CVC roller control method and system for hot rolled strip steel

Abstract

The invention relates to the field of hot-rolled plate strip steel rolling plate shape control, and discloses a CVC roller control method and system for hot-rolled plate strip steel, specifically, detailed grading calculation is carried out according to the width and thickness of the strip steel, the reasonably-distributed step length and roller bending force of a CVC roller are obtained, and through collected disturbance factors, the CVC roller bending force is obtained. And a corresponding roll bending force compensation value and a corresponding step length compensation value of the CVC roll are obtained, and finally dynamic control over the CVC roll and the bending roll is formed. According to the method, smooth transition of the channeling amount of the CVC roller is achieved through optimization treatment of step size amplitude limiting of the CVC roller, the systematic control capacity is improved by combining linkage of the bending roller and the CVC roller, the systematic disturbance rejection capacity is improved through depth cooperation of static setting and dynamic adjustment, and the stability of a roller gap and the strip shape quality of strip steel are guaranteed.

Description

Technical Field

[0001] The invention relates to the field of hot-rolled plate and strip steel rolling shape control, in particular to a CVC roll control method and system for hot-rolled plate and strip steel. Background Art

[0002] During the hot rolling process of strip steel, the control of CVC rolls (Continuous Variable Crown) and bending rolls is crucial to ensure the crown and straightness of the strip steel. Existing bending rolls and CVC rolls are usually controlled separately on the hot rolling production line, and the bending rolls and CVC rolls are not effectively coordinated. When rolling thin-gauge strip steel, the control of the plate shape is more sensitive. Because the material is thinner, it is more likely to have problems such as edge waves and middle waves. Traditional control methods often rely on fixed parameter settings, which are difficult to adapt to various disturbances that occur during the rolling process of thin-gauge strip steel, resulting in uneven product thickness and low yield rate. Summary of the invention

[0003] The purpose of the present invention is to provide a CVC roll control method and system for hot-rolled plate and strip steel in response to the problem that related technologies are difficult to adapt to the rolling of thin-gauge strip steel, which can effectively improve the adjustment ability of the roll gap and improve the plate shape, is particularly beneficial to the rolling of thin-gauge strip steel, and has good control stability.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is a CVC roll control method for hot rolled strip steel, comprising: S1. Divide the thickness and width of the strip into multiple gears to form a data table of CVC roll step length limit; S2. Obtain the target thickness Hx and target width Bx of the strip, and obtain the correction value Sx of the CVC roller step limit of the stand in combination with the data table; S3, obtaining the target roll gap crown C1, determining the initial step length S0 of the CVC roll and the actual crown contribution C2 of the CVC roll in combination with the correction value Sx, and obtaining the initial roll bending force L to be compensated based on C1 and C2; S4, based on the initial step length S0 of the CVC roll and the initial bending roll force L, the bending roll and the CVC roll are controlled to perform rolling, and multiple disturbance factors of the frame are collected in real time, each disturbance factor is respectively provided with a corresponding threshold value, and the bending roll force compensation value and / or the CVC roll step length compensation value required for each disturbance factor is calculated according to the threshold value; S5. Obtaining a dynamic adjustment amount ΔLc of the bending roll force according to the bending roll force compensation value, and / or obtaining a dynamic adjustment amount ΔS of the CVC roll step length according to the CVC roll step length compensation value; S6. Obtain the CVC roll step S0 + ΔS and the bending roll force L + ΔLc corresponding to each of the stands Fi (i = 1, 2, 3, 4, 5, 6, 7) according to steps S2 - S5, and perform dynamic control on the CVC rolls and bending rolls of the stand Fi.

[0005] In some alternative embodiments, in step S4, the multiple disturbance factors include the rolling force fluctuation ΔP, the strip transverse temperature gradient ΔT, and the strip deviation amount ΔD, and corresponding first, second, and third thresholds are set in sequence; When ΔP is greater than the first threshold, preferentially adjust the bending roll force to obtain the bending roll force compensation value ΔLp; when ΔT is greater than the second threshold, synchronously adjust the bending roll and the CVC roll to obtain the CVC roll step compensation value ΔSt and the bending roll force compensation value ΔLt; when ΔD is greater than the third threshold, preferentially adjust the CVC roll to obtain the CVC roll step compensation value ΔSd.

[0006] In some alternative embodiments, in step S5, obtaining the dynamic adjustment amount ΔLc of the bending roll force based on the bending roll force compensation value, and / or obtaining the dynamic adjustment amount ΔS of the CVC roll step based on the CVC roll step compensation value includes: Based on ΔLp, ΔSt, ΔLt, ΔSd, obtain the dynamic adjustment amount ΔS of the CVC roll step as ΔS = ΔSt + ΔSd, and satisfy |ΔS| ≤ 0.4Sx; the dynamic adjustment amount ΔLc of the bending roll force is ΔLc = ΔLp + ΔLt, and satisfy |ΔLc| ≤ 0.2L.

[0007] In some alternative embodiments, step S4 further includes: real - time collecting the roll wear amount ΔW of the stand, when ΔW is greater than the fourth threshold, updating the CVC roll step limit to Sx', and the updated bending roll force compensation value Sx' satisfies |ΔS| ≤ 0.4Sx'.

[0008] In some alternative embodiments, after obtaining the bending roll force compensation value ΔLp in step S4, it further includes updating the bending roll force compensation value ΔLp' by combining the dynamic damping coefficient ζ, ΔLp' = ζ * ΔLp, where ζ = 1 / (1 + τ·|ΔP|), τ is the stand response time constant; and using the updated bending roll force compensation value ΔLp' to obtain the dynamic adjustment amount ΔLc of the bending roll force.

[0009] In some alternative embodiments, set the rolling force fluctuation ΔP, the strip transverse temperature gradient ΔT, and the strip deviation amount ΔD as the disturbance compensation processing priorities from high to low in sequence, and determine ΔLp, ΔSt, ΔLt, ΔSd based on the limits of Sx and L in sequence.

[0010] In some alternative embodiments, the method of dividing the thickness and width of the strip into multiple grades respectively to form a data table of the CVC roll step limit includes: It is divided into multiple gears according to the thickness of the strip steel. Each gear is provided with a thickness reference point H, and each thickness reference point H corresponds to a preset basic value Si of the CVC roll step limit (i = 1, 2, 3, 4, 5, 6, 7). It is divided into multiple gear intervals according to the width of the strip steel. Each gear interval is provided with a width reference point B, and each gear interval corresponds to an influence coefficient b of the preset CVC roll step length.

[0011] In some alternative embodiments, the obtaining of the target thickness Hx and the target width Bx of the strip steel and the calculation of the correction value Sx of the CVC roll step limit of the stand by combining the data table includes: Select two thickness reference points H1 and H2 adjacent to the target thickness Hx and the width interval corresponding to the target width Bx according to the data table, determine the corresponding width reference point B and the influence coefficient b, and obtain the correction value Sx based on the following formula: Sx = S1i + (S2i - S1i)(Hx - H1) / (H2 - H1) + b(Bx - B), where S1i and S2i are the basic values of the CVC roll step length corresponding to the thickness reference points H1 and H2 of the stand Fi (i = 1, 2, 3, 4, 5, 6, 7).

[0012] In some alternative embodiments, 1.5 mm, 3 mm, and 6 mm are used as three thickness reference points H to divide the strip steel thickness into three gears.

[0013] In some alternative embodiments, the strip steel width is divided into three gear intervals according to less than 1000 mm, 1000 - 1500 mm, and greater than 1500 mm. The width reference points B of each gear interval are set to 1000 mm, 1000 mm, and 1500 mm in sequence, and the influence coefficients b corresponding to the three gear intervals are 12%, 15%, and 18% in sequence.

[0014] In some alternative embodiments, the target roll crown C1 is determined according to the usage requirements of downstream customers, control requirements, and / or equipment capabilities.

[0015] In some alternative embodiments, the determination of the initial step length S0 of the CVC roll and the actual crown contribution amount C2 of the CVC roll by combining the correction value Sx further includes that C2 / C1 is within the range of 60% - 80%.

[0016] A CVC roll control system for hot-rolled strip steel includes: A data module for dividing the thickness and width of the strip steel into multiple gears respectively to form a data table of the CVC roll step limit; A step length correction module for obtaining the target thickness Hx and the target width Bx of the strip steel and obtaining the correction value Sx of the CVC roll step limit of the stand by combining the data table; An initial value module is used to obtain the target roll crown C1, determine the initial step S0 of the CVC roll and the actual crown contribution C2 of the CVC roll in combination with the correction value Sx, and obtain the initial bending roll force L to be compensated based on C1 and C2; A compensation module controls the bending roll and the CVC roll for rolling based on the initial step S0 of the CVC roll and the initial bending roll force L, and collects multiple disturbance factors of the rolling mill in real time. Each disturbance factor is respectively provided with a corresponding threshold value, and calculates the bending roll force compensation value and / or the CVC roll step compensation value required for each disturbance factor according to the threshold value; A dynamic adjustment module is used to obtain the dynamic adjustment amount ΔLc of the bending roll force according to the bending roll force compensation value, and / or obtain the dynamic adjustment amount ΔS of the CVC roll step according to the CVC roll step compensation value; A control module is used to obtain the CVC roll step S0 + ΔS and the bending roll force L + ΔLc corresponding to the rolling mills Fi (i = 1, 2, 3, 4, 5, 6, 7) respectively according to steps S2 - S5, and perform dynamic control on the CVC roll and the bending roll of the rolling mill Fi.

[0017] A CVC roll control method and system for hot-rolled strip steel according to the present invention can perform detailed grading calculations according to the width and thickness of the strip steel through the optimization process of the CVC roll step limit. When producing strip steels of different specifications during the rolling process, it realizes the smooth transition of the CVC roll shift amount, combines the bending roll and the CVC roll to control the roll crown, improves the systematic control ability, and through the deep coordination of static setting and dynamic adjustment, can effectively cope with the disturbance effects during the rolling process, improves the systematic anti-disturbance ability, and ensures the stability of the roll gap and the shape quality of the strip steel. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts.

[0019] Figure 1 It is a schematic flow chart of a CVC roll control method for hot-rolled strip steel provided in this embodiment; Figure 2 It is a schematic diagram of a data table provided in this embodiment; Figure 3 It is a schematic structural diagram of a CVC roll control system for hot-rolled strip steel provided in this embodiment. Detailed Embodiments

[0020] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] Currently, the stroke of the CVC roll on the hot rolling line is ±140 mm. In the secondary model control table, there is only the roll shifting strategy for all steel grades, and there is no detailed grading and optimization according to the actual situation. When rolling thicker strip steel, a larger crown compensation is required because thick strip steel is more likely to have edge thinning or center bulging problems during rolling. For thinner strip steel, the requirements for flatness may be higher, and the adjustment of the roll shifting amount may need to be more precise to avoid unstable flatness caused by excessive roll shifting.

[0022] According to the current roll shifting step control method, the roll shifting amount is often too large when rolling thin gauges, resulting in unstable control of the roll gap and crown, causing overshoot in the control of the last stand and unable to ensure the thickness stability when rolling thin gauges. At the same time, different width strip steels have different sensitive areas for the roll gap shape, and the concentration points of the rolling force for wide and narrow strip steels are different. To ensure the stability of the roll gap, targeted control of the CVC roll is required.

[0023] The present invention will be described below in conjunction with the accompanying drawings and with reference to specific embodiments.

[0024] As Figure 1 shown, a CVC roll control method for hot rolled strip steel of the present invention includes: S1. Divide the thickness and width of the strip steel into multiple grades respectively to form a data table of the CVC roll step limit; S2. Obtain the target thickness Hx and target width Bx of the strip steel, and combine with the data table to obtain the correction value Sx of the CVC roll step limit of the stand; S3. Obtain the target roll gap crown C1, determine the initial step S0 of the CVC roll and the actual crown contribution amount C2 of the CVC roll in combination with the correction value Sx, and obtain the initial bending roll force L to be compensated based on C1 and C2; S4. Control the bending roll and the CVC roll for rolling based on the initial step S0 of the CVC roll and the initial bending roll force L, and collect multiple disturbance factors of the stand in real time. Each disturbance factor is respectively provided with a corresponding threshold value, and calculate the bending roll force compensation value and / or the CVC roll step compensation value required for each disturbance factor according to the threshold value; S5. Obtain the dynamic adjustment amount ΔLc of the bending roll force according to the bending roll force compensation value, and / or obtain the dynamic adjustment amount ΔS of the CVC roll step according to the CVC roll step compensation value; S6. Obtain the CVC roll step S0+ΔS and the bending roll force L+ΔLc corresponding to each of the stands Fi (i = 1, 2, 3, 4, 5, 6, 7) according to steps S2 - S5, and perform dynamic control on the CVC rolls and bending rolls of the stand Fi.

[0025] In some alternative embodiments, in step S4, the multiple disturbance factors include the rolling force fluctuation ΔP, the strip transverse temperature gradient ΔT, and the strip deviation ΔD, and corresponding first, second, and third thresholds are provided in sequence.

[0026] When ΔP is greater than the first threshold, preferentially adjust the bending roll force to obtain the bending roll force compensation value ΔLp.

[0027] Since the rolling force fluctuation ΔP directly reflects the instantaneous change in the deformation resistance of the rolled piece, and it is transmitted to the roll gap through the mill stiffness, which will cause rapid fluctuations in the roll gap convexity and rolling torque. By setting the adjustment priority of the bending roll and CVC roll, the rapid response characteristic of the bending roll can be used to stabilize the roll gap convexity, avoiding the imbalance of the second flow rate (such as thickness fluctuation or increased deviation) caused by lag. At the same time, the preferential adjustment of the bending roll force can avoid mechanical wear caused by frequent adjustment of the CVC roll. In addition, if the compensation of the bending roll force exceeds its own adjustment range, the step of the CVC roll can be controlled in coordination to make up for it.

[0028] When ΔT is greater than the second threshold, synchronously adjust the bending roll and CVC roll to obtain the CVC roll step compensation value ΔSt and the bending roll force compensation value ΔLt.

[0029] Since the strip transverse temperature gradient will cause thermal expansion differences, resulting in thermal convexity effect and thermal stress effect, through the synchronous control of the bending roll and CVC roll, the convexity-flatness coordinated control can be realized, that is, using the bending deformation of the bending roll to offset the internal bending moment of the strip caused by thermal stress, suppressing flatness defects, and at the same time using the CVC roll to change the superposition amount of the CVC roll profile curve, directly correcting the equivalent convexity deviation caused by the temperature gradient, reducing the quality risk of insufficient correction in single control.

[0030] When ΔD is greater than the third threshold, preferentially adjust the CVC roll to obtain the CVC roll step compensation value ΔSd.

[0031] Since the strip deviation ΔD is essentially caused by the transverse asymmetric force on the rolling line (such as uneven tension distribution, roll gap inclination), resulting in the transverse displacement of the strip. Preferentially using the CVC roll for adjustment can change the transverse equivalent convexity distribution of the roll gap (such as the convexity difference between the left / right roll gaps) by axially moving the work roll, generating a transverse torque to offset the deviation force. At the same time, by limiting the compensation amplitude, the stress concentration in the contact area at the end of the roll can be effectively avoided. Compared with the bending roll adjustment, the CVC roll can directly generate a transverse torque to correct the deviation, avoiding the deterioration of the roll system force.

[0032] In some alternative embodiments, in step S5, obtaining the dynamic adjustment amount ΔLc of the bending roll force according to the bending roll force compensation value, and / or obtaining the dynamic adjustment amount ΔS of the CVC roll step according to the CVC roll step compensation value includes: Obtaining the dynamic adjustment amount ΔS = ΔSt + ΔSd of the CVC roll step according to ΔLp, ΔSt, ΔLt, ΔSd, and satisfying |ΔS| ≤ 0.4Sx; the dynamic adjustment amount ΔLc of the bending roll force = ΔLp + ΔLt, and satisfying |ΔLc| ≤ 0.2L.

[0033] Determining the total dynamic adjustment amounts of the CVC roll and the bending roll according to different disturbance factors, and further setting a technical solution for preventing overshoot, that is, the adjustment amount ΔS of the CVC roll step within a single sensor acquisition cycle does not exceed 40% of the step limit Sx' dynamically updated by the CVC roll, which can balance mechanical safety, control stability and multi-disturbance response ability, avoid the vicious cycle of "overcorrection - oscillation", prevent the adjustment amount of the axial movement of the CVC roll from being too large, reduce the risk that the local stress peak value of the CVC roll exceeds the material fatigue limit and then cracks. It can be known through actual measurement that the phenomenon of cumulative overshoot can be significantly reduced, and sufficient adjustment margin can be reserved for subsequent compensation; at the same time, the dynamic adjustment amount ΔLc of the bending roll force within a single sensor acquisition cycle does not exceed 20% of the compensated bending roll force L, which can match the hydraulic dynamic characteristics and the second flow rate balance, realize the closed-loop control of "fast response - precise convergence", effectively ensure the oil film stability, and reduce the risk of pressure oscillation caused by the response lag of the spool.

[0034] In some alternative embodiments, step S4 further includes: real-time collecting the roll wear amount ΔW of the rolling mill stand. When ΔW is greater than the fourth threshold, updating the step limit of the CVC roll to Sx', and the updated bending roll force compensation value Sx' satisfies |ΔS| ≤ 0.4Sx'.

[0035] Coupling the roll wear amount ΔW to the calculation of the CVC roll step limit can realize the online adaptive compensation of the wear amount, avoid the model mismatch caused by the roll shape change, such as the systematic deviation between the convexity set value and the actual value, and extend the service life of the roll.

[0036] In some alternative embodiments, after obtaining the bending roll force compensation value ΔLp in step S4, it further includes updating the bending roll force compensation value ΔLp' in combination with the dynamic damping coefficient ζ, ΔLp' = ζ * ΔLp, where ζ = 1 / (1 + τ·|ΔP|), τ is the stand response time constant; and using the updated bending roll force compensation value ΔLp' to obtain the dynamic adjustment amount ΔLc of the bending roll force.

[0037] By introducing the dynamic damping coefficient ζ to calculate the bending roll force compensation value of the rolling force fluctuation, the system oscillation caused by the sudden change of the rolling force can be effectively suppressed, and together with the limiting of the bending roll force, it can form a double protection of "feedforward suppression + feedback truncation", that is, the dynamic damping coefficient is used to reduce the oscillation energy from the source, and the dynamic adjustment amount of the bending roll force is limited to prevent loss of control under extreme working conditions.

[0038] In some optional embodiments, the rolling force fluctuation ΔP, the strip transverse temperature gradient ΔT, and the strip deviation ΔD are set as disturbance compensation processing priorities from high to low, and ΔLp, ΔSt, ΔLt, and ΔSd are determined in sequence based on the limits of Sx and L.

[0039] Targeted design of more effective adjustment priorities based on different disturbance factors can effectively optimize the control effect, avoid calculation confusion in multiple disturbance overlapping scenarios, and improve the ability to handle unforeseen disturbance factors.

[0040] In some optional embodiments, the thickness and width of the strip are divided into a plurality of gears to form a data table of CVC roll step length limitation, including: According to the thickness of the strip, it is divided into multiple gears, each gear is provided with a thickness reference point H, each thickness reference point H corresponds to a preset CVC roller step limit basic value Si (i=1, 2, 3, 4, 5, 6, 7); according to the width of the strip, it is divided into multiple gear intervals, each gear interval is provided with a width reference point B, and each gear interval corresponds to a preset CVC roller step influence coefficient b.

[0041] It can be divided into detailed grades according to the width and thickness of the strip, so as to obtain smoother initial values ​​for subsequent calculations.

[0042] In some optional embodiments, the target thickness Hx and target width Bx of the strip are obtained, and the correction value Sx of the CVC roll step limit of the rack is calculated in combination with the data table, including: According to the data table, select two thickness reference points H1 and H2 adjacent to the target thickness Hx, and the width interval corresponding to the target width Bx, determine the corresponding width reference point B and influence coefficient b, and obtain the correction value Sx based on the following formula: Sx=S1i+(S2i-S1i)(Hx-H1) / (H2-H1)+b(Bx-B), where S1i and S2i are the basic values ​​of the CVC roller step lengths corresponding to the thickness reference points H1 and H2 of the frame Fi (i=1, 2, 3, 4, 5, 6, 7).

[0043] This formula can achieve a smooth transition of the CVC roll step length when producing strips of different specifications during the rolling process.

[0044] In some alternative embodiments, 1.5 mm, 3 mm, and 6 mm are used as three thickness reference points H to divide the strip thickness into three grades.

[0045] Since thin-gauge strips are sensitive to roll gap fluctuations, the fixed step size of traditional CVC rolls can lead to lag or excessive adjustment of the roll gap. Therefore, by specifically dividing the strips with a thickness of 1.5 mm - 6 mm into grades, thin-gauge strips can be effectively refined to obtain more accurate control parameters, thereby improving the control stability and forming quality of rolling thin-gauge strips.

[0046] In some alternative embodiments, the strip width is divided into three grade intervals according to less than 1000 mm, 1000 - 1500 mm, and greater than 1500 mm. The width reference points B for each grade interval are set to 1000 mm, 1000 mm, and 1500 mm in sequence, and the corresponding influence coefficients b for the three grade intervals are 12%, 15%, and 18% respectively.

[0047] Since wide-width strips have higher requirements for the uniformity of roll gap crown, a larger shifting amount is usually required to compensate for the roll system deflection caused by rolling force. However, for narrow-width strips, excessive shifting amount will cause too high local crown of the roll gap, leading to "cat ear" defects. Therefore, dividing the width into three grade intervals can use the preset influence coefficients to calculate the step size limit of the CVC roll. On the basis of ensuring smooth transition of the shifting amount, it can effectively improve the stability of rolling wide-width strips. The setting of the influence coefficients enables the step size limit of the CVC roll to be accurately adjusted according to the strip width. Especially during the rolling process, after the strip width changes, it can synchronously respond to obtain the optimal control parameters. In addition, when establishing the corresponding base value Si according to the strip thickness grade, the strip width of 1000 mm can be selected as the default specification to facilitate obtaining the optimal base value Si based on experience.

[0048] In some alternative embodiments, the target roll gap crown C1 is determined according to the usage requirements of downstream customers, control requirements, and / or equipment capabilities.

[0049] In some alternative embodiments, the initial step size S0 of the CVC roll and the actual crown contribution amount C2 of the CVC roll are determined in combination with the correction value Sx, and C2 / C1 is also within the range of 60% - 80%.

[0050] The step size of the CVC roll can cover 60% - 80% of the crown requirements. By combining the bending roll force to compensate for the remaining 20% - 40% of the crown requirements, it can reasonably allocate the weight ratio of the bending roll and the CVC roll, which is beneficial for subsequent dynamic adjustment to have sufficient compensation margin.

[0051] Based on the requirements of specific working conditions, certain selections and combinations are made among various optional implementation methods. A CVC roll control method for hot-rolled strip steel specifically includes the following steps: S1. Divide the thickness and width of the strip steel into multiple grades respectively to form a data table of CVC roll step limit.

[0052] Specifically, according to the strip steel thickness, the CVC roll step limit of stands F1 - F7 is divided into three grades. The strip steel thicknesses corresponding to the thickness reference points H of the three grades are 1.5 mm, 3 mm, and 6 mm respectively. At the same time, according to the strip steel width, the CVC roll step limit of stands F1 - F7 is divided into three grade intervals. The strip steel widths corresponding to the three grade intervals are less than 1000 mm, 1000 - 1500 mm, and more than 1500 mm respectively, and the corresponding width reference points B are 1000 mm, 1000 mm, and 1500 mm respectively.

[0053] It should be noted that the width reference points B for less than 1000 mm and 1000 - 1500 mm are both 1000 mm. This is because when determining the basic value Si according to experience, the width of 1000 mm is used as the default specification. That is, when the width of the rolled strip steel is greater than 1000 mm, a larger shifting amount is required to compensate for the roll system deflection caused by the rolling force. Accordingly, a certain CVC roll step limit is increased on the basis of the basic value Si to meet the process requirements. While when the width of the rolled strip steel is less than 1000 mm, the CVC roll step limit can be reduced on the basis of the basic value Si to fully improve the rolling stability.

[0054] Specifically, a data table of the basic value of the CVC roll step limit of the stand as shown in Figure 2 can be established according to the strip steel thickness. And for the grade interval with the strip steel width less than 1000 mm, the preset CVC roll step influence coefficient b = 12%, which is applicable to all seven stands F1 - F7; for the grade interval with the strip steel width of 1000 - 1500 mm, the preset CVC roll step influence coefficient b = 15%, which is applicable to all seven stands F1 - F7; for the grade interval with the strip steel width greater than 1500 mm, the preset CVC roll step influence coefficient b = 18%, which is applicable to all seven stands F1 - F7.

[0055] S2. Obtain the target thickness Hx and target width Bx of the strip steel, and combine with the data table to obtain the correction value Sx of the CVC roll step limit of the stand.

[0056] Specifically, it includes performing the following operations on each stand: selecting two thickness reference points H1 and H2 adjacent to the target thickness Hx and the width interval corresponding to the target width Bx in the data table, determining the corresponding width reference point B and the influence coefficient b, and then obtaining the correction value Sx based on the following formula: Sx = S1i + (S2i - S1i)(Hx - H1) / (H2 - H1) + b(Bx - B), where S1i and S2i are the basic values of the CVC roll step length corresponding to the thickness reference points H1 and H2 of stand Fi (i = 1, 2, 3, 4, 5, 6, 7).

[0057] For example, when the target thickness of the strip is 2 mm and the target width is 1200 mm, for stand F1, two adjacent thickness reference points H1 = 1.5 mm and H2 = 3 mm are selected in the data table. According to Figure 1 it can be known that the preset basic value of the CVC roll step length limit S11 = 35 μm at the reference point H1 = 1.5 mm of stand F1, and the preset basic value of the CVC roll step length limit S21 = 80 μm at the reference point H2 = 3 mm of stand F1. The target thickness of the strip belongs to the width interval of 1000 - 1500 m, so the corresponding influence coefficient b of the CVC roll step length is 15%, and the reference point B = 1000 mm. Therefore, according to the formula, the correction value Sx of the CVC roll step length limit of stand F1 can be obtained: Sx = 35 + (80 - 35)*(2 - 1.5) / (3 - 1.5) + 15%*(1200 - 1000) = 80 μm. Similarly, it can be known that the preset basic value of the CVC roll step length limit S12 = 30 μm at the reference point H1 = 1.5 mm of stand F2, and the preset basic value of the CVC roll step length limit S22 = 60 μm at the reference point H2 = 3 mm of stand F2, and the corresponding influence coefficient b of the CVC roll step length is also 15%. Therefore, according to the formula, the correction value Sx of the CVC roll step length limit of stand F2 can be obtained: Sx = 30 + (60 - 30)*(2 - 1.5) / (3 - 1.5) + 15%*(1200 - 1000) = 70 μm. The calculation principles for stands F3 - F7 are the same and will not be elaborated here.

[0058] Another example is when the target thickness of the strip is 3 mm and the target width is 900 mm. The target thickness exactly corresponds to one of the thickness reference points, and the reference point B of the target width is 1000 mm. Similarly, the correction value Sx of the CVC roll step length limit of stand F1 can be obtained: Sx = 80 + 12%*(900 - 1000) = 68 μm. The calculation principles for stands F2 - F7 are the same and will not be elaborated here.

[0059] S3. Obtain the target roll crown C1, determine the initial step length S0 of the CVC roll and the actual crown contribution C2 of the CVC roll in combination with the correction value Sx, and obtain the initial bending roll force L to be compensated based on C1 and C2.

[0060] Specifically, the target roll gap crown can be calculated through the target cross-section of the strip steel (such as parabolic crown and edge thinning), combined with the rolling force prediction model. The CVC roll step size S0 of each stand is determined according to the actual working conditions under the constraint of the corresponding Sx. The actual crown contribution C2 of the CVC roll can be determined by S0 through the CVC characteristic curve (axial displacement - crown mapping). Finally, based on the formula L = k*(C2 - C1), where k is the elastic deformation coefficient of the corresponding stand. In addition, L, C1, and C2 can also be calculated using other existing technologies, which are not restricted here.

[0061] S4. During rolling, control the bending rolls and the CVC rolls based on the initial step size S0 of the CVC roll and the initial bending roll force L, and collect multiple disturbance factors of the stand in real time. Each disturbance factor is respectively provided with a corresponding threshold value, and calculate the bending roll force compensation value and / or the CVC roll step size compensation value required for each disturbance factor according to the threshold value.

[0062] That is, during rolling, each stand has an initial step size S0 of the CVC roll and an initial bending roll force L corresponding to it, and the previous static setting stage is completed accordingly, and then it enters the dynamic adjustment stage.

[0063] Specifically, during the rolling process, the disturbance factors of each stand are collected in real time through a sensor group, including the rolling force fluctuation ΔP, the strip steel transverse temperature gradient ΔT, the strip steel deviation ΔD, and the roll wear ΔW. Among them, the rolling force fluctuation ΔP can be detected and obtained through the combination of a piezoelectric pressure gauge and a strain type pressure sensor; the strip steel transverse temperature gradient ΔT can be detected and obtained through the combination of an infrared thermal imager and a multi-channel line scanning temperature measuring instrument, the strip steel deviation ΔD can be detected and obtained through the combination of a laser displacement sensor and a CCD vision sensor, and the roll wear ΔW can be detected and obtained through the combination of a laser profiler and a vibration acceleration sensor.

[0064] When the rolling force fluctuation ΔP is greater than the first threshold value, the bending roll force is preferentially adjusted to obtain the bending roll force compensation value ΔLp for compensation. Specifically, according to the bending roll force compensation value ΔLp = c·ΔP, where c is the rolling force - bending roll force coupling coefficient.

[0065] In addition, the bending roll force compensation value can be further updated in combination with the dynamic damping coefficient ζ to obtain the updated bending roll force compensation value ΔLp'. Specifically, according to ΔLp' = ζ*ΔLp, where ζ = 1 / (1 + τ·|ΔP|), and τ is the stand response time constant.

[0066] When the cross - strip temperature gradient ΔT of the strip steel is greater than the second threshold, the bending rolls and CVC rolls are adjusted synchronously to obtain the CVC roll step compensation value ΔSt and the bending roll force compensation value ΔLt for compensation; specifically, according to the CVC roll step compensation value ΔSt = d·ΔT and the bending roll force compensation value ΔLt = e·ΔT, where d is the temperature - CVC roll correlation factor and e is the temperature - bending roll correlation factor.

[0067] When the strip steel deviation amount ΔD is greater than the third threshold, the CVC roll step is preferentially adjusted to obtain the CVC roll step compensation value ΔSd for compensation; specifically, according to the CVC roll step compensation value ΔSd = f·ΔD, where f is the deviation correction coefficient, and ΔSd ≤ 0.3Sx can be further restricted.

[0068] When the roll wear amount ΔW is greater than the fourth threshold, the CVC roll step limit is updated to obtain the CVC roll step limit Sx'; specifically, according to Sx' = Sx·(1 - ΔW / Wmax), where Wmax is the maximum allowable roll wear amount.

[0069] Meanwhile, the rolling force fluctuation amount ΔP, the cross - strip temperature gradient ΔT, and the strip steel deviation amount ΔD are set to have disturbance compensation processing priorities from high to low in sequence, and based on the limits of Sx' and L, ΔLp, ΔSt, ΔLt, and ΔSd are determined in sequence. In this way, by designing a more matching adjustment object and a more effective adjustment priority for different disturbance factors, the optimization control effect can be improved, and the processing ability for unforeseen disturbance factors can be enhanced.

[0070] S5. Obtain the dynamic adjustment amount ΔLc of the bending roll force according to the bending roll force compensation value, and / or obtain the dynamic adjustment amount ΔS of the CVC roll step according to the CVC roll step compensation value.

[0071] Specifically, according to ΔLp', ΔSt, ΔLt, ΔSd, and ΔW, the dynamic adjustment amount ΔS of the CVC roll step is obtained as ΔS = ΔSt + ΔSd, and |ΔS| ≤ 0.4Sx' is satisfied; the dynamic adjustment amount ΔLc of the bending roll force is obtained as ΔLc = ΔLp' + ΔLt, and |ΔLc| ≤ 0.2L is satisfied.

[0072] S6. Obtain the CVC roll step S0 + ΔS and the bending roll force L + ΔLc corresponding to each of the stands Fi (i = 1, 2, 3, 4, 5, 6, 7) according to steps S2 - S5, and perform dynamic control on the CVC rolls and bending rolls of the stand Fi.

[0073] Specifically, all seven frames will go through the static setting stage and the dynamic adjustment stage. After calculating the initial step length and initial bending roll force of each frame respectively, they will enter the rolling stage. Then the sensors can collect the disturbance factors of each frame respectively, and then determine the CVC roll step length and bending roll force of each frame dynamically adjusted in turn. Of course, based on the data processing capability, it is also possible to evaluate the risk of disturbance severity caused by different disturbance factors for frames in different positions, and then selectively collect different disturbance factors for different frames, thereby realizing personalized dynamic control of each frame.

[0074] The present invention provides a CVC roller control method for hot-rolled plate and strip steel. By optimizing the step limit of the CVC roller, the method can perform detailed grading calculation according to the width and thickness of the strip steel. When rolling and producing strip steels of different specifications, the method can realize a smooth transition of the CVC roller's channeling amount, effectively avoiding abnormal roll gap convexity when the specifications of the strip steel on the rolling line are changed. The method further combines the bending roll force to perform convexity compensation, and makes full use of the control weights of the CVC roller and the bending roll to achieve the required roll gap convexity requirements. On the basis of ensuring the plate shape quality of the strip steel, the stability of the roll gap is effectively guaranteed.

[0075] At the same time, during the rolling process, a dynamic adjustment strategy was designed based on the disturbance factors obtained by the sensor, that is, on the basis of static settings, real-time optimization control can be performed according to the working conditions, including: through the disturbance classification compensation mechanism, differentiated compensation strategies are designed for the four types of disturbances, namely rolling force, strip lateral temperature, strip deviation, and roll wear, breaking through the limitations of a single compensation model; dynamic priority logic is adopted to give priority to the bending roll response speed when the rolling force changes suddenly, and the CVC roll and the bending roll are adjusted synchronously when the temperature is abnormal to achieve optimal configuration of control resources; a multi-constraint anti-overshoot algorithm is introduced to ensure system stability through the triple protection of the amplitude limit of the single adjustment of the CVC roll step size, the amplitude limit of the single-cycle adjustment of the bending roll force, and the dynamic damping coefficient.

[0076] This application achieves significant improvement in the anti-disturbance capability of the system while ensuring the accuracy of convexity control through deep coordination of static setting and dynamic adjustment. In particular, when rolling wide and thin strip steel, it can avoid excessive adjustment of the convexity that causes the strip edge to be too thin, or overshoot of the downstream frame and steel piling due to plate shape fluctuations. This improves the control performance of thin strip rolling in an all-round way. After actual measurement of rolling thin strip steel with a thickness of 2mm and a width of 1600mm on the company's production line, the thickness stability of the strip steel has been effectively improved, the thickness tolerance has been reduced from ±15μm to ±7μm, the plate shape has been improved, the occurrence rate of edge waves and middle waves has been reduced by about 30%, and the yield rate has been increased by 5%. It has good application prospects.

[0077] The following describes a CVC roll control system for hot-rolled strip steel provided by the present application. The system described below can be correspondingly referred to the method described above. Based on the above embodiments, Figure 3 is a schematic structural diagram of a CVC roll control system for hot-rolled strip steel provided by the present application. As shown in Figure 3 , the system includes: a data module 10 for dividing the thickness and width of the strip into multiple grades respectively to form a data table for CVC roll step limit; a step correction module 20 for obtaining the target thickness Hx and target width Bx of the strip, and obtaining the correction value Sx of the CVC roll step limit of the stand in combination with the data table; an initial value module 30 for obtaining the target roll gap crown C1, determining the initial step S0 of the CVC roll and the actual crown contribution amount C2 of the CVC roll in combination with the correction value Sx, and obtaining the initial bending roll force L to be compensated based on C1 and C2; a compensation module 40 for controlling the bending roll and the CVC roll to perform rolling based on the initial step S0 of the CVC roll and the initial bending roll force L, and collecting multiple disturbance factors of the stand in real time. Each disturbance factor is respectively provided with a corresponding threshold value, and calculating the bending roll force compensation value and / or CVC roll step compensation value required for each disturbance factor according to the threshold value; a dynamic adjustment module 50 for obtaining the dynamic adjustment amount ΔLc of the bending roll force according to the bending roll force compensation value, and / or obtaining the dynamic adjustment amount ΔS of the CVC roll step according to the CVC roll step compensation value; a control module 60 for obtaining the CVC roll step S0 + ΔS and the bending roll force L + ΔLc corresponding to the stands Fi (i = 1, 2, 3, 4, 5, 6, 7) respectively according to steps S2 - S5, and dynamically controlling the CVC roll and the bending roll of the stand Fi.

[0078] The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement without creative labor.

[0079] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the above technical solution, in essence, or the part that contributes to the prior art can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., including several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them; although the present disclosure has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present disclosure.

Claims

1. A CVC roll control method for hot-rolled strip steel, characterized in that: include: S1. Divide the thickness and width of the strip into multiple gears to form a data table of CVC roll step length limitation; S2. Obtain the target thickness Hx and target width Bx of the strip, and obtain the correction value Sx of the CVC roller step limit of the stand in combination with the data table; S3, obtaining the target roll gap crown C1, determining the CVC roll initial step length S0 and the CVC roll actual crown contribution C2 in combination with the correction value Sx, and obtaining the initial roll bending force L to be compensated based on C1 and C2; S4, based on the initial step length S0 of the CVC roll and the initial bending roll force L, the bending roll and the CVC roll are controlled to perform rolling, and multiple disturbance factors of the frame are collected in real time, each disturbance factor is respectively provided with a corresponding threshold value, and the bending roll force compensation value and / or the CVC roll step length compensation value required for each disturbance factor is calculated according to the threshold value; S5. Obtaining a dynamic adjustment amount ΔLc of the bending roll force according to the bending roll force compensation value, and / or obtaining a dynamic adjustment amount ΔS of the CVC roll step length according to the CVC roll step length compensation value; S6. According to steps S2-S5, the CVC roller step length S0+ΔS and the bending roller force L+ΔLc corresponding to the rack Fi (i=1, 2, 3, 4, 5, 6, 7) are obtained, and the CVC roller and bending roller of the rack Fi are dynamically controlled.

2. The CVC roll control method for hot-rolled strip steel according to claim 1, characterized in that: In step S4, the plurality of disturbance factors include rolling force fluctuation ΔP, strip transverse temperature gradient ΔT and strip deviation ΔD, and corresponding first threshold, second threshold and third threshold are sequentially set; When ΔP is greater than the first threshold, the bending roll force is adjusted first to obtain the bending roll force compensation value ΔLp; when ΔT is greater than the second threshold, the bending roll and CVC roll are adjusted synchronously to obtain the CVC roll step length compensation value ΔSt and the bending roll force compensation value ΔLt; when ΔD is greater than the third threshold, the CVC roll is adjusted first to obtain the CVC roll step length compensation value ΔSd.

3. The CVC roll control method for hot-rolled strip steel according to claim 2, characterized in that: In step S5, the dynamic adjustment amount ΔLc of the bending roll force is obtained according to the bending roll force compensation value, and / or the dynamic adjustment amount ΔS of the CVC roll step length is obtained according to the CVC roll step length compensation value, including: According to ΔLp, ΔSt, ΔLt, and ΔSd, the dynamic adjustment amount of the CVC roller step length ΔS=ΔSt+ΔSd is obtained, and |ΔS|≤0.4Sx is satisfied; the dynamic adjustment amount of the bending roller force ΔLc=ΔLp+ΔLt is obtained, and |ΔLc|≤0.2L is satisfied.

4. The CVC roll control method for hot-rolled strip steel according to claim 3, characterized in that: Step S4 also includes: collecting the roll wear amount ΔW of the stand in real time, and when ΔW is greater than a fourth threshold, updating the CVC roll step limit to Sx', and the updated bending roll force compensation value Sx' satisfies |ΔS|≤0.4Sx'.

5. The CVC roll control method for hot-rolled strip steel according to claim 3, characterized in that: After obtaining the bending roll force compensation value ΔLp in step S4, it also includes updating the bending roll force compensation value ΔLp' in combination with the dynamic damping coefficient ζ, ΔLp'=ζ*ΔLp, wherein ζ=1 / (1+τ·|ΔP|), τ is the frame response time constant; and using the updated bending roll force compensation value ΔLp' to obtain the dynamic adjustment amount ΔLc of the bending roll force.

6. The CVC roll control method for hot-rolled strip steel according to claim 3, characterized in that: The rolling force fluctuation ΔP, the strip transverse temperature gradient ΔT, and the strip deviation ΔD are set as disturbance compensation processing priorities from high to low, and ΔLp, ΔSt, ΔLt, and ΔSd are determined in sequence based on the limits of Sx and L.

7. The CVC roll control method for hot-rolled strip steel according to any one of claims 1 to 6, characterized in that: The data table for dividing the thickness and width of the strip into a plurality of gears to form the CVC roll step length limit comprises: According to the thickness of the strip, it is divided into multiple gears, each gear is provided with a thickness reference point H, each thickness reference point H corresponds to a preset CVC roller step limit basic value Si (i=1, 2, 3, 4, 5, 6, 7); according to the width of the strip, it is divided into multiple gear intervals, each gear interval is provided with a width reference point B, and each gear interval corresponds to a preset CVC roller step influence coefficient b.

8. The CVC roll control method for hot-rolled strip steel according to claim 7, characterized in that: The method of obtaining the target thickness Hx and target width Bx of the strip and calculating the correction value Sx of the CVC roll step limit of the rack in combination with the data table includes: According to the data table, select two thickness reference points H1 and H2 adjacent to the target thickness Hx, and the width interval corresponding to the target width Bx, determine the corresponding width reference point B and influence coefficient b, and obtain the correction value Sx based on the following formula: Sx=S1i+(S2i-S1i)(Hx-H1) / (H2-H1)+b(Bx-B), where S1i and S2i are the basic values ​​of the CVC roller step lengths corresponding to the thickness reference points H1 and H2 of the frame Fi (i=1, 2, 3, 4, 5, 6, 7).

9. The CVC roll control method for hot-rolled strip steel according to claim 7, characterized in that: The strip width is divided into three ranges according to less than 1000mm, 1000-1500mm and greater than 1500mm. The width reference point B of each range is set to 1000mm, 1000mm, 1500mm respectively, and the influence coefficients b corresponding to the three ranges are 12%, 15% and 18% respectively.

10. A CVC roller control system for hot-rolled strip steel, characterized in that: include: A data module, used to divide the thickness and width of the strip into multiple gears to form a data table of CVC roll step length limit; The step length correction module is used to obtain the target thickness Hx and target width Bx of the strip, and obtain the correction value Sx of the CVC roller step length limit of the stand in combination with the data table; The initial value module is used to obtain the target roll gap crown C1, determine the initial step length S0 of the CVC roll and the actual crown contribution C2 of the CVC roll in combination with the correction value Sx, and obtain the initial bending roll force L to be compensated based on C1 and C2; The compensation module controls the bending roll and the CVC roll for rolling based on the initial step length S0 of the CVC roll and the initial bending roll force L, and collects multiple disturbance factors of the stand in real time. Each disturbance factor is respectively provided with a corresponding threshold value, and the bending roll force compensation value and / or the CVC roll step length compensation value required for each disturbance factor is calculated according to the threshold value; A dynamic adjustment module, used for obtaining a dynamic adjustment amount ΔLc of the bending roll force according to the bending roll force compensation value, and / or obtaining a dynamic adjustment amount ΔS of the CVC roll step length according to the CVC roll step length compensation value; The control module is used to obtain the CVC roller step length S0+ΔS and the bending roller force L+ΔLc corresponding to the rack Fi (i=1, 2, 3, 4, 5, 6, 7) according to steps S2-S5, and dynamically control the CVC roller and bending roller of the rack Fi.

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