Four-high reversible plate mill rigidity calculation model and application thereof

Abstract

A four high reversible plate mill rigidity calculation model and application. It includes the following specific measures: collecting the rigidity data of the mill; establishing the rigidity calculation model of the mill; exploring the rigidity change law of the mill; constructing the rigidity stability evaluation system of the mill; analyzing the rigidity data of the mill and the actual application; formulating and optimizing the equipment gap management; and realizing the rigidity automatic compensation in the rolling process. The beneficial effects of the present application are: effectively narrowing the raw edge width of the finished product thickness steel plate, effectively improving the comprehensive benefits; improving the camber of the steel plate, on the one hand, the rolling rhythm can be improved, and the rolling waste can be reduced, on the other hand, the centering efficiency of the disc shear can be improved, the shear camber can be reduced, the edge serration and the meat tumor can be reduced, the edge quality of the steel plate can be improved, and the present application has high indirect economic benefits and social benefits.

Description

TECHNICAL FIELD

[0001] The present application relates to a rolling mill stiffness control system, in particular to a four-roll reversible plate mill stiffness calculation model and application. BACKGROUND

[0002] With the continuous good market of plate, accelerating the production capacity has become the focus of the work of the plate mill at this stage, and tapping the potential of equipment and accelerating the release of production capacity has encountered a bottleneck. The control of the rectangular degree of the steel plate after rolling has been a key indicator restricting the yield and quality of the plate mill, and the stiffness of the rolling mill is the source of a series of key quality indicators of the finished product such as stable rolling of the steel plate and plate shape quality. Through the stiffness test of the rolling mill, it is found that the stiffness of the two sides of the rolling mill is very different when the rolling mill is rotated forward and backward. The maximum stiffness difference when rotating forward is-8.15%, and the maximum stiffness when rotating backward is 13.85%. Moreover, the stiffness of the same working roll is different in different rolling periods, and the maximum stiffness change can reach 7.26%. The large stiffness difference causes the operator to rely on the naked eye to observe the plate shape and adjust the pressure on both sides during rolling different passes. At the same time, due to the limitation of naked eye observation, the intervention effect is not ideal, resulting in obvious camber of the steel plate. SUMMARY

[0003] The purpose of the present application is to overcome the shortcomings and defects in the prior art, and to provide a four-roll reversible plate mill stiffness calculation model and application, which effectively narrows the raw edge width of the finished product thickness and effectively improves the comprehensive benefits. The improvement of the camber of the steel plate can improve the rolling rhythm and reduce the rolling waste, and can improve the centering efficiency of the disc shear, reduce the shear camber, reduce the edge serration and the tumor, improve the edge quality of the steel plate, and has high indirect economic benefits and social benefits.

[0004] To achieve the above purpose, the following technical scheme is adopted: a four-roll reversible plate mill stiffness calculation model and application, which includes the following specific measures: rolling mill stiffness data acquisition; establishment of rolling mill stiffness calculation model; exploration of rolling mill stiffness change rule; construction of rolling mill stiffness stability evaluation system; rolling mill stiffness data analysis and practical application; S6, development and optimization of equipment gap management; realization of rolling process stiffness automatic compensation.

[0005] Further, the rolling mill stiffness data acquisition specifically adds a rolling mill stiffness automatic acquisition function to the rolling mill zero setting interface to avoid errors caused by manual operation.

[0006] Further, the establishment of the rolling mill stiffness calculation model specifically includes a roll elastic deformation calculation model, a rolling mill stand elastic deformation calculation model, a pressure reduction system elastic deformation calculation model, an other load-bearing component elastic deformation calculation model, and a roll cross elastic deformation calculation model.

[0007] Further, the establishment of the rolling mill stiffness calculation model is specifically: according to the springback curve of the rolling mill, when the rolling force is less than a certain value, the elastic deformation of the rolling mill and the rolling force are in a nonlinear relationship, which is mainly caused by the contact deformation, uneven contact and bearing gap between parts, and when the rolling force is greater than the value, the elastic deformation of the rolling mill and the rolling force are approximately linear, so in the production process, it is often treated as linear.

[0008] Further, the exploration of the rolling mill stiffness variation law specifically includes the rolling mill stiffness variation law in the working roll rolling period, the rolling mill stiffness variation law under different step pad thicknesses, and the rolling mill stiffness variation law in different roll diameters.

[0009] Further, the construction of the rolling mill stiffness stability evaluation system is specifically: according to the Young's modulus and the rolling mill springback equation, the elastic deformation of the rolling mill under the rolling force is calculated by measuring the roll, the rack, the screwdown system, the supporting roll bearing seat, the screwdown screw pad, the thrust spherical pad, the lower roll system elevation pad, and the roll cross equivalent convexity, and the rolling mill stiffness model is based on the data.

[0010] Further, the measures taken for formulating and optimizing the equipment gap management are as follows: step pad classification management to ensure similar hardness in the same gear; adding step pad elevation measurement reference to ensure the rolling line elevation; independently designing measurement tools to improve the accuracy management of the spherical pad; replacing the nylon lining plate to improve the stability of the working roll system on the machine; and perfecting the rolling mill stand gap management to realize narrow width control.

[0011] After adopting the above technical scheme, the present application has the following beneficial effects:

[0012] 1. The steel plate raw edge width of the finished product thickness is effectively narrowed, and the comprehensive benefits are effectively improved.

[0013] 2. The steel plate camber is improved, which can improve the rolling rhythm, reduce rolling waste, improve the centering efficiency of the disc shear, reduce the shear camber, reduce the edge serration and the meat tumor, improve the edge quality of the steel plate, and has high indirect economic benefits and social benefits. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0015] Figure 1 It is a wrong figure in the present application.

[0016] Figure 2 is the accurate rigidity data collection chart in the application.

[0017] Figure 3 is the rigidity difference chart of two sides in the rolling cycle in the application.

[0018] Figure 4 is the rigidity difference chart of positive and negative rotation in the rolling cycle in the application.

[0019] Figure 5 is the step pad thickness and rolling mill rigidity curve chart in the application.

[0020] Figure 6 is the rigidity influence situation chart of the rolling cycle of the roll in the application.

[0021] Figure 7 is the rolling mill rigidity model measurement interface chart in the application.

[0022] Figure 8 is the rolling mill rigidity curve chart in the application.

[0023] Figure 9 is the rolling mill rigidity change trend chart in the application.

[0024] Figure 10 is the rolling mill rigidity change trend chart in the application.

[0025] Figure 11 is the relative rigidity difference statistical chart of two sides of the rolling mill before and after the research in the application. DETAILED DESCRIPTION

[0026] The technical solution adopted in the detailed description is as follows:

[0027] S1, rolling mill rigidity data collection:

[0028] In the early stage, due to insufficient understanding of rigidity, the rigidity analysis is performed through the curve data during the rolling mill zero adjustment, which leads to large deviation between the rolling mill rigidity analysis result and the actual production. After many experiments, it is finally determined to collect the rolling mill PDA data under the conditions of uniform rotation (10 rad / min) and pressure, as shown in FIG. 1. Figures 1-2

[0029] Meanwhile, the rolling mill rigidity automatic collection function is added to the rolling mill zero adjustment interface, so as to avoid the rolling mill rigidity data collection error caused by different manual operations.

[0030] S2, establishment of rolling mill rigidity calculation model:

[0031] ​In the rolling process, the rolling mill stiffness can be considered as the ability of the rolling mill to resist plastic deformation of the rolled piece, that is, the amount of elastic deformation of the rolling mill. The total elastic deformation of the rolling mill includes the elastic deformation of the rack, the lower roll elevation system, the roll system, the supporting roll bearing seat and the compressed parts of the screwdown screw and nut, the screwdown screw and nut, and other rolling mill components.

[0032] According to the springback curve of the rolling mill, when the rolling force is less than a certain value, the elastic deformation of the rolling mill and the rolling force are in a nonlinear relationship, which is mainly caused by the contact deformation, uneven contact and bearing gap between the parts. When the rolling force is greater than the value, the elastic deformation of the rolling mill and the rolling force are approximately linear, so it is often treated as linear in the production process.

[0033] The slope K is the stiffness coefficient of the rolling mill: In the formula: K is the stiffness coefficient of the rolling mill, with the unit of kN / mm; ΔP is the rolling force change of the straight line part of the springback curve, with the unit of kN; ΔL is the elastic deformation of the rolling mill in the straight line part of the springback curve, with the unit of mm.

[0034] The physical meaning of the stiffness coefficient of the rolling mill is that the rolling force required to produce 1mm of elastic deformation of the rolling mill represents the ability of the rolling mill to resist elastic deformation. The larger the stiffness coefficient of the rolling mill, the less the elastic deformation of the rolling mill, and the better the stiffness.

[0035] According to the definition of Young's modulus: In the formula: E is the elastic modulus, GPa=kN / mm 2 ; K is the elastic coefficient or stiffness, with the unit of kN; L is the length of the material, with the unit of mm 2 ;

[0036] From the slope K and Young's modulus, the total stiffness of the rolling mill has the following relationship with each part of the rolling mill, that is, the total stiffness of the rolling mill can be calculated by calculating the elastic deformation or stiffness of each part:

[0037] The elastic deformation of each component of the rolling mill is calculated, and the stiffness of the rolling mill is calculated. The total elastic deformation F of the rolling mill is: In the formula: F is the total elastic deformation of the rolling mill, including the elastic deformation of the roll F1, the rack F2, the screwdown system F3, the supporting roll bearing seat F4, the screwdown screw pad F5, the thrust spherical pad F6, the lower roll system elevation pad (including the supporting roll lower pressure pad, the step pad, the pressure bearing pad, the base) F7, the equivalent convexity of the roll cross F8, and other parts.

[0038] Furthermore, the established mill stiffness calculation model includes the calculation model of roll elastic deformation, the calculation model of mill stand elastic deformation, the calculation model of rolling system elastic deformation, the calculation model of other loaded components elastic deformation, and the calculation model of roll cross elastic deformation.

[0039] 1) Calculation model for elastic deformation of rolls: The elastic deformation F1 of the rolls includes the bending deformation δ1 in the middle of the support roll body and the elastic flattening δ between the support roll and the work roll. bw The elastic flattening δ of the work roll ww That is: F1=2δ1+2δ bw +2δ ww In the formula, δ1 is the deflection of the support roller, including the deflection δ1 caused by the bending moment and the deflection δ1 caused by the shear force, that is: δ1=δ z1 +δ z2 The elastic deformation formulas for each component are as follows: In the formula: P is the rolling force, kN; Eb is the elastic modulus of the support roll; Db is the diameter of the support roll, in mm; a is the distance between the center lines of the support roll bearings, in mm; Lb is the length of the support roll body, in mm; c is the distance from the point of application of the support reaction force to the edge of the roll, in mm; d is the diameter of the support roll, in mm.

[0040] In the formula: Gb is the shear modulus of the support roller, in GPa;

[0041] In the formula: θ is a coefficient related to the roll material. GPa -1 ; Poisson's ratio of the two roll materials, dimensionless; E w E b q represents the elastic modulus of the two roll materials, in GPa; q represents the unit load acting on the work roll body, in kN / mm; q = P / L w Where p is the rolling force, kN; L w Dw is the length of the work roll body, in mm; Db is the diameter of the work roll, in mm; Db is the diameter of the support roll, in mm. Combining these, we get:

[0042] 2) Calculation Model for Elastic Deformation of Rolling Mill Stand: The elastic deformation of the stand consists of the bending deformation of the crossbeams and the tensile deformation of the columns. Since the cross-sectional dimensions of the crossbeams are relatively large compared to their length, the influence of shear force should be considered when calculating the bending deformation of the crossbeams. That is, the bending deformation F2 of the crossbeams caused by bending moment and shear force. a and F2 b and the column deformation F2 caused by tension. c That is: F2 = F2a +F2 b +F2 c

[0043] The deformation calculation formula of the beam and column of the rolling mill stand is as follows: In the formula, L1 is the length of the neutral axis (center line) of the beam of the stand, in mm; E is the elastic modulus of the material of the stand, I1 is the moment of inertia of the upper beam of the stand, in mm4; R0 is the force on the beam, for a steel plate rolling mill, R0 is generally taken as half of the rolling force P, i.e. R0 = P / 2; M2 is the moment of force in the column of the stand, in kN·mm; L2 is the length of the neutral axis (neutral line) of the column of the stand, in mm; I2 is the moment of inertia of the column of the stand, in mm4.

[0044] In the formula, K is the sectional shape coefficient of the beam, for a rectangular section, the coefficient K is 1.2; G is the shear elastic modulus of the material of the stand, in GPa; F1 is the sectional area of the beam, in mm 2 .

[0045] In the formula, F1 is the sectional area of the column, in mm 2 .

[0046] 3) The elastic deformation calculation model of the screwdown system: for the electric screwdown device, the elastic deformation affecting the rolling mill includes the compression deformation F3 a of the screwdown nut, the compression deformation F3 b of the screw and the bending deformation F3 c of the screw thread, i.e.

[0047] In the formula, R0 is the load on the nut, in kN; t is the pitch, in mm; D is the outer diameter of the nut, in mm; d0 is the inner diameter of the nut, in mm; d2 is the diameter of the non-threaded part at the end of the screw, in mm; E T , E s are the elastic moduli of the materials of the nut and the screw, in GPa; d m is the pitch diameter of the screw thread, in mm; L3, L4 are the lengths of the extended part of the screw and the non-threaded part at the end of the screw, in mm; L5 is the height of the nut, in mm.

[0048] 4) The elastic deformation calculation model of other loaded parts: the bearing seat of the backup roll F4, the gasket of the screw F5, the gasket of the thrust ball F6, the gasket of the elevation of the lower roll system F7 and other parts also produce compression deformation during rolling. In the formula, R0 is the force of the loaded part, in kN; h​j is the calculated height of the force-bearing part of the bearing seat, in mm; E0 is the elastic modulus of the bearing seat, in GPa; F p is the average cross-sectional area of the force-bearing part of the bearing seat, in mm 2 ; h d is the height of the force-bearing part of the backing plate, in mm; E d is the area of the force-bearing part of the backing plate, in mm 2 ; F p is the elastic modulus of the backing plate, in GPa; h q is the height of the spherical pad, in mm; D q is the diameter of the spherical pad, in mm; E q is the elastic modulus of the spherical pad, in GPa. L j , S j , E j are the height, cross-sectional area and elastic modulus of the supporting roller lower pressing pad, step pad, pressure pad and base, respectively, in mm, mm 2 , GPa

[0049] 5) Rolling mill cross elastic deformation calculation model: the cross elastic deformation of the rolling mill is calculated by calculating the equivalent convexity F8 of the rolling mill, and under the action of the force R0. The calculation formula of the equivalent convexity is as follows: In the formula: L is 1 / 2 of the length of the rolling mill body, in mm; is the intersection angle between the rolling mill and the axis, in °; D is the rolling mill roll diameter, in mm;

[0050] In the formula: I a is the deflection arc length of the rolling mill, in mm; r is the center distance of the rolling mill bearing seat, in mm.

[0051] S3, explore the change law of rolling mill stiffness: including the change law of rolling mill stiffness in the rolling period of the work roll, the change law of rolling mill stiffness under different step pad thicknesses, and the change law of rolling mill stiffness under different rolling mill roll diameters:

[0052] Change law of rolling mill stiffness in the rolling period of the work roll: by measuring the stiffness values of the three work rolls in different rolling periods, the stiffness difference of the two sides and the forward and reverse rotation of the rolling mill is calculated, the roll 1 equipment is normal, and the step pads of the roll 2 and roll 3 have cracking problems, as shown in Figures 3-4

[0053] ​The rigidity of roller 1 is poor and unstable in the early stage of rolling, affected by the scale, oil stains and other factors, with a fluctuation of about 2.6%, while the rigidity tends to be stable afterwards, with a fluctuation of about 0.95%. The rigidity of roller 2 and roller 3 fluctuates greatly at any stage, with a maximum of 9.38%. It can be seen that if the gasket has quality problems such as cracking, it will cause a large difference in the elastic deformation of each side or the positive and negative rotation process when the rolling mill is under stress, and the difference has no regularity, thereby seriously affecting the stability of the rigidity of the rolling mill.

[0054] 2) Change rule of rolling mill rigidity under different stepped gasket thicknesses: When replacing the roller, the height of the stepped gasket is usually adjusted according to the roller diameter. When the height of the stepped gasket is 110-170 mm, as shown in Figure 5 , the rigidity of the rolling mill decreases linearly with the increase of the height of the stepped gasket, and the total rigidity decreases by 0.34%. Generally, the adjustment of the height of the stepped gasket is symmetrical on both sides, so the change of the rigidity on both sides also changes together, and the influence on the rigidity difference can be basically ignored.

[0055] 3) Change rule of rolling mill rigidity under different roller diameters: When the service life of the work roller and the supporting roller is 940-1000 mm and 1650-1800 mm respectively, as shown in Figure 6 , the service life of the work roller has little effect on the total rigidity of the rolling mill, and only increases the total rigidity of the rolling mill by 0.067% at the end. In the service life of the supporting roller, the rigidity of the rolling mill decreases with the decrease of the roller diameter, and decreases by 6.35% at the end of the service life of the supporting roller. The decrease of the work roller and the supporting roller is nonlinear with the decrease of the rigidity of the rolling mill.

[0056] The main reason why the diameter of the supporting roller has a great influence on the rigidity of the rolling mill is that the supporting roller produces bending deformation under the action of the rolling force, and the bending deformation is nonlinear with the change of the rolling force. For example, when the rolling force is 36000 kN and the diameter of the supporting roller is 1800 mm, the total deflection of the upper and lower supporting rollers is 0.825 mm, and when the diameter of the supporting roller is 1650 mm, the total deflection is 1.113 mm. The influence of the deflection of the supporting roller on the rigidity reaches 5.23%.

[0057] S4, construction of rolling mill rigidity stability evaluation system: According to the Young's modulus and the rolling mill elastic deformation equation, the elastic deformation of the main categories of the rolling mill under the action of the rolling force is calculated, including the roller, the rack, the screw-down system, the supporting roller bearing seat, the screw-down screw gasket, the thrust spherical gasket, the lower roller system height gasket (supporting roller lower pressure gasket, stepped gasket, pressure bearing gasket, base), and the equivalent convexity of the roller intersection, which totals 8, and the rolling mill rigidity model is shown in Figure 7 .

[0058] Based on the rolling mill model, a related stability evaluation system is established, such as:

[0059] 1) When the stiffness difference of both sides and positive and reverse rotation is less than 5%, it can be considered that the effect of rolling mill stiffness on production is small, and the target should be controlled to be less than 4% of the rolling mill stiffness difference;

[0060] 2) The effect of rolling force on rolling mill stiffness can be considered as a small near-range effect and a large far-range effect, that is, when the rolling force difference of both sides or positive and reverse rotation is small, it can be considered that the rolling force basically does not affect the stiffness;

[0061] 3) The integrity of the stepped pad is concerned (including whether it is cracked and deformed), and the thickness difference of the pad on both sides is not too large;

[0062] 4) The use cycle of the work roll has a small effect on the total stiffness of the rolling mill, while the backup roll has a large effect;

[0063] 5) The rolling mill gap should be particularly concerned about whether it will cause the roll cross, and the cross amount should be estimated, because the effect of the roll cross on the stiffness is not too large when the roll cross is small, but the roll cross will greatly increase with the increase of the cross degree;

[0064] S5, rolling mill stiffness data analysis and actual application: according to the actual measured rolling mill stiffness and rolling mill stiffness model analysis, when the positive rotation, the additional elastic deformation is generated on the roll changing side, which causes the stiffness to decrease to 3147kN / mm; when the reverse rotation, the additional elastic deformation is generated on the transmission side, which causes the stiffness to decrease to 3107kN / mm, the additional elastic deformation causes the rolling mill stiffness to decrease by 8-12%, as shown in Figure 8 Table 1.

[0065]

[0066]

[0067] Table 1: Rolling mill stiffness value table

[0068] At the same time, according to the stiffness curve measured many times, it can be seen that the stability of the rolling mill stiffness is very poor, the stiffness difference is from 0.91% to 15.15%, and the fluctuation is large, so it can be judged that the lower roll system elevation is cracked, which causes the additional elastic deformation of the roll system in the longitudinal and transverse directions, and causes the stiffness to decrease, as shown in Figure 9 .

[0069] According to the actual measured rolling mill stiffness and rolling mill stiffness model analysis, the additional elastic deformation is generated on the transmission side when the positive rotation and the reverse rotation, which causes the stiffness of the transmission side to decrease, and the additional elastic deformation causes the rolling mill stiffness to decrease by 6.84%-9.81%. And according to the measurement many times, the rolling mill stiffness decrease is generally not more than 10%, so it is judged that the equipment gap is large. The measured gap of the upper bending roll cylinder of the transmission side is 4.5mm, after adding the pad, the rolling mill stiffness is normal, asFigure 10 and shown in Table 2 below:

[0070] Turning Turning side Roll change side Relative difference Forward rotation 3559 3811 -6.84％ Reverse rotation 3440 3795 -9.81％ Relative difference 3.40％ 0.42％

[0071] Table 2: Rolling mill stiffness change table

[0072] S6, Formulate and optimize equipment gap management: According to the stiffness model, the main factors affecting the stiffness of the rolling mill are the elevation of the lower roller system and the cross of the roller system, which causes additional longitudinal and transverse elastic deformation of the rolling mill, thereby reducing the stiffness of the rolling mill. The main measures taken are as follows:

[0073] 1) Classified management of stepped pads to ensure similar hardness in the same gear:

[0074] Check the hardness and appearance size of all stepped pad spare parts one by one, divide the stepped pads into four grades according to hardness: <HRC32, HRC32≤X<HRC40, HRC40≤X<HRC48 and >HRC48, and use them according to the similar hardness in the same grade to avoid the situation of inconsistent stiffness on both sides.

[0075] 2) Add stepped pad elevation measurement reference to ensure rolling line elevation:

[0076] Add stepped pad elevation measurement reference, take the force-free crossbeam at the bottom of the rolling mill body as the reference, compare it with the stepped pad calibration parameters, determine the wear of the pressure pad, add stepped pad elevation measurement on the north and south sides of the empty slot, judge the overall situation of the pressure pad, and ensure the stability of the rolling mill.

[0077] 3) Independently design measurement tools to improve the precision management of spherical pads:

[0078] The spherical pad is installed below the bearing seat on both sides of the lower support roller and directly contacts the stepped pad of the rolling mill. Since the stepped pad is a circular arc surface, it is difficult to measure the precision. Based on this, by studying the precision requirements of the spherical pad processing drawings, an arc surface measurement method is independently designed to detect the wear degree of the circular arc surface, thereby ensuring the stability of the rolling mill.

[0079] 4) Replace the nylon lining plate to improve the stability of the work roller system on the machine:

[0080] The nylon lining plate is made of elastic material, which can fully reduce the equipment gap and impact load, thereby improving the stability of the rolling mill.

[0081] 5) Improve the gap management of the rolling mill stand and achieve narrow control:

[0082] Re-adjust the important gap tolerances of the rolling mill support roller, work roller lining plate, etc., and comprehensively narrow all lining plate gaps that contact the rolling mill stand, thereby providing a basis for fine management of the rolling mill gap.

[0083] S7, realizing the rolling process stiffness automatic compensation: based on the rolling mill model to establish the relevant stability evaluation system, add "stiffness difference compensation" function on the finishing rolling HMI control interface, the lower display rolling mill stiffness model calculation compensation roll gap pass specific data.

[0084] The effectiveness of the rolling mill stiffness difference compensation model is verified, and the relevant stability evaluation system of the rolling mill model is evaluated. By rolling different steel grades and different specifications with and without stiffness difference compensation, the transverse same plate difference and finished plate shape of the steel plate are counted as shown in the following table. From the statistical situation, the plate shape with stiffness difference compensation is better than that without stiffness difference compensation, and the transverse same plate difference of the steel plate is significantly reduced (see Table 3).

[0085]

[0086] Table 3: Steel plate transverse same plate difference and plate shape tracking statistics

[0087] Through the above measures, the number of manual intervention correction times for producing thin gauge steel plates in 2021 gradually decreased, especially the average inclination intervention of single steel plate with thickness of 8-10mm was ≤5 times, accounting for 91.25% (see Table 4), and the difficulty of plate shape control was greatly reduced.

[0088]

[0089]

[0090] Table 4: Statistics table of the number of steel plates rolled ≤10mm and the total number of rolling process intervention times in different periods

[0091] The relative difference of the stiffness of the rolling mill on both sides before and after the research is shown in Figure 11 .

[0092] From the above Figure 11 As can be seen from Table 4, through the research of the medium plate plant, the relative difference of the stiffness of the rolling mill gradually decreases, the relative stiffness difference and the positive and negative stiffness difference of the rolling mill on both sides are both <6%, and are stably within ≤3%, reaching the research target of (6% below), and the effect is remarkable.

[0093] The above description is only to illustrate the technical solutions of the present application, not to limit, other modifications or equivalent replacements of the technical solutions of the present application made by those skilled in the art should be covered in the scope of the claims of the present application, as long as they do not depart from the spirit and scope of the technical solutions of the present application.

Claims

1. An application method for a stiffness calculation model of a four-roll reversible medium-thick plate rolling mill, characterized in that: It includes the following specific measures: S1, Collection of mill stiffness data; S2, Establish a calculation model for the stiffness of the rolling mill; S3, Investigating the variation law of rolling mill stiffness; S4, Construct a rolling mill stiffness and stability assessment system; S5, Rolling Mill Stiffness Data Analysis and Practical Application; S6, Develop and optimize equipment clearance management; S7 enables automatic stiffness compensation during the rolling process; S2 specifically includes the calculation model of elastic deformation of the rolls, the calculation model of elastic deformation of the mill stand, the calculation model of elastic deformation of the pressing system, the calculation model of elastic deformation of other load-bearing components, and the calculation model of elastic deformation of the roll cross. Other load-bearing components are the support roll bearing seat, the pressing screw pad, the thrust ball pad, and the lower roll system elevation pad. S3 specifically includes the variation law of mill stiffness within the rolling cycle of the work roll, the variation law of mill stiffness under different step pad thicknesses, and the variation law of mill stiffness within different roll diameters. Specifically, S4 involves: based on Young's modulus and the mill bounce equation, calculating the elastic deformation of eight main categories of the mill under rolling force, including rolls, stands, reduction system, support roll bearing housing, reduction screw pads, thrust ball pads, lower roll system elevation pads, and roll cross equivalent crown. Using this as the basis, a mill stiffness model is established, and a relevant stability assessment system is built based on the mill model. The specific measures taken by S6 are as follows: 1) Classify and manage stepped mats to ensure that the hardness of mats in the same grade is similar; 2) Add a new benchmark for measuring the elevation of the stepped pads to ensure the elevation of the rolling line; 3) Independently design measuring tools to improve the accuracy management of spherical mats; 4) Replace the nylon liner to improve the stability of the work roller system on the machine; 5) Improve the management of the gap between the rolling mill stands to achieve narrow-range control.

2. The application method of the stiffness calculation model of a four-roll reversible medium-thick plate rolling mill according to claim 1, characterized in that: Specifically, S1 adds an automatic mill stiffness acquisition function to the mill zeroing interface to avoid mill stiffness data acquisition errors caused by different manual operations.

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