μ can be greater than or equal to the fourth power of the approximate ratio of the maximum theoretically designed work roll diameter to the maximum support roll diameter of each finishing mill in the entire finishing mill production line. Preferably, μ can also be obtained by multiplying the fourth power of the approximate ratio of the maximum theoretically designed work roll diameter to the maximum support roll diameter of each finishing mill in the entire finishing mill production line by 4. maxThe value of . The method for determining the approximate ratio of the maximum roll diameter of the theoretically designed work rolls of each finishing mill in the entire finishing mill production line to the maximum roll diameter of the support rolls includes, but is not limited to, dividing the average value of the maximum roll diameter of the theoretically designed work rolls of each finishing mill in the entire finishing mill production line by the average value of the maximum roll diameter of the support rolls, or dividing the median value of the maximum roll diameter of the theoretically designed work rolls of each finishing mill by the median value of the maximum roll diameter of the support rolls, etc.

[0057] The embodiments of this invention have the following technical effects: They innovatively link the work roll profile with the changes in the diameters of the support roll and work roll. The main reason for the severe double-sided and center-sided waviness that easily occurs after replacing the finishing mill support roll is that the change in the diameters of the support roll and work roll leads to changes in the rigidity of the roll system. Under the same load, the deflection deformation of the roll system differs, the actual roll gap shape of the work roll changes, and the mismatch between the front and rear stand profiles exceeds the control range, resulting in severe waviness. Based on this problem, the embodiments of this invention pre-calculate and modify the new work roll profile to match the replaced support roll when replacing the support roll. Based on the moment of inertia of the cylindrical section and the actual site conditions, a calculated roll diameter value that can characterize the rigidity of the entire roll system of support rolls and work rolls is designed.

[0058] Further, determining the minimum equivalent roll diameter value based on the minimum support roll diameter and minimum work roll diameter theoretically designed for the finishing mill includes:

[0059] Input the minimum support roll diameter and minimum work roll diameter of the theoretically designed finishing mill into formula (3) to obtain the minimum converted roll diameter value.

[0060] In some embodiments, the minimum converted roll diameter value is obtained by converting the moment of inertia of the support roll and the work roll with the minimum roll diameter of the theoretically designed minimum roll diameter into one by formula (3). Since the roll neck size, bearing seat size, roll body length, etc. of the support roll and the work roll are fixed, and only the roll body diameter changes each time, a simple calculation method can be used to ignore the influence of the roll neck and bearing seat and only consider the change of the roll body diameter. In the calculation of the roll deflection, the change of the roll diameter mainly affects the moment of inertia of the roll body. Therefore, it is only necessary to calculate the change of the roll moment of inertia to roughly deduce the simple relationship between the roll diameter and the roll shape. The formula for calculating the moment of inertia of the cross section of a cylindrical object is formula (6). According to the above formula (6), the moment of inertia of the cross section is proportional to the fourth power of the diameter; preferably, the preset conversion coefficient μ when calculating the minimum converted roll diameter value is used. min The ratio of the minimum diameter of the work roll to the minimum diameter of the support roll in the theoretical design of the finishing mill can be taken as the fourth power. Considering the direct contact between the work roll and the steel plate, the adjustment of the bending force, and the influence of the work roll's moment of inertia on the actual site conditions, μ is determined. minThe value of μ can be greater than or equal to the fourth power of the ratio of the minimum diameter of the work roll to the minimum diameter of the support roll in the theoretical design of the finishing mill. Preferably, μ can also be obtained by multiplying the fourth power of the ratio of the minimum diameter of the work roll to the minimum diameter of the support roll in the theoretical design of the finishing mill by 4. min The value of μ. Since the ratio of the minimum roll diameter of the work roll to the minimum roll diameter of the support roll in the theoretical design of each finishing mill in the same finishing production line is not significantly different, it is preferable that μ min The approximate fourth power of the ratio of the minimum roll diameter of the work roll to the minimum roll diameter of the support roll in the theoretical design of each finishing mill in the entire finishing rolling production line can be used. Considering the direct contact between the work roll and the steel plate, as well as the adjustment of the bending force and other factors, and taking into account the site conditions, the influence of the work roll's moment of inertia, μ, can be determined. min The value of μ can be greater than or equal to the fourth power of the approximate ratio of the minimum theoretical design work roll diameter to the minimum support roll diameter of each finishing mill in the entire finishing mill production line. Preferably, μ can also be obtained by multiplying the fourth power of the approximate ratio of the minimum theoretical design work roll diameter to the minimum support roll diameter of each finishing mill in the entire finishing mill production line by 4. min The value of . The method for determining the approximate ratio of the minimum roll diameter of the theoretically designed work rolls of each finishing mill to the minimum roll diameter of the support rolls includes, but is not limited to, dividing the average value of the minimum roll diameter of the theoretically designed work rolls of each finishing mill in the entire finishing mill production line by the average value of the minimum roll diameter of the support rolls, or dividing the median value of the minimum roll diameter of the theoretically designed work rolls of each finishing mill by the median value of the minimum roll diameter of the support rolls, etc.

[0061] The embodiments of this invention have the following technical effects: They innovatively link the work roll profile with the changes in the diameters of the support roll and work roll. The main reason for the severe double-sided and center-sided waviness that easily occurs after replacing the finishing mill support roll is that the change in the diameters of the support roll and work roll leads to changes in the rigidity of the roll system. Under the same load, the deflection deformation of the roll system differs, the actual roll gap shape of the work roll changes, and the mismatch between the front and rear stand profiles exceeds the control range, resulting in severe waviness. Based on this problem, the embodiments of this invention pre-calculate and modify the new work roll profile to match the replaced support roll when replacing the support roll. Based on the moment of inertia of the cylindrical section and the actual site conditions, a calculated roll diameter value that can characterize the rigidity of the entire roll system of support rolls and work rolls is designed.

[0062] Further, determining the target converted roller diameter value based on the roller diameter of the support roller to be used and the roller diameters corresponding to the plurality of work rollers to be used includes:

[0063] The average value of the diameters of multiple working rolls to be used is taken as the diameter of the multiple working rolls to be used. The diameters of the support rolls to be used and the diameters of the multiple working rolls to be used are input into formula (4) to obtain the target converted roll diameter value.

[0064] In some embodiments, the moment of inertia of the support roll and the work roll to be used is converted into a single value using formula (4) to obtain the converted roll diameter value. Since the neck size, bearing seat size, and roll body length of the support roll and the work roll are fixed, and only the roll body diameter changes each time, a simple calculation method can be used to ignore the influence of the neck and bearing seat and only consider the change of the roll body diameter. In the calculation of the roll deflection, the change of the roll diameter mainly affects the moment of inertia of the roll body. Therefore, it is only necessary to calculate the change of the roll's moment of inertia to roughly deduce the simple relationship between the roll diameter and the roll shape. The formula for calculating the moment of inertia of a cylindrical object is formula (6). According to the above formula (6), the moment of inertia of the cross section is proportional to the fourth power of the diameter; preferably, the preset conversion coefficient μ when calculating the target converted roll diameter value can be taken as the fourth power of the ratio of the work roll diameter to the support roll diameter. Considering the direct contact between the work roll and the steel plate, the adjustment of bending force, and the influence of the moment of inertia of the work roll determined by the site conditions, the value of μ can be greater than or equal to the fourth power of the ratio of the diameter of the work roll to the diameter of the support roll. Preferably, μ can also be obtained by multiplying the fourth power of the ratio of the diameter of the work roll to the diameter of the support roll by 4. Since the diameter ratios of each work roll relative to each support roll in the same finishing mill production line are not significantly different, μ can preferably be the fourth power of the approximate ratio of the diameters of the work rolls to the support rolls used in the entire finishing mill production line. Considering the direct contact between the work roll and the steel plate, the adjustment of bending force, and the influence of the moment of inertia of the work roll determined by the site conditions, the value of μ can be greater than or equal to the fourth power of the approximate ratio of the diameters of the work rolls to the support rolls used in the entire finishing mill production line. Preferably, μ can also be obtained by multiplying the fourth power of the approximate ratio of the diameters of the work rolls to the support rolls used in the entire finishing mill production line by 4. Methods for determining the approximate ratio of the working roll diameter to the support roll diameter include, but are not limited to, dividing the average working roll diameter by the average support roll diameter, or dividing the median working roll diameter by the median support roll diameter.

[0065] The embodiments of this invention have the following technical effects: They innovatively link the work roll profile with the changes in the diameters of the support roll and work roll. The main reason for the severe double-sided and center-sided waviness that easily occurs after replacing the finishing mill support roll is that the change in the diameters of the support roll and work roll leads to changes in the rigidity of the roll system. Under the same load, the deflection deformation of the roll system differs, the actual roll gap shape of the work roll changes, and the mismatch between the front and rear stand profiles exceeds the control range, resulting in severe waviness. Based on this problem, the embodiments of this invention pre-calculate and modify the new work roll profile to match the replaced support roll when replacing the support roll. Based on the moment of inertia of the cylindrical section and the actual site conditions, a calculated roll diameter value that can characterize the rigidity of the entire roll system of support rolls and work rolls is designed.

[0066] Preferably, the range of preset conversion factors for calculating the maximum converted roll diameter, the minimum converted roll diameter, and the target converted roll diameter includes: arrive

[0067] Preferably, the preset conversion factors for calculating the maximum converted roll diameter, the minimum converted roll diameter, and the target converted roll diameter are as follows:

[0068]

[0069] In some embodiments, the moments of inertia of the support roller and the work roller are considered as a single unit. The diameter of the work roller in this production line is approximately half that of the support roller; therefore, the calculated moment of inertia of the work roller is approximately 1 / 16 of that of the support roller. Considering the direct contact between the work roller and the steel plate, the adjustment of the bending force, and other factors, and taking into account the site conditions, the influence of the work roller's moment of inertia is determined. A preset conversion factor μ is used to convert the work roller diameter, where μ is greater than or equal to 1 / 16.

[0070] The embodiments of this invention have the following technical effects: They innovatively link the work roll profile with the changes in the diameters of the support roll and work roll. The main reason for the severe double-sided and center-sided waviness that easily occurs after replacing the finishing mill support roll is that the change in the diameters of the support roll and work roll leads to changes in the rigidity of the roll system. Under the same load, the deflection deformation of the roll system differs, the actual roll gap shape of the work roll changes, and the mismatch between the front and rear stand profiles exceeds the control range, resulting in severe waviness. Based on this problem, the embodiments of this invention pre-calculate and modify the new work roll profile to match the replaced support roll when replacing the support roll. Based on the moment of inertia of the cylindrical section and the actual site conditions, a calculated roll diameter value that can characterize the rigidity of the entire roll system of support rolls and work rolls is designed.

[0071] Furthermore, the minimum and maximum limit roll shapes are negative values, and the absolute values ​​of the minimum and maximum limit roll shapes of the upstream finishing mill in the finishing mill production line are respectively less than the absolute values ​​of the minimum and maximum limit roll shapes of the downstream finishing mill.

[0072] Preferably, the finishing mill production line includes a 6-stand continuous finishing mill; the minimum limiting roll shape of the 1st to 3rd mills counting from the upstream side of the finishing mill production line is -100 micrometers and the maximum limiting roll shape is -30 micrometers, and the minimum limiting roll shape of the 4th to 6th finishing mills is -130 micrometers and the maximum limiting roll shape is -60 micrometers.

[0073] In some embodiments, in a finishing mill production line with multiple finishing mills connected in series, the upstream finishing mill typically bears a larger load distribution, heavier load, and greater roll deflection compared to the downstream finishing mills. Therefore, the initial roll shape design of the upstream finishing mill is slightly smaller. Preferably, all six stands of the finishing mill are controlled according to the above method. The front-end mill F1-3 has a larger load distribution, heavier load, and greater roll deflection compared to the F4-6 mills, so its initial roll shape design is slightly smaller. The front-end mill F1-3 also needs to undergo multiple roll shape adjustment tests to consider crown control, ultimately determining the ultimate roll shape amount A of the F1-3 mill. max =-30um, A min = -100um, determine the limiting roll shape A of F4-6 rolling mill. max =-60um, A min =-130um, the support rolls and work rolls of all rolling mills are universal, and the maximum and minimum roll diameter values ​​are consistent. All rolling mill data is edited into the computer; only the support roll diameter and work roll diameter need to be input to output the matching work roll shape. Technicians can fine-tune and modify the calculated roll shape based on experience. Preferably, the finishing mill production line is specifically configured as a hot continuous rolling mill with a six-stand continuous rolling mill, no roll shifting function, and an effective controllable range of 25 tons to 100 tons for the bending force; the support rolls are flat rolls.

[0074] Furthermore, the formulas for calculating the target working roll shape of the working roll to be used, as well as the formulas for calculating the maximum equivalent roll diameter, the minimum equivalent roll diameter, and the target equivalent roll diameter, are edited into a computer program. When using the program, the roll diameter of the support roll to be used and the roll diameter corresponding to the working roll to be used are input to obtain the target working roll shape corresponding to the working roll to be used.

[0075] In some embodiments, this roll shape calculation method is programmed into a computer. Each time the support roll is replaced, only the diameters of the support roll and the work roll need to be input into the computer to calculate the matching roll shape. Furthermore, historical roll shape data can be saved and recorded. Before replacing the support roll, technicians input the new support roll and work roll diameter data into the computer, pre-calculating a reasonable work roll shape. The roll shape modification amount is then transmitted to the roll grinding area in advance, and the grinding parameters are modified to obtain the new work roll shape. Upon replacement of the new support roll and resumption of production, the new roll shape can be used for steel rolling, effectively improving the shape control stability of finishing mills with weak roll cutting and bending capabilities, and increasing replacement efficiency.

[0076] Furthermore, the finishing mill production line includes six continuously rolling finishing mills; the sixth finishing mill, starting from the upstream side of the finishing mill production line, has a maximum support roll diameter of 1524 mm, a minimum support roll diameter of 1374 mm, a maximum work roll diameter of 754 mm, a minimum work roll diameter of 681 mm, a minimum limiting roll shape of -130 micrometers, a maximum limiting roll shape of -60 micrometers, a maximum equivalent roll diameter of 1712.5 mm, and a minimum equivalent roll diameter of 1544.25 mm;

[0077] The working roll shape of the sixth finishing mill from the upstream side of the finishing mill production line is calculated according to the following formula (6).

[0078] The embodiments of this invention have the following beneficial effects: The equivalent roll diameter value, representing the rigidity of the entire roll system of support rolls and work rolls, is determined based on the moment of inertia of the cylindrical cross-section. By calculating the equivalent roll diameter and combining the maximum and minimum roll shape measurements, a simple linear correspondence is used to calculate the roll shape of the work roll to be used for advance roll shape modification. Before replacing the support roll, a reasonable work roll shape measurement is pre-calculated based on the new roll diameter data of the support roll and work roll to be used. The roll shape modification amount is then transferred to the roll grinding operation area in advance, and the grinding parameters are modified to obtain the new roll shape of the work roll to be used. After replacing the support roll and resuming production, the new roll shape can be matched and used for steel rolling production. This effectively improves the shape control stability of finishing mills with weak roll bending and cutting capabilities. Testing shows that after using the embodiments of this invention, there are no longer serious double-sided or central waves caused by roll shape mismatch after replacing the support roll. The embodiments of this invention specifically provide a calculation formula for the roll shape of the work roll of the sixth finishing mill in a six-stand continuous rolling mill, facilitating program execution in production.

[0079] The technical solutions of the present invention will be described in detail below with reference to specific application examples. For technical details not described in the implementation process, please refer to the relevant descriptions above.

[0080] This invention relates to the field of steel rolling technology and is mainly aimed at hot continuous rolling mill finishing mills without roll shifting function. Specifically, it calculates a more reasonable roll shape based on the changes in the diameter of the finishing mill support roll and the work roll, and adjusts and controls the roll shape in advance to avoid serious double-sided or central waves after the support roll is replaced, which would affect product quality and production stability.

[0081] The purpose of this invention is to overcome the shortcomings of the prior art and to achieve a method of pre-calculating a reasonable roll shape before replacing the finishing mill support roll and adjusting it in advance to match the new working conditions, thereby avoiding the losses caused by the lag in making emergency roll shape adjustments after the appearance of waviness.

[0082] Long-term on-site monitoring revealed that waviness issues after replacing support rolls in the finishing mill always occurred when there were significant changes in the diameters of both the support rolls and the work rolls. Further analysis showed that the changes in the diameters of the support rolls and work rolls altered the rigidity of the roll system. Under the same load during rolling, the varying deflection of the work rolls resulted in different actual work roll gap shapes, making it impossible to achieve proper matching of the front and rear stand profiles and leading to severe waviness problems. When the roll diameter increased, the roll rigidity increased, resulting in smaller roll deflection under the same load, equivalent to a smaller actual roll gap concavity, making medium-sized waviness more likely. Conversely, when the roll diameter decreased, the roll rigidity decreased, resulting in larger roll deflection under the same load, equivalent to a larger actual roll gap concavity, making double-sided waviness more likely.

[0083] Therefore, the roll profile of the work roll needs to be adjusted in a timely manner to match the changes in the diameters of the support roll and the work roll. Since actual production control on the steel rolling mill is complex and influenced by many factors, it is considered to use on-site experience to set the roll profile of the work roll.

[0084] Based on long-term field tracking, the work roll profile value that achieves a flat plate effect when the smallest diameter support roll is matched with the smallest diameter work roll is determined to be A. min The roll profile of the work roll that achieves a flat plate shape when the support roll with the largest diameter is matched with the work roll with the largest diameter is determined to be A. max .

[0085] Since the neck size, bearing housing size, and roll body length of the support roll and work roll are fixed, and only the roll body diameter changes each time, a simple calculation method can be used to ignore the influence of the neck and bearing housing and only consider the change in the roll body diameter.

[0086] In the calculation of roll deflection, the change in roll diameter mainly affects the moment of inertia of the roll body. Therefore, by simply measuring the change in the moment of inertia of the roll, a simple relationship between the roll diameter and the roll shape can be roughly deduced.

[0087] The formula for calculating the moment of inertia of a cylindrical object is formula (6).

[0088] The moments of inertia of the support roller and the work roller are considered as one. The diameter of the work roller in this production line is about 1 / 2 of that of the support roller. Therefore, the calculated moment of inertia of the work roller is about 1 / 16 of that of the support roller. However, considering that the work roller is in direct contact with the steel plate and the bending force is controlled, and combined with the site conditions, the influence of the moment of inertia of the work roller is increased to 1 / 4. Therefore, the converted support roller diameter of the work roller is determined to be 1 / 4 of the work roller diameter.

[0089] The formulas for calculating the converted roll diameter are formulas (2), (3), and (4), with the maximum converted roll diameter d as the starting point. max Corresponding to maximum roll shape A max Using the minimum calculated roller diameter d minCorresponding minimum roll shape A min The roller shape and the equivalent roller diameter adopt the phenomenon correspondence law (that is, the larger the equivalent roller diameter, the larger the roller shape needs to be matched, and the smaller the equivalent roller diameter, the smaller the roller shape needs to be matched). The working roller shape is calculated based on the support roller diameter and the working roller diameter. The specific calculation formula for the working roller shape is formula (1).

[0090] Taking the F6 stand (the 6th finishing mill) of a production line consisting of 6 finishing mills as an example, after multiple roll shape modification tests and comparative tracking, A was determined. max = -60um (micrometer), A min = -130um, the maximum and minimum working and support roll diameters. The maximum working roll diameter, maximum support roll diameter, minimum working roll diameter, and minimum support roll diameter are designed for the rolling mill equipment configuration. The new rolls (working rolls and support rolls) have the maximum roll diameter. After a period of use, they are replaced and ground on a grinding machine for reuse. Each time they are ground, the roll diameter will decrease. When the roll diameter of the working rolls and support rolls reaches the minimum roll diameter after repeated grinding and replacement, they can no longer be used. At this time, the rolls will be scrapped and no longer used.

[0091] The calculated maximum and minimum equivalent roller diameters are shown in Table 1.

[0092] Minimum working roll 681mm Maximum working roll 754mm Minimum support roller 1374mm Maximum support roller 1524mm Minimum roller diameter conversion 1544.25mm Maximum roller diameter conversion 1712.5mm

[0093] Table 1 shows the roll diameter data for the F6 stand, and the real-time work roll shape is as follows:

[0094]

[0095] Where A6 is the working roll profile of the 6th finishing mill stand, in micrometers; d6 is the equivalent roll diameter of the 6th finishing mill stand, in millimeters; d 支6 The diameter of the standby support rolls for the 6th finishing mill is shown in millimeters; d 工6 The diameter of the ready-to-use work rolls for the 6th finishing mill is in millimeters.

[0096] By editing this calculation formula into the computer, and inputting the diameters of the new support roller and the new work roller in advance each time the support roller is replaced, a more suitable work roller shape can be calculated. The work roller shape can be modified in advance to match the new support roller and work roller, ensuring the stability of the plate shape quality after production resumes.

[0097] All six stands of the finishing mill were controlled using the above method. The front-end mill F1-3 had a larger load distribution and load compared to F4-6, resulting in greater roll deflection; therefore, the initial roll shape design was slightly smaller. Multiple roll shape adjustment tests were conducted on the front-end mill F1-3, taking crown control into account, to ultimately determine the ultimate roll shape value A for F1-3. max=-30um, A min = -100um, determine the limiting roll shape A of F4-6 rolling mill. max =-60um, A min = -130um, common to both support rolls and work rolls of all rolling mills, with consistent maximum and minimum roll diameter values. All rolling mill data is edited into the computer; only the support roll diameter and work roll diameter need to be input to output the matching work roll shape. Technicians can fine-tune and modify the calculated roll shape based on experience. Table 2 is the input roll diameter table, and Table 3 is the corresponding output work roll shape table. Table 2 lists the roll diameters input for each of the six finishing mills when the support rolls and work rolls were replaced on June 15th, July 15th, and August 15th; Table 3 gives the work roll shape of the work rolls for each finishing mill.

[0098]

[0099] Table 2 is the input roller diameter table.

[0100]

[0101] Table 3 is the output work roll shape table.

[0102] The embodiments of the present invention have the following technical effects:

[0103] This invention innovatively links the work roll profile to changes in the diameters of the support roll and work roll. It identifies the primary cause of severe double-sided and center-sided waviness after replacing the finishing mill support roll: changes in the diameters of the support roll and work roll lead to variations in the rigidity of the roll system. Under the same load, the roll system exhibits different deflection deformations, resulting in changes in the actual roll gap shape of the work roll. Furthermore, the mismatch between the front and rear stand shape exceeds the control range, leading to severe waviness. Based on this problem, an embodiment of the invention is implemented, where the profile of the new work roll is pre-calculated and modified to match the replaced support roll when replacing the support roll. A calculated roll diameter value, characterizing the rigidity of the entire roll system (support roll and work roll), is designed based on the moment of inertia of the cylindrical section and actual field conditions. Through long-term field tracking and roll profile test comparisons, the work roll profile value A that ensures good plate shape for each rolling mill under the maximum and minimum calculated roll diameters is summarized. max and A minMeanwhile, the front-end mill F1-3 also considers crown control requirements. A method was developed to calculate the appropriate roll shape based on changes in the support roll and work roll. By calculating the converted roll diameter and combining the maximum and minimum roll shape measurements, a simple linear correspondence is used to calculate the real-time work roll shape measurement for advance roll shape modification. This roll shape calculation method is programmed into a computer; each time the support roll is changed, only the support roll and work roll diameters need to be input into the computer to calculate the matching roll shape measurement. Furthermore, historical roll shape measurement data can be saved and recorded. Before replacing the support rolls, technicians input the new support roll and work roll diameter data into the computer, which can pre-calculate the reasonable work roll shape and transmit the roll shape modification amount to the roll grinding operation area in advance. The grinding parameters are then modified to obtain the new work roll shape. After replacing the new support rolls and resuming production, the new roll shape can be matched and used for steel rolling production. This effectively improves the plate shape control stability of finishing mills with weak roll cutting and bending capabilities. After testing, the use of this embodiment of the invention has not resulted in severe double-sided waves or central waves caused by roll shape mismatch after replacing the support rolls.

[0104] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the scope to the specific order or hierarchy described.

[0105] In the above detailed description, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features of the single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, wherein each claim stands alone as a preferred embodiment of the invention.

[0106] The disclosed embodiments have been described above to enable any person skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit and scope of this disclosure. Therefore, this disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0107] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations falling within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is used in a manner similar to the term "including." Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

[0108] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for setting the roll shape of a finishing mill without roll shifting devices, characterized in that, include: When changing the support roll of any finishing mill in the finishing mill production line, one standby support roll and multiple standby work rolls are configured for the finishing mill; Based on the maximum support roll diameter and the maximum work roll diameter of the finishing mill's theoretical design, determine the maximum equivalent roll diameter value; based on the minimum support roll diameter and the minimum work roll diameter of the finishing mill's theoretical design, determine the minimum equivalent roll diameter value; based on the roll diameter of the support roll to be used and the roll diameters corresponding to the plurality of work rolls to be used, determine the target equivalent roll diameter value. The target work roll shape corresponding to the plurality of work rolls to be used is calculated according to the following formula; in, It is the target working roll shape measurement, in micrometers; This is the maximum converted roller diameter value, in millimeters; This is the minimum equivalent roller diameter value, in millimeters; Calculate the target roller diameter value in millimeters; The minimum limiting roll shape of the work roll used when the finishing mill employs the support roll and work roll with the theoretically designed minimum roll diameter, in micrometers; The maximum limiting roll shape of the work rolls used when the finishing mill employs the support rolls and work rolls with the theoretically designed maximum roll diameter, in micrometers; Grind the plurality of work rolls according to the target work roll shape corresponding to the plurality of work rolls to be used; During the operation of the standby support roll, the plurality of standby work rolls are used in rotation at preset time intervals. For the standby work rolls rotated off the finishing mill during the operation of the standby support roll, the rotated standby work rolls are re-ground according to the target work roll shape corresponding to the plurality of standby work rolls, so that they can be used in rotation during the operation of the standby support roll. The target working roll shape is the amount by which the diameter of the middle part of the grinding working roll is smaller than the diameter of the end part.

2. The method for setting the roll shape of a finishing mill with a roll-free device as described in claim 1, characterized in that, The determination of the maximum converted roll diameter value based on the maximum support roll diameter and the maximum work roll diameter of the finishing mill, according to the theoretical design, includes: Input the maximum support roll diameter and the maximum work roll diameter of the theoretically designed finishing mill into the following formula to obtain the maximum converted roll diameter value; ,in, This is the maximum converted roller diameter value, in millimeters; The maximum support roll diameter of the finishing mill, in millimeters; The maximum working roll diameter, in millimeters, is the theoretically designed diameter of the finishing mill. This is the preset conversion factor when calculating the maximum converted roll diameter.

3. The method for setting the roll shape of a finishing mill with a roll-off-free device as described in claim 1, characterized in that, The determination of the minimum converted roll diameter value based on the minimum support roll diameter and minimum work roll diameter designed according to the finishing mill includes: Input the minimum support roll diameter and minimum work roll diameter of the theoretically designed finishing mill into the following formula to obtain the minimum converted roll diameter value; ,in, This is the minimum equivalent roller diameter value, in millimeters; The minimum support roll diameter, in millimeters, is the theoretically designed diameter of the finishing mill. The minimum working roll diameter, in millimeters, is the theoretically designed diameter of the finishing mill. This is the preset conversion factor when calculating the minimum converted roll diameter.

4. The method for setting the roll shape of a finishing mill with a roll-off-free device as described in claim 1, characterized in that, The step of determining the target converted roller diameter value based on the roller diameter of the support roller to be used and the roller diameters corresponding to the plurality of work rollers to be used includes: The average value of the roller diameters of multiple work rolls to be used is taken as the roller diameter corresponding to the multiple work rolls to be used. The roller diameter of the support roller to be used and the roller diameter corresponding to the multiple work rolls to be used are input into the following formula to obtain the target converted roller diameter value. in, The value is the calculated roller diameter to be used, in millimeters; The diameter of the support roller to be used is in millimeters; The diameter of the plurality of work rolls to be used is given in millimeters. The preset conversion factor for calculating the target converted roll diameter value.

5. The method for setting the roll shape of a finishing mill with a roll-free device as described in claim 2, 3, or 4, characterized in that, The range of preset conversion factors for calculating the maximum converted roll diameter, minimum converted roll diameter, and target converted roll diameter is as follows: arrive .

6. The method for setting the roll shape of a finishing mill with a roll-off-free device as described in claim 5, characterized in that, The preset conversion factors for calculating the maximum converted roll diameter, minimum converted roll diameter, and target converted roll diameter are as follows: .

7. The method for setting the roll shape of a finishing mill with a roll-off-free device as described in claim 1, characterized in that, The minimum and maximum roll shape values ​​are negative, and the absolute values ​​of the minimum and maximum roll shape values ​​of the upstream finishing mill in the finishing mill production line are respectively less than the absolute values ​​of the minimum and maximum roll shape values ​​of the downstream finishing mill.

8. The method for setting the roll shape of a finishing mill with a roll-free device as described in claim 7, characterized in that, The finishing mill production line includes a 6-stand continuous finishing mill; the minimum limiting roll shape of the 1st to 3rd mills, starting from the upstream side of the finishing mill production line, is -100 micrometers and the maximum limiting roll shape is -30 micrometers; the minimum limiting roll shape of the 4th to 6th finishing mills is -130 micrometers and the maximum limiting roll shape is -60 micrometers.

9. The method for setting the roll shape of a finishing mill with a roll-free device as described in claim 1, characterized in that, The formulas for calculating the target working roll shape of the working roll to be used, as well as the formulas for calculating the maximum equivalent roll diameter, minimum equivalent roll diameter, and target equivalent roll diameter, are edited into a computer program. When using the program, the roll diameter of the support roll to be used and the roll diameter corresponding to the working roll to be used are input to obtain the target working roll shape of the working roll to be used.

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