A method for evaluating flatness control capability

Abstract

The present invention relates to a method for evaluating the plate shape control capability, and belongs to the technical field of hot rolling methods. The technical solution of the present invention is: considering the plate shape control process of the bending rolls of the specific frame of the four-roll CVC hot rolling mill on the strip, by controlling the bending roll force of the specific frame of the hot rolling mill, the plate shape of the strip when it is at its narrowest, widest and average width, and when the rolling pressure is at its maximum, minimum and average value, and the plate shape adjustment range under this working condition is calculated. The beneficial effect of the present invention is: realizing the evaluation of the plate shape control capability of the hydraulic bending roll control technology of the specific frame of the four-roll CVC hot rolling mill, improving the plate shape control capability of the CVC hot rolling mill strip under the specific frame, and bringing better economic benefits to on-site strip production.

Description

Technical Field

[0001] The invention relates to a method for evaluating plate shape control capability, and belongs to the technical field of hot rolling methods. Background Art

[0002] In recent years, with the rapid development of my country's home appliance and automotive industries, customer demand for high-quality, technically demanding hot-rolled strip products has continued to increase. Requirements for strip product performance, variety, and cost control have also become increasingly stringent, leading to increasingly fierce competition in the hot-rolled strip market. Shape control accuracy is a critical quality indicator in the hot-rolled strip rolling process. Improving hot-rolled strip shape accuracy plays a crucial role in enhancing the market competitiveness of hot-rolled strip products. Hydraulic roll bending control technology is a key control method for strip shape control in four-high CVC hot-rolling mills and plays a crucial role in this process. By controlling the elastic deformation of the rolls during the rolling process through hydraulic control, the strip shape can be controlled within a specific range. Hydraulic roll bending technology uses hydraulic pressure to generate a certain amount of additional deflection in the work rolls or backup rolls to compensate for variations in the no-load roll gap caused by process factors such as rolling pressure and hot roll shape, ultimately ensuring that the hot-rolling mill produces high-precision strip products. Hydraulic roll bending technology is common in four-high CVC hot rolling mills. Based on the direction of the applied force, hydraulic roll bending can be categorized as positive or negative. Positive roll bending increases the roll crown, while negative roll bending decreases it. Based on the location of the bending force, hydraulic roll bending can be divided into single-bearing pedestal bending systems, multi-bearing pedestal bending systems, and pedestal-less systems. There are many different types of hydraulic roll bending mechanisms, the most significant difference being the location of the hydraulic cylinders. In earlier models, the cylinders were installed within the roll bearings, including those for the work and backup rolls. Modern mills typically use hydraulic cylinders mounted on raised blocks on the mill housing, transmitting force to the rolls through the cylinders to achieve positive or negative bending. This design overcomes the drawback of installing the cylinders within the bearings of the work or backup rolls, which requires the removal of the oil tubing. Traditionally, the hydraulic roll bending control process involves controlling the bending force applied to both ends of the work rolls through the hydraulic roll bending device of a four-high CVC hot rolling mill, thereby achieving strip shape control. Evaluating the shape control capability of hydraulic roll bending control in a four-high CVC hot rolling mill is of great practical significance for evaluating roll bending control accuracy and the shape control range. Currently, according to literature searches, most research on roll bending force control at home and abroad focuses on setting different bending force patterns, such as setting the bending force to a set of cyclically varying values and adjusting the parameters based on actual conditions to control strip shape. Alternatively, improvements to the roll bending device can be made to control the stability of the bending force. Alternatively, by considering the full-length strip shape process and combining the equipment's ultimate capacity, the necessary roll force adjustment is reserved for mid- and tail-end strip shape control, achieving shape control over the entire rolling process. However, there is limited research on evaluating the shape control capability of roll shifting within the limits of specific hot rolling mill equipment. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for evaluating the plate shape control capability, taking into account the plate shape control process of the bending rolls of the specific frame of the four-roll CVC hot rolling mill group on the strip, by controlling the bending roll force of the specific frame of the hot rolling mill group, calculating the plate shape of the strip when it is at the narrowest, widest and average width, and when the rolling pressure is at the maximum, minimum and average value, and finding the plate shape adjustment domain under the working condition, thereby realizing the evaluation of the plate shape control capability of the hydraulic bending roll control technology of the specific frame of the four-roll CVC hot rolling mill group, improving the plate shape control capability of the CVC hot rolling mill group strip under the specific frame, bringing better economic benefits to on-site strip production, and effectively solving the above-mentioned problems existing in the background technology.

[0004] The technical solution of the present invention is: a method for evaluating the plate shape control ability, comprising the following steps: (A) collecting equipment and process parameters of a four-roll CVC hot rolling mill; (B) collecting strip steel related parameters; (C) dividing the roll length and the plate strip length; (D) calculating some parameter values required for subsequent plate shape calculation; (E) calculating the bending roll force S as the minimum bending roll force S min The corresponding support force P in this case; (F) Calculate the influence function a of the deflection of the working roll and support roll in the i-th section caused by the load in the j-th section ij 、b ij , the influence coefficient of left and right bending roller force and support force on the deflection of segment i (G) Calculate the deformation coordination equation; (H) Calculate the outlet thickness h i and working roll deflection f wi ; (I) Calculate the bending roll force S as the maximum bending roll force S min (J) Judgement: Is it established? If not, let Go to step (D); if established, go to step (K); (K) calculate the maximum plate shape adjustment value; (L) similarly calculate the maximum plate shape adjustment value in the other six cases; (M) output the plate shape adjustment range under the specific frame of the four-roll CVC hot rolling mill.

[0005] In the step (A), the equipment and process parameters of the four-high CVC hot rolling mill include the working roll diameter D of the specific stand. w , support roller diameter D b , support roller body length L b , average value of post-tension and pre-tension The influence coefficient k of the front and rear tensile stress on the rolling force r , total rolling pressure q roll , the minimum, maximum and average total rolling pressure q' under a specific stand min ,q' max ,q' avr , minimum bending roll force S min , maximum bending roll force Smax , bending roll force arm and support force arm

[0006] In the step (B), the strip parameters include the actual strip width b, the strip elastic modulus and Poisson's ratio E, ν, the average strip inlet thickness H, the average strip outlet thickness h, the strip deformation resistance σ, and the narrowest, widest and average strip width b under a specific frame. n 、b w 、b avr .

[0007] In the step (C), the length of the support roll is divided into n2 parts, and the generalized rolling pressure is also divided into n2 parts, wherein the non-zero part of the rolling pressure contains n1 parts. For the convenience of calculation, n2 is written as 2n+1, and n1 is written as 2m+1, and i,j∈{1,2,...,2n+1}, the plate shape calculation iterative error ε, the work roll deflection influence function a of the specific stand ij , support roller deflection influence function b ij , left and right bending roll force deflection influence function Left and right support force deflection influence function The pressure value q between the rollers in the jth section j , rolling pressure value q' in the jth section j , the rigid rotation angle β of the working roll relative to the backup roll, ΔL tl is the maximum plate shape adjustment value between the minimum and maximum bending roll forces in the lth case (l=1,2,...,7), ΔL t It is the maximum plate shape adjustment value under the specific stand of the four-high CVC hot rolling mill.

[0008] In the step (D), the strip is considered to have a width of b=b n , the total rolling pressure is q roll =q' min , calculate some parameter values required for the subsequent plate shape calculation:

[0009] Where: x and x' are the lengths of the support roller body at the i-th and j-th positions respectively, Δx is the length of each roller body segment, x1 is the position of each segment divided by the incoming material shape, H i is the entrance thickness value of the i-th position of the divided incoming material plate shape, I w , I b are the moments of inertia of the working roll and the support roll, k1 and k2 are the coefficients of the influence functions of the working roll and the support roll, P(S) is the support force calculation function, q roll is the total rolling force for a particular stand.

[0010] In the step (E), the bending roll force S is calculated as the minimum bending roll force S min The corresponding support force in this case: P(S min )=(q roll +2×S min ) / 2.

[0011] In the step (F), the influence function a of the deflection of the working roll and the backup roll of the i-th section caused by the load of the j-th section is calculated. ij 、b ij , the influence coefficient of left and right bending roller force and support force on the deflection of segment i

[0012] Where: f1( c ,k i ,x j ), x is the influence function of the load on the deflection of the roller in the i-th section, where k c is the coefficient parameter of the influence function, x i 、x j are the position parameters of the loads in the i-th and j-th sections, respectively, and D c is the roller diameter parameter.

[0013] In the step (G), the sum of the roller diameter differences ΔD between the upper and lower working rolls is given i According to the metal plastic deformation model and the roll elastic deformation model, the deformation coordination equation of the work roll and the backup roll of the specific stand of the four-high CVC hot rolling mill is listed and solved:

[0014] Where: K is the flexibility coefficient of the working roll and the backup roll flattening each other, S1 and S2 are the bending roll forces at the left and right ends of the working roll respectively, C1 and C2 are the coefficient vectors on the right side of the equation group, and q roll is the total rolling pressure for a particular stand.

[0015] In the step (H), the specific stand bending roll force of the CVC hot rolling mill is calculated as the minimum bending roll force S min , and the strip width is b n , rolling pressure is q' min The outlet thickness h i , working roll deflection f wi :

[0016] Where: K' is the flattening coefficient between the work roll and the rolled piece, is the deflection of the upper working roll, Δh i The thickness difference between the entrance and exit.

[0017] In the step (I), the specific stand bending roll force S of the CVC hot rolling mill is calculated as the minimum bending roll force S min , and the strip width is b n , rolling pressure is q' min Similarly, according to the previous steps, the bending roll force S can be calculated as the maximum bending roll force S max Plate shape at:

[0018] Where: The strip width is b n , rolling pressure is q' min When the minimum bending roll force S min and maximum bending roll force S max The following flatness value.

[0019] In the step (J), ε is the calculated error of the plate shape of a specific stand of the CVC hot rolling mill, and it is determined that: Is i=n-m+1,...,n+m+1? If not, let i=n-m+1,...,n+m+1, go to step (D); if established, go to step (K).

[0020] In the step (K), the minimum bending roll force S is calculated respectively. min and maximum bending roll force S max The plate shape value and calculate the maximum bending roll force S max With the minimum bending roll force S min Maximum flatness adjustment value between:

[0021] Where: are the maximum and minimum plate shapes corresponding to the minimum bending roll force, They are the maximum and minimum plate shapes corresponding to the maximum bending roll force respectively.

[0022] In the step (L), the maximum plate shape adjustment value in the other six cases is calculated, and the strip width is b n And the rolling pressure is q' max The maximum flatness value is ΔL when t2 , strip width is b w And the rolling pressure is q' min The maximum flatness value is ΔL when t3 , strip width is b w And the rolling pressure is q' max The maximum flatness value is ΔL when t4 , strip width is b avr And the rolling pressure is q' min The maximum flatness value is ΔL when t5 , strip width is bavr And the rolling pressure is q' max The maximum flatness value is ΔL when t6 , strip width is b avr And the rolling pressure is q' avr The maximum flatness value is ΔL when t7 :

[0023] In the step (M), the maximum plate shape adjustment value under a specific rack is calculated: ΔL t =min{ΔL tk}, k=1,2,...,7, the plate shape adjustment range under the specific stand of the output four-high CVC hot rolling mill is (0, ΔL t ).

[0024] The beneficial effects of the present invention are: considering the plate shape control process of the bending rolls of the specific frame of the four-roll CVC hot rolling mill group on the strip, by controlling the bending roll force of the specific frame of the hot rolling mill group, the plate shape of the strip when it is at the narrowest, widest and average width, and when the rolling pressure is at the maximum, minimum and average value, and the plate shape adjustment domain under the working condition is calculated, thereby realizing the evaluation of the plate shape control capability of the hydraulic bending roll control technology of the specific frame of the four-roll CVC hot rolling mill group, improving the plate shape control capability of the CVC hot rolling mill group strip under the specific frame, and bringing better economic benefits to on-site strip production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a flow chart of the present invention;

[0026] Figure 2 This is the image of the plate shape adjustment domain finally obtained in Example 1 of the present invention;

[0027] Figure 3 This is the image of the plate shape adjustment domain finally obtained in Example 2 of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the invention implementation cases clearer, the technical solutions in the invention implementation cases will be clearly and completely described below in conjunction with the drawings in the implementation cases. Obviously, the implementation cases described are only a small part of the implementation cases of the present invention, rather than all the implementation cases. Based on the implementation cases in the present invention, all other implementation cases obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] A method for evaluating the plate shape control capability comprises the following steps: (A) collecting equipment and process parameters of a four-roll CVC hot rolling mill; (B) collecting strip-related parameters; (C) dividing the roll length and the strip length; (D) calculating some parameter values required for subsequent plate shape calculation; (E) calculating the bending roll force S as the minimum bending roll force S min The corresponding support force P in this case; (F) Calculate the influence function a of the deflection of the working roll and support roll in the i-th section caused by the load in the j-th section ij 、b ij , the influence coefficient of left and right bending roller force and support force on the deflection of segment i (G) Calculate the deformation coordination equation; (H) Calculate the outlet thickness h i and working roll deflection f wi ; (I) Calculate the bending roll force S as the maximum bending roll force S min (J) Judgement: Is it established? If not, let Go to step (D); if established, go to step (K); (K) calculate the maximum plate shape adjustment value; (L) similarly calculate the maximum plate shape adjustment value in the other six cases; (M) output the plate shape adjustment range under the specific frame of the four-roll CVC hot rolling mill.

[0030] In the step (A), the equipment and process parameters of the four-high CVC hot rolling mill include the working roll diameter D of the specific stand. w , support roller diameter D b , support roller body length L b , average value of post-tension and pre-tension The influence coefficient k of the front and rear tensile stress on the rolling force r , total rolling pressure q roll , the minimum, maximum and average total rolling pressure q' under a specific stand min ,q' max ,q' avr , minimum bending roll force S min , maximum bending roll force S max , bending roll force arm and support force arm

[0031] In the step (B), the strip parameters include the actual strip width b, the strip elastic modulus and Poisson's ratio E, ν, the average strip inlet thickness H, the average strip outlet thickness h, the strip deformation resistance σ, and the narrowest, widest and average strip width b under a specific frame. n 、b w 、b avr .

[0032] In the step (C), the length of the support roll is divided into n2 parts, and the generalized rolling pressure is also divided into n2 parts, wherein the non-zero part of the rolling pressure contains n1 parts. For the convenience of calculation, n2 is written as 2n+1, and n1 is written as 2m+1, and i,j∈{1,2,...,2n+1}, the plate shape calculation iterative error ε, the work roll deflection influence function a of the specific stand ij , support roller deflection influence function b ij , left and right bending roll force deflection influence function Left and right support force deflection influence function The pressure value q between the rollers in the jth section j , rolling pressure value q' in the jth section j , the rigid rotation angle β of the working roll relative to the backup roll, ΔL tl is the maximum plate shape adjustment value between the minimum and maximum bending roll forces in the lth case (l=1,2,...,7), ΔL t It is the maximum plate shape adjustment value under the specific stand of the four-high CVC hot rolling mill.

[0033] In the step (D), the strip is considered to have a width of b=b n , the total rolling pressure is q roll =q' min , calculate some parameter values required for the subsequent plate shape calculation:

[0034] Where: x and x' are the lengths of the support roller body at the i-th and j-th positions respectively, Δx is the length of each roller body segment, x1 is the position of each segment divided by the incoming material shape, H i is the entrance thickness value of the i-th position of the divided incoming material plate shape, I w , I b are the moments of inertia of the working roll and the support roll, k1 and k2 are the coefficients of the influence functions of the working roll and the support roll, P(S) is the support force calculation function, q roll is the total rolling force for a particular stand.

[0035] In the step (E), the bending roll force S is calculated as the minimum bending roll force S min The corresponding support force in this case: P(S min )=(q roll +2×S min ) / 2.

[0036] In the step (F), the influence function a of the deflection of the working roll and the backup roll of the i-th section caused by the load of the j-th section is calculated. i 、 j b, the influence coefficient of left and right bending roller force and support force on the deflection of segment i j a.1S 、 j b1:

[0037] Where: f1( c ,k i ,x j ), x is the influence function of the load on the deflection of the roller in the i-th section, where k c is the coefficient parameter of the influence function, x i 、x j are the position parameters of the loads in the i-th and j-th sections, respectively, and D c is the roller diameter parameter.

[0038] In the step (G), the sum of the roller diameter differences ΔD between the upper and lower working rolls is given i According to the metal plastic deformation model and the roll elastic deformation model, the deformation coordination equation of the work roll and the backup roll of the specific stand of the four-high CVC hot rolling mill is listed and solved:

[0039] Where: K is the flexibility coefficient of the working roll and the backup roll flattening each other, S1 and S2 are the bending roll forces at the left and right ends of the working roll respectively, C1 and C2 are the coefficient vectors on the right side of the equation group, and q roll is the total rolling pressure for a particular stand.

[0040] In the step (H), the specific stand bending roll force of the CVC hot rolling mill is calculated as the minimum bending roll force S min , and the strip width is b n , rolling pressure is q' min The outlet thickness h i , working roll deflection f wi :

[0041] Where: K' is the flattening coefficient between the work roll and the rolled piece, is the deflection of the upper working roll, Δh i The thickness difference between the entrance and exit.

[0042] In the step (I), the specific stand bending roll force S of the CVC hot rolling mill is calculated as the minimum bending roll force S min , and the strip width is b n , rolling pressure is q' min Similarly, according to the previous steps, the bending roll force S can be calculated as the maximum bending roll force S max Plate shape at:

[0043] Where: The strip width is b n, rolling pressure is q' min When the minimum bending roll force S min and maximum bending roll force S max The following flatness value.

[0044] In the step (J), ε is the calculated error of the plate shape of a specific stand of the CVC hot rolling mill, and it is determined that: Is i=n-m+1,...,n+m+1? If not, let i=n-m+1,...,n+m+1, go to step (D); if established, go to step (K).

[0045] In the step (K), the minimum bending roll force S is calculated respectively. min and maximum bending roll force S max The plate shape value and calculate the maximum bending roll force S max With the minimum bending roll force S min Maximum flatness adjustment value between:

[0046] Where: are the maximum and minimum plate shapes corresponding to the minimum bending roll force, They are the maximum and minimum plate shapes corresponding to the maximum bending roll force respectively.

[0047] In the step (L), the maximum plate shape adjustment value in the other six cases is calculated, and the strip width is b n And the rolling pressure is q' max The maximum flatness value is ΔL when t2 , strip width is b w And the rolling pressure is q' min The maximum flatness value is ΔL when t3 , strip width is b w And the rolling pressure is q' max The maximum flatness value is ΔL when t4 , strip width is b avr And the rolling pressure is q' min The maximum flatness value is ΔL when t5 , strip width is b avr And the rolling pressure is q' max The maximum flatness value is ΔL when t6 , strip width is b avr And the rolling pressure is q' avr The maximum flatness value is ΔL when t7 :

[0048] In the step (M), the maximum plate shape adjustment value under a specific rack is calculated: ΔL t =min{ΔLtk}, k=1,2,...,7, the plate shape adjustment range under the specific stand of the output four-high CVC hot rolling mill is (0, ΔL t ).

[0049] Example 1: The steel grade is 700L, and the specifications are 1600 mm × 16.79 mm (width × thickness).

[0050] In order to achieve the above objectives, the present invention adopts the following technical solutions:

[0051] First, in step (A), the equipment and process parameters of the four-high CVC hot rolling mill are collected: the working roll diameter D of the specific stand w =800mm, support roller diameter D b =1500mm, support roller body length L b =2050mm, average value of rear tension and front tension The influence coefficient k of the front and rear tensile stress on the rolling force r =0.03966, minimum, maximum and average rolling pressure q' under a specific stand min =1200t,q' max =1800t,q' avr =1500t, bending roll force arm Support force arm Given the sum of the roller diameter difference ΔD between the upper and lower working rolls i =[-0.0005 -0.0281 -0.0524 -0.0736 -0.0918 -0.1070 -0.1196 -0.1296 -0.1372 -0.1424 -0.1455 -0.1466 -0.1458 -0.1433 -0.1392 -0.1336 -0.1268 -0.1188 -0.1098 -0.0998 -0.0892 -0.0780 -0.0663 -0.0543 -0.0421 -0.0299 -0.0178 -0.0060 0.00540.0163 0.0265 0.0358 0.0442 0.0515 0.0575 0.0622 0.0653 0.0667 0.0663]mm;

[0052] Then, in step (B), the relevant parameters of the strip are collected: the actual strip width b = 1500 mm, the strip elastic modulus and Poisson's ratio E = 210000 MPa, ν1 = 0.3, the average strip inlet thickness H = 27.52 mm, the average strip outlet thickness h = 16.79 mm, the strip deformation resistance σ = 151.7 MPa, the narrowest, widest and average strip widths b under the specific standn =1400mm,b w =1600mm,b avr =1500mm;

[0053] Then, in step (C), the length of the support roll is divided into n2=41 parts, and the generalized rolling pressure is also divided into n2 parts, where the non-zero part of the rolling pressure contains n1=31 parts. For the convenience of calculation, n2 is written as 2n+1, then n=20, and n1 is written as 2m+1, then m=15, and i, j∈{1,2,...,2n+1}, and the given plate shape calculation iteration error ε=0.005;

[0054] Then in step (D), consider the strip when the strip has an average width b n =1500mm, average rolling pressure is q roll =q' aver =1200t, calculate some parameter values required for the subsequent plate shape calculation:

[0055] The calculated inlet thickness distribution is H i =[27.4596 27.4717 27.4830 27.4934 27.5029 27.5117 27.5196 27.5267 27.5329 27.5383 27.5429 27.5466 27.5496 27.5516 27.5529 27.5533 27.5529 27.5516 27.5496 27.5466 27.5429 27.5383 27.5329 27.5267 27.5196 27.5117 27.5029 27.4934 27.4830 27.4717 27.4596]mm;

[0056] Then in step (E), the bending roll force S is calculated as the minimum bending roll force, the maximum bending roll force S min 、S max The plate shape at this time, first calculate the bending roll force S as the minimum bending roll force S min =The corresponding support force under the condition of 65t: P(S min )=(q roll +2×S min ) / 2, and calculate P(S min )=815t;

[0057] Then, in step (F), the influence function a of the deflection of the working roll and the backup roll of the i-th section caused by the load of the j-th section is calculated. ij 、b ij, the influence coefficient of left and right bending roller force and support force on the deflection of segment i

[0058] Considering that the result of the influence coefficient matrix is a large matrix, only the influence coefficient results of the left bending roll force and the left support force on the j-segment roll deflection are listed here.

[0059]

[0060] Then, in step (G), based on the metal plastic deformation model and the roll system elastic deformation model, the deformation coordination equation of the work rolls and backup rolls of the specific stand of the four-high CVC hot rolling mill is listed and solved:

[0061] Calculate the roller pressure q j =[492316 472929 456090 441758 429871 420350 411590403547 396185 389478 383401 377937 373073 368798 365103 361984 359436 357456356044 355196 354914 355196 356044 357456 359436 361984 365103 368798 373073377937 383401 389478 396185 403547 411590 420350 429871 441758 456090 472929492316]N, rolling pressure q' j =[580187 562796 545882 529638 514229 499795 486452474298 463414 453865 445706 438977 433712 429934 427662 426903 427662 429934433712 438977

[0062] 445706 453865 463414 474298 486452 499795 514229 529638 545882 562796580187]N;

[0063] Then, in step (H), the specific stand bending force of the CVC hot rolling mill is calculated as the minimum bending force Smin , and the strip width is b n , rolling pressure is q' min The outlet thickness h i , working roll deflection f wi :

[0064]

[0065] Calculate the outlet thickness h i =

[0066] 16.7530 16.7604 16.7673 16.7737 16.7795 16.7849 16.7897 16.7941 16.7979 16.8012 16.8040 16.8063 16.8081 16.8094 16.8102 16.8104 16.8102 16.8094 16.8081 16.8063 16.8040 16.8012 16.7979 16.7941 16.7897 16.7849 16.7795 16.7737 16.7673 16.7604 16.7530]mm, working roll deflection f wi =[0.2065 0.2077 0.2035 0.1941 0.1796 0.1604 0.1417 0.1237 0.1065 0.0903 0.0752 0.0613 0.0487 0.0375 0.0277 0.0193 0.0124 0.0070 0.0031 0.0008 0.0000 0.0008 0.0031 0.0070 0.0124 0.0193 0.0277 0.0375 0.0487 0.0613 0.0752 0.0903 0.1065 0.1237 0.14170.1604 0.1796 0.1941 0.2035 0.2077 0.2065]mm;

[0067] Then in step (I), the CVC hot rolling mill specific stand bending roll force S is calculated as the minimum bending roll force S min , and the strip width is b n , rolling pressure is q' min Similarly, according to the previous steps, the bending roll force S can be calculated as the maximum bending roll force S max Plate shape at:

[0068]

[0069] Calculated

[0070]

[0071] Then in step (J), ε is the calculated error of the plate shape of the specific stand of the CVC hot rolling mill, i=n-m+1,...,n+m+1 holds, go to step (K);

[0072] Then in step (K), the minimum bending roll force S is calculated respectively. min and maximum bending roll force S max The plate shape value and calculate the maximum bending roll force S max With the minimum bending roll force S min Maximum flatness adjustment value between:

[0073]

[0074] Calculate ΔL t1 =9.64I;

[0075] Then in step (L), the maximum flatness adjustment value in the other six cases is calculated, and the strip width is b n And the rolling pressure is q' max The maximum flatness value is ΔL when t2 , strip width is b w And the rolling pressure is q' min The maximum flatness value is ΔL when t3 , strip width is b w And the rolling pressure is q' max The maximum flatness value is ΔL when t4 , strip width is b avr And the rolling pressure is q' min The maximum flatness value is ΔL when t5 , strip width is b avr And the rolling pressure is q' max The maximum flatness value is ΔL when t6 , strip width is b avr And the rolling pressure is q' avr The maximum flatness value is ΔL when t7 :

[0076] Calculate ΔL t2 =9.82,ΔL t3 =8.43I,ΔL t4 =8.61I,ΔL t5 =9.00I,ΔL t6 =9.19I,ΔL t7 =9.31I;

[0077] Finally, in step (M), the maximum plate shape adjustment value under a specific rack is calculated: ΔL t =min{ΔL tk}, k=1,2,...,7, calculate ΔL t =8.43I, then the final plate shape adjustment range under the specific stand of the four-high CVC hot rolling mill is (0,8.43):

[0078] The image of the plate shape adjustment area under the specific frame of the four-roller CVC unit finally obtained in this embodiment is as follows Figure 2 .

[0079] Example 2: The steel type is SPHC-S, and the specifications are 1600 mm×6.69 mm (width×thickness).

[0080] In order to achieve the above objectives, the present invention adopts the following technical solutions:

[0081] First, in step (A), the equipment and process parameters of the four-high CVC hot rolling mill are collected: the working roll diameter D of the specific stand w =750mm, support roller diameter D b =1400mm, support roller body length L b =1950mm, average value of rear tension and front tension The influence coefficient k of the front and rear tensile stress on the rolling force r =0.03966, minimum, maximum and average rolling pressure q' under a specific stand min =1000t,q' max =1600t,q' avr =1300t, bending roll force arm Support force arm Given the sum of the roller diameter difference ΔD between the upper and lower working rolls i =[-0.0005 -0.0281 -0.0524 -0.0736 -0.0918 -0.1070 -0.1196 -0.1296 -0.1372 -0.1424 -0.1455 -0.1466 -0.1458 -0.1433 -0.1392 -0.1336 -0.1268 -0.1188 -0.1098 -0.0998 -0.0892 -0.0780 -0.0663 -0.0543 -0.0421 -0.0299 -0.0178 -0.0060 0.0054 0.0163 0.0265 0.0358 0.0442 0.0515 0.0575 0.0622 0.0653 0.0667 0.0663]mm;

[0082] Then, in step (B), the relevant parameters of the strip are collected: the actual strip width b = 1600 mm, the strip elastic modulus and Poisson's ratio E = 210,000 MPa, ν1 = 0.3, the average strip inlet thickness H = 8.66 mm, the average strip outlet thickness h = 6.69 mm, the strip deformation resistance σ = 257 MPa, the narrowest, widest and average strip widths b under the specific stand n =1300mm,b w =1600mm,b avr =1900mm;

[0083] Then, in step (C), the length of the support roll is divided into n2=39 parts, and the generalized rolling pressure is also divided into n2 parts, where the non-zero part of the rolling pressure contains n1=33 parts. For the convenience of calculation, n2 is written as 2n+1, then n=19, and n1 is written as 2m+1, then m=16, and i, j∈{1,2,...,2n+1}, and the given plate shape calculation iteration error ε=0.005;

[0084] Then in step (D), consider the strip when the strip has an average width b n =1500mm, average rolling pressure is q roll =q' aver =1300t, calculate some parameter values required for the subsequent plate shape calculation:

[0085] The calculated inlet thickness distribution is H i =[8.5993 8.6107 8.6213 8.6312 8.6404 8.64898.6566 8.6636 8.6698 8.6753 8.6801 8.6841 8.6874 8.6900 8.6918 8.6929 8.69338.6929 8.6918 8.6900 8.6874 8.6841 8.6801 8.6753 8.6698 8.6636 8.6566 8.64898.6404 8.6312 8.6213 8.6107 8.5993]mm;

[0086] Then in step (E), the bending roll force S is calculated as the minimum bending roll force, the maximum bending roll force S min 、S max The plate shape at this time, first calculate the bending roll force S as the minimum bending roll force S min =The corresponding support force under the condition of 65t: P(S min )=(q roll +2×S min) / 2, and calculate P(S min )=715t;

[0087] Then, in step (F), the influence function a of the deflection of the working roll and the backup roll of the i-th section caused by the load of the j-th section is calculated. ij 、b ij , the influence coefficient of left and right bending roller force and support force on the deflection of segment i

[0088] Considering that the result of the influence coefficient matrix is a large matrix, only the influence coefficient results of the left bending roll force and the left support force on the j-segment roll deflection are listed here.

[0089]

[0090] Then, in step (G), based on the metal plastic deformation model and the roll system elastic deformation model, the deformation coordination equation of the work rolls and backup rolls of the specific stand of the four-high CVC hot rolling mill is listed and solved:

[0091] Calculate the roller pressure q j =[493464 469103 447854 429645 413036 397925 384221371839 360704 350747 341907 334132 327375 321596 316761 312842 309817 307669306384 305957 306384 307669 309817 312842 316761 321596 327375 334132 341907350747 360704 371839 384221 397925 413036 429645 447854 469103 493464]N; rolling pressure q' j=[414742 415303 414343 412178 409098 405365 401215 396859 392485388255 384312 380777 377750 375313 373528 372440 372074 372440 373528 375313377750 380777 384312 388255 392485 396859 401215 405365 409098 412178 414343415303 414742]N;

[0092] Then, in step (H), the specific stand bending force of the CVC hot rolling mill is calculated as the minimum bending force S min , and the strip width is b n , rolling pressure is q' min The outlet thickness h i , working roll deflection f wi :

[0093]

[0094] Calculate the outlet thickness h i =[6.6431 6.6519 6.6601 6.6678 6.6749 6.6814 6.68746.6927 6.6976 6.7018 6.7055 6.7086 6.7112 6.7132 6.7146 6.7154 6.7157 6.71546.7146 6.7132 6.7112 6.7086 6.7055 6.7018 6.6976 6.6927 6.6874 6.6814 6.67496.6678 6.6601 6.6519 6.6431]mm; working roll deflection f wi=[0.06850 0.07791 0.08136 0.07911 0.07528 0.07020 0.06420 0.05756 0.05055 0.04340 0.03633 0.02953 0.02316 0.01737 0.01226 0.00796 0.00452 0.00202 0.00051 0.00000 0.00051 0.00202 0.00452 0.00796 0.01226 0.01737 0.02316 0.02953 0.03633 0.04340 0.050550.05756 0.06420 0.07020 0.07528 0.07911 0.08136 0.07791 0.06850]mm

[0095] Then in step (I), the CVC hot rolling mill specific stand bending roll force S is calculated as the minimum bending roll force S min , and the strip width is b n , rolling pressure is q' min Similarly, according to the previous steps, the bending roll force S can be calculated as the maximum bending roll force S max Plate shape at:

[0096]

[0097] Calculated

[0098]

[0099] Then in step (J), ε is the plate shape calculation error of the specific stand of the CVC hot rolling mill, given ε = 0.005, i=n-m+1,...,n+m+1 holds, go to step (K);

[0100] Then in step (K), the minimum bending roll force S is calculated respectively. min and maximum bending roll force S max The plate shape value and calculate the maximum bending roll force S max With the minimum bending roll force S min Maximum flatness adjustment value between:

[0101]

[0102] Calculate ΔL t1 =8.68I;

[0103] Then in step (L), the maximum flatness adjustment value in the other six cases is calculated, and the strip width is bn And the rolling pressure is q' max The maximum flatness value is ΔL when t2 , strip width is b w And the rolling pressure is q' min The maximum flatness value is ΔL when t3 , strip width is b w And the rolling pressure is q' max The maximum flatness value is ΔL when t4 , strip width is b avr And the rolling pressure is q' min The maximum flatness value is ΔL when t5 , strip width is b avr And the rolling pressure is q' max The maximum flatness value is ΔL when t6 , strip width is b avr And the rolling pressure is q' avr The maximum flatness value is ΔL when t7 :

[0104] Calculate ΔL t2 =17.45I,ΔL t3 =5.91I,ΔL t4 =9.27I,ΔL t5 =7.03I,ΔL t6 =14.15I,ΔL t7 =13.06I,;

[0105] Finally, in step (M), the maximum plate shape adjustment value under a specific rack is calculated: ΔL t =min{ΔL tk}, k=1,2,...,7, calculate ΔL t =5.91I, then the final plate shape adjustment range under the specific stand of the four-high CVC hot rolling mill is (0, 5.91).

[0106] The image of the plate shape adjustment area under the specific frame of the four-roller CVC unit finally obtained in this embodiment is as follows Figure 3 .

Claims

1. A method for evaluating flatness control capability, characterized in that The method comprises the following steps: (A) collecting equipment and process parameters of a four-high CVC hot rolling mill; (B) collecting strip steel related parameters; (C) dividing the roll length and the plate strip length; (D) Calculate the parameter values required for the subsequent plate shape calculation; (E) Calculate the bending roll force S as the minimum bending roll force S min The corresponding support force P(S min ); (F) Calculate the influence function a of the deflection of the working roll and support roll in section i caused by the load in section j ij 、b ij , the influence coefficients of the left and right bending roller forces and the left and right supporting forces on the deflection of segment i (G) Calculate the deformation coordination equation; (H) Calculate the outlet thickness h i and upper work roll deflection (I) Calculate the bending roll force S as the maximum bending roll force S max and minimum bending roll force S min Plate shape when (J) Judgment: Is it established? If not, let Go to step (D); if so, go to step (K); (K) calculate the maximum flatness adjustment value; (L) similarly calculate the maximum flatness adjustment values for the other six cases; (M) output the flatness adjustment range under the specific stand of the four-high CVC hot rolling mill; In the step (A), the equipment and process parameters of the four-high CVC hot rolling mill include the working roll diameter D of the specific stand. w , support roller diameter D b , support roller body length L b , average value of post-tension and pre-tension The influence coefficient k of the front and rear tensile stress on the rolling force r , total rolling pressure q roll , the minimum, maximum and average total rolling pressure q' under a specific stand min ,q' max ,q' avr , minimum bending roll force S min , maximum bending roll force S max , bending roll force arm and support force arm In the step (B), the strip parameters include the actual strip width b, the strip elastic modulus and Poisson's ratio E, ν, the average strip inlet thickness H, the average strip outlet thickness h, the strip deformation resistance σ, and the narrowest, widest and average strip width b under a specific frame. n 、b w 、b avr ; In the step (C), the length of the support roll is divided into n2 parts, and the generalized rolling pressure is also divided into n2 parts, wherein the non-zero part of the rolling pressure contains n1 parts. For the convenience of calculation, n2 is written as 2n+1, and n1 is written as 2m+1, and i,j∈{1,2,...,2n+1}, the plate shape calculation iterative error ε, and the influence function a of the deflection of the i-segment work roll caused by the j-segment load of a specific stand ij , the influence function b of the support roller deflection of the i-th segment caused by the j-th segment load ij , Influence function of left and right bending roller forces on segment i deflection Influence function of left and right support forces on segment i deflection The pressure value q between the rollers in the jth section j , rolling pressure value q' in the jth section j , the rigid rotation angle β of the working roll relative to the backup roll, ΔL tl is the maximum plate shape adjustment value between the minimum and maximum bending roll forces in the lth case (l=1,2,...,7), ΔL t It is the maximum plate shape adjustment value under the specific stand of the four-high CVC hot rolling mill; In the step (E), the bending roll force S is calculated as the minimum bending roll force S min The corresponding support force in this case: P(S min )=(q roll +2×S min ) / 2; In the step (H), the bending roll force of the specific stand of the CVC hot rolling mill is calculated as the minimum bending roll force S min , and the strip width is b n , rolling pressure is q' min The outlet thickness h i , upper working roll deflection Where: K' is the flattening coefficient between the work roll and the rolled piece, is the deflection of the upper working roll, Δh i The thickness difference between the entrance and exit; In the step (I), the specific stand bending roll force S of the CVC hot rolling mill is calculated as the minimum bending roll force S min , and the strip width is b n , rolling pressure is q' min Similarly, according to the previous steps, the bending roll force S can be calculated as the maximum bending roll force S max Plate shape at: Where: The strip width is b n , rolling pressure is q' min When the minimum bending roll force S min and maximum bending roll force S max The plate shape value under ; In the step (K), the minimum bending roll force S is calculated respectively. min and maximum bending roll force S max The plate shape value and calculate the maximum bending roll force S max With the minimum bending roll force S min Maximum flatness adjustment value between: Where: are the maximum and minimum plate shapes corresponding to the minimum bending roll force, are the maximum and minimum plate shapes corresponding to the maximum bending roll force respectively; In the step (L), the maximum plate shape adjustment value in the other six cases is calculated, and the strip width is b n And the rolling pressure is q' max The maximum plate shape adjustment value is ΔL t2 , strip width is b w And the rolling pressure is q' min The maximum plate shape adjustment value is ΔL t3 , strip width is b w And the rolling pressure is q' max The maximum plate shape adjustment value is ΔL t4 , strip width is b avr And the rolling pressure is q' min The maximum plate shape adjustment value is ΔL t5 , strip width is b avr And the rolling pressure is q' max The maximum plate shape adjustment value is ΔL t6 , strip width is b avr And the rolling pressure is q' avr The maximum plate shape adjustment value is ΔL t7 :

2. The method for evaluating flatness control capability according to claim 1, wherein: In the step (D), the strip is considered to have a width of b=b n , the total rolling pressure is q roll =q' min , calculate the parameter values required for the subsequent plate shape calculation: Where: x and x' are the lengths of the support roller body at the i-th and j-th positions respectively, Δx is the length of each roller body segment, x1 is the position of each segment divided by the incoming material shape, H i is the entrance thickness value of the i-th position of the divided incoming material plate shape, I w , I b are the inertia moments of the working roll and the backup roll, respectively; k1 and k2 are the coefficients of the influence functions of the working roll and the backup roll, respectively; q roll is the total rolling force for a particular stand.

3. The method for evaluating flatness control capability according to claim 2, wherein: In the step (F), the influence function a of the deflection of the working roll and the backup roll of the i-th section caused by the load of the j-th section is calculated. ij 、b ij , the influence function of the left and right bending roller forces and the left and right supporting forces on the deflection of segment i Where: f1(k c ,x i ,x j ,D c ) is the influence function of the load on the deflection of the roller in the i-th section, where k c is the coefficient parameter of the influence function, x i 、x j are the position parameters of the loads in the i-th and j-th sections, respectively, and D c is the roller diameter parameter.

4. The method for evaluating flatness control capability according to claim 1, wherein: In the step (G), the sum of the roller diameter differences ΔD between the upper and lower working rolls is given i According to the metal plastic deformation model and the roll elastic deformation model, the deformation coordination equation of the work roll and the backup roll of the specific stand of the four-high CVC hot rolling mill is listed and solved: Where: K is the flexibility coefficient of the working roll and the backup roll flattening each other, S1 and S2 are the bending roll forces at the left and right ends of the working roll respectively, C1 and C2 are the coefficient vectors on the right side of the equation group, and q roll is the total rolling pressure for a particular stand.

5. The method for evaluating flatness control capability according to claim 1, wherein: In the step (J), ε is the iterative error of the plate shape calculation of the specific stand of the CVC hot rolling mill, and it is determined that: Is i=n-m+1,...,n+m+1? If not, let i=n-m+1,...,n+m+1, go to step (D); if established, go to step (K).

6. The method for evaluating flatness control capability according to claim 1, wherein: In the step (M), the maximum plate shape adjustment value under a specific rack is calculated: ΔL t =min{ΔL tk }, k=1,2,...,7, the plate shape adjustment range under the specific stand of the output four-high CVC hot rolling mill is (0, ΔL t ).

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