A method for obtaining reduction ratios of a continuous rolling mill unit that can coordinate rolling pressures of each stand

Abstract

A method for obtaining the reduction ratio of a continuous rolling mill unit that can coordinate the rolling pressure of each stand, including: inputting process parameters and continuous rolling mill equipment parameters; setting the rolling pressure ratio φ of each stand to the first stand k , and establishing the rolling pressure coordination optimization objectives and constraints for each stand; initially setting the reduction ratio of each stand using an optimization algorithm; calculating the entrance thickness and exit thickness of the rolled piece for each stand; calculating the rolling force and energy parameters of each stand, where the rolling force and energy parameters of each stand include the rolling pressure, transmission torque, forward slip value, roll speed, and main motor power of each stand; determining whether the rolling pressure coordination optimization objectives and constraints for each stand are simultaneously satisfied. The present invention can be used for online preset calculation of the reduction ratio distribution of a continuous rolling mill unit, and the calculated reduction ratio distribution can achieve the distribution of the rolling pressure of each stand according to the set ratio, which is used to effectively adjust the plate crown and achieve the purpose of precisely controlling the strip shape.

Description

Technical Field

[0001] This embodiment relates to the field of rolling, and particularly to a method for obtaining the reduction ratio of a tandem mill unit that can coordinate the rolling pressures of each stand. Background Art

[0002] In the production process of strip tandem rolling, the distribution of the reduction ratio of each stand of the tandem mill is one of the most important tandem rolling process parameters, which directly determines the stability and smooth progress of the production process and is also a basic parameter for the control of the thickness and shape of the rolled piece. The existing technology often uses the method of setting by manual experience table to distribute the reduction ratio of each stand of the tandem mill. The establishment of this experience table requires a large amount of production practice data and operation experience in the early stage. When the product specifications are changed, it takes a long time to re - establish the new table data, and it cannot perform real - time online preset calculation for the distribution of the reduction ratio according to the new product specifications. In addition, there is no evaluation standard for the table data for comparison. For example, it is impossible to distribute the rolling pressures of each stand according to a predetermined ratio, resulting in the given tandem rolling reduction ratio distribution being unable to effectively adjust the plate crown. Therefore, it is necessary to further develop a method for obtaining the reduction ratio of a tandem mill unit that can coordinate the rolling pressures of each stand.

[0003] Content of the embodiment

[0004] In view of the above problems, this embodiment is proposed to provide a method for obtaining the reduction ratio of a tandem mill unit that can overcome or at least partially solve the above problems and can coordinate the rolling pressures of each stand.

[0005] In order to solve the above technical problems, the embodiments of the present application disclose the following technical solutions:

[0006] A method for obtaining the reduction ratio of a tandem mill unit that can coordinate the rolling pressures of each stand, comprising:

[0007] S100. Input process parameters and tandem mill equipment parameters;

[0008] S200. Set the ratio φ k of the rolling pressure of each stand to the first stand, and establish the coordinated optimization objective and constraint conditions for the rolling pressures of each stand;

[0009] S300. Use an optimization algorithm to initially set the reduction ratios η1, η2... η Q-1 of the first stand to the (Q - 1)th stand;

[0010] S400. Calculate the inlet thickness and outlet thickness of the rolled piece for each stand;

[0011] S500. Calculate the rolling force and energy parameters of each stand, where the rolling force and energy parameters of each stand include the rolling pressure, transmission torque, forward slip value, roll speed, and main motor power of each stand;

[0012] S600. Determine whether the rolling pressure coordination optimization objectives and constraint conditions of each stand are satisfied simultaneously: If not, adjust the reduction ratio values of each stand by the optimization algorithm, and then transfer to S400 for recalculation. If satisfied, the calculation ends.

[0013] Further, in S100, the process parameters include the incoming material thickness H (unit: mm), the finished product thickness h (unit: mm), the width B s (unit: mm) of the rolled piece, the number of stands Q, and the data of the deformation resistance of the rolled piece. The equipment parameters of the tandem mill include the working roll body diameter D wk (unit: mm), the working roll neck diameter D′ wk (unit: mm), the working roll body width B wk (unit: mm), the backup roll body diameter D bk (unit: mm), the backup roll neck diameter D′ bk (unit: mm), and the backup roll body width B bk (unit: mm), where the subscript k represents the stand number, and 1 ≤ k ≤ Q.

[0014] Further, in S200, the objective function of the rolling pressure coordination optimization objective of each stand is:

[0015] In the formula, P1 is the rolling pressure of the first stand (the leading stand), unit: KN, and P k is the rolling pressure of the kth stand, unit: KN.

[0016] Further, in S400, calculate the incoming thickness h 0k and the outgoing thickness h 1k of the rolled piece in each stand. Specifically: When k = 1, h 0k = H, h 1k = (1 - η k )H; When 2 ≤ k ≤ Q - 1, h 0k = h 1(k-1) , h 1k = (1 - η k )h 0k ; When k = Q, h 0k = h 1(k-1) , h 1k = h; The subscript k represents the stand number, 1 ≤ k ≤ Q, and η k is the reduction ratio of the kth stand.

[0017] Further, in S500, calculate the rolling force energy parameters of each stand. The specific steps are as follows:

[0018] S501. By repeatedly iterating the stress differential equation and roll gap thickness equation in the roll gap deformation zone, the unit pressure distribution, frictional stress distribution, and roll gap thickness distribution in the roll gap deformation zone are calculated;

[0019] S502. Calculate the rolling pressure P k (unit: KN), the driving torque M k (unit: KN×m), and the forward slip value f k ;

[0020] S503. Calculate the roll speed v k (unit: m / min) and the main motor power N k (unit: KW).

[0021] Furthermore, the specific steps of S501 are as follows:

[0022] S5011. Set the initial roll profile curve and determine the entrance position of the rolled piece;

[0023] S5012. Calculate the unit pressure and frictional stress of each section in the back slip zone from the entrance to the exit

[0024] S5013. Calculate the unit pressure and frictional stress of each section in the forward slip zone from the exit to the entrance;

[0025] S5014. Determine the unit pressure and frictional stress of each section in the roll gap deformation zone;

[0026] S5015. Calculate the roll gap thickness distribution from the unit pressure distribution;

[0027] S5016. Judge whether the roll gap thickness distributions obtained from the previous and current calculations converge: If they converge, end the calculation; if not, go to step S5012 for the next round of iterative calculation until the roll gap thickness distribution converges.

[0028] Furthermore, in S502, when calculating the rolling pressure P k (unit: KN), the driving torque M k (unit: KN×m), and the forward slip value f k , the specific calculation formulas are as follows:

[0029]

[0030]

[0031]

[0032] In the formula, n k is the number of discrete segments of the roll gap of the k-th stand, ΔX k is the length of the discrete segment of the roll gap of the k-th stand, unit: mm, p k(i) is the unit pressure of the i-th segment of the roll gap of the k-th stand, in MPa, t k (i) is the friction stress of the i-th segment of the roll gap of the k-th stand, in MPa, Δh k (i) is the thickness difference between the (i + 1)-th segment and the i-th segment of the roll gap of the k-th stand, in mm, Δh k (i) = h k (i + 1)-h k (i), x k (i) is the abscissa of the i-th segment of the roll gap of the k-th stand, in mm, m wb is the rolling friction force arm between the work roll and the backup roll, in mm, where, E wk is the elastic modulus of the work roll, in MPa, E bk is the elastic modulus of the backup roll, in MPa, L wb is the contact length between the work roll and the backup roll, in mm, when B wk ≤B bk then, L wb = B wk when B wk >B bk then, L wb = B bk ; ρ bk is the friction circle radius of the backup roll bearing, in mm, where, μ′ k is the rolling friction coefficient of the backup roll bearing; h k (r) is the roll gap thickness of the corresponding segment of the neutral plane of the roll gap of the k-th stand (the r-th segment of the roll gap of the k-th stand), in mm, Δh k (r) = h k (r + 1)-h k (r).

[0033] Furthermore, in S503, calculate the roll speed v k (unit: m / min) and the main motor power N k (unit: KW), the specific steps are as follows:

[0034] S5031. Calculate the second flow rate value V k_max with the maximum roll speed v k set for each stand, and the calculation formula is: V k = h 1k v k_max (1 + f k );

[0035] S5032. Find the minimum value V Q of the second flow rate values V1 to V min of each stand, and according to the second flow rate theorem, from Vmin Calculate the roll speed v′ of each stand k , and the calculation formula is:

[0036] S5033. Calculate the main motor power N′ of each stand k , and the ratio of the main motor power N′ k to the rated power N of the main motor of this stand k_max is The calculation formula is: where M k is the transmission torque, and D wk is the diameter of the working roll body;

[0037] S5034. Find the maximum value φ ; max ;

[0038] S5035. Judge whether is greater than 1: If then limit the roll speed of each stand with , and the roll speed after limiting is the calculated roll speed of each stand, that is When then v k = v′ k ;

[0039] S5036. Calculate the main motor power N of each stand k , and the calculation formula is:

[0040] Furthermore, in S300, the reduction ratio of each stand is initially set by the optimization algorithm and the reduction ratio of each stand is adjusted by the optimization algorithm. The optimization algorithm uses the genetic algorithm or the particle swarm algorithm.

[0041] Furthermore, in S600, judge whether the rolling pressure coordination optimization objectives and constraint conditions of each stand are satisfied simultaneously. The constraint conditions are specifically that all stands simultaneously satisfy the following inequalities:

[0042] η k_min ≤ η k ≤ η k_max , v k ≤ v k_max , P k ≤ P k_max , M k ≤ M k_max , N k ≤ N k_max , where the subscript k represents the stand number, 1 ≤ k ≤ Q,; η k_max is the maximum reduction ratio of the kth stand, η k_min is the minimum reduction ratio of the kth stand, vk_max is the maximum roll speed of the k-th stand, P k_max is the maximum rolling pressure of the k-th stand, M k_max is the maximum transmission torque of the k-th stand, N k_max is the rated power of the main motor of the k-th stand.

[0043] The beneficial effects of the above technical solutions provided by the embodiments of the present invention at least include:

[0044] A method for obtaining the reduction ratio of a continuous rolling mill unit that can coordinate the rolling pressures of each stand. Through theoretical analysis, a reduction ratio distribution model of the continuous rolling mill unit with the coordination of the rolling pressures of each stand as the optimization goal is established. In the calculation process, an optimization algorithm is used to continuously obtain a more optimal reduction ratio distribution, and according to the given process parameters and equipment parameters, the rolling force and energy parameters of each stand under the corresponding reduction ratio distribution are repeatedly calculated, including rolling pressure, transmission torque, forward slip value, roll speed, and main motor power. Finally, the optimal reduction ratio distribution that meets the optimization goal and constraint conditions is obtained.

[0045] The principle of the method disclosed by the present invention is clear and definite, the iterative calculation is stable and rapid, it can be used for the online preset calculation of the reduction ratio distribution of the continuous rolling mill unit, avoiding the errors brought by the traditional manual experience table setting method, and the calculated reduction ratio distribution can realize the distribution of the rolling pressures of each stand according to the set ratio, and is used to effectively adjust the plate crown, achieving the purpose of accurately controlling the strip shape.

[0046] Next, through the drawings and embodiments, the technical solutions of this embodiment will be further described in detail. Description of the Drawings

[0047] The drawings are used to provide a further understanding of this embodiment, and constitute a part of the specification. Together with the embodiments, they are used to explain the present invention and do not constitute a limitation to this embodiment. In the drawings:

[0048] Figure 1 is the calculation flow chart of a method for obtaining the reduction ratio of a continuous rolling mill unit that can coordinate the rolling pressures of each stand in Embodiment 1;

[0049] Figure 2 is the calculation flow chart of the rolling force and energy parameters of the k-th stand in Embodiment 1;

[0050] Figure 3 is the calculation flow chart of the repeated iteration of the stress differential equation and the roll gap thickness equation in the roll gap deformation zone in Embodiment 1;

[0051] Figure 4 is the calculation flow chart of the roll speed and the main motor power in Embodiment 1;

[0052] Figure 5 In Embodiment 2, it is the curve of the fitness value varying with the number of generations of evolution during the iterative calculation using the genetic algorithm;

[0053] Figure 6 In Embodiment 2, it is the curve of the fitness value varying with the number of generations of evolution during the iterative calculation using the particle swarm algorithm. Detailed implementation manners

[0054] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully communicated to those skilled in the art.

[0055] To solve the problems existing in the prior art, this embodiment provides a method for obtaining the reduction ratio of a continuous rolling mill unit that can coordinate the rolling pressures of each stand.

[0056] Embodiment 1

[0057] A method for obtaining the reduction ratio of a continuous rolling mill unit that can coordinate the rolling pressures of each stand, such as Figure 1 , includes:

[0058] S100. Input process parameters and continuous rolling mill equipment parameters; specifically, in S100 of this embodiment, the process parameters include the incoming material thickness H (unit: mm), the finished product thickness h (unit: mm), the width B s (unit: mm) of the rolled piece, the number of stands Q, and the data of the deformation resistance of the rolled piece. The continuous rolling mill equipment parameters include the working roll body diameter D wk (unit: mm) of each stand, the working roll neck diameter D' wk (unit: mm), the working roll body width B wk (unit: mm), the backup roll body diameter D bk (unit: mm), the backup roll neck diameter D' bk (unit: mm), and the backup roll body width B bk (unit: mm), where the subscript k represents the stand number, and 1 ≤ k ≤ Q.

[0059] S200. Set the ratio φ k of the rolling pressure of each stand to that of the first stand, and establish the coordinated optimization objective and constraint conditions for the rolling pressure of each stand; in S200 of this embodiment, the objective function of the coordinated optimization objective for the rolling pressure of each stand is:

[0060] In the formula, P1 is the rolling pressure of the first stand (the first stand), in KN, P kis the rolling pressure of the k-th stand, with the unit of KN.

[0061] The constraint conditions include the maximum reduction ratio η of each stand k_max , the minimum reduction ratio η k_min , the maximum roll speed v k_max (unit: m / min), the maximum rolling pressure P k_max (unit: KN), the maximum transmission torque M k_max (unit: KN×m), and the rated power N of the main motor k_max (unit: KW).

[0062] S300. Initially set the reduction ratios η1, η2…η of the 1st stand to the (Q-1)-th stand using an optimization algorithm Q-1 ; in this embodiment S300, initially set the reduction ratios of each stand and adjust the reduction ratios of each stand by the optimization algorithm. Preferably, use the genetic algorithm or the particle swarm algorithm; the principles of the genetic algorithm and the particle swarm algorithm belong to the publicly known knowledge in the industry and will not be elaborated here.

[0063] S400. Calculate the entrance thickness and exit thickness of the rolled piece for each stand; specifically, in S400, calculate the entrance thickness h 0k and the exit thickness h 1k of the rolled piece for each stand. Specifically: when k = 1, h 0k = H, h 1k = (1 - η k )H; when 2 ≤ k ≤ Q-1, h 0k = h 1(k-1) , h 1k = (1 - η k )h 0k ; when k = Q, h 0k = h 1(k-1) , h 1k = h; the subscript k represents the stand number, 1 ≤ k ≤ Q, and η k is the reduction ratio of the k-th stand.

[0064] S500. Calculate the rolling force and energy parameters of each stand. Among them, the rolling force and energy parameters of each stand include the rolling pressure, transmission torque, forward slip value, roll speed, and main motor power of each stand;

[0065] Specifically, taking the calculation of the k-th stand as an example for illustration, as Figure 2 shown, the specific steps are:

[0066] S501. Repeatedly iterate using the stress differential equation and roll gap thickness equation in the roll gap deformation zone to calculate the unit pressure distribution, friction stress distribution, and roll gap thickness distribution in the roll gap deformation zone;

[0067] S502. Calculate the rolling pressure P k (unit: KN), the driving torque M k (unit: KN×m), and the forward slip value f k ;

[0068] S503. Calculate the roll speed v k (unit: m / min), and the main motor power N k (unit: KW).

[0069] Among them, as Figure 3 shown, S501 is specifically:

[0070] S5011. Set the initial roll profile curve and determine the entrance position of the rolled piece;

[0071] Assume that the roll is undeformed and in the shape of an arc. At this time, the roll flattening amount distribution is δ(x) = 0; Discretize the deformation zone: Divide the deformation zone into n segments along the rolling direction. The roll gap thickness model equation under the arc-shaped roll profile is where x k (i) is the abscissa of the i-th segment, h k (i) is the thickness of the rolled piece in the i-th segment, x k (n) = 0, h k (n) = h 1k , h k (1) = h 0k , so Discrete segment length x k (i) = x k (1) + (i - 1)ΔX, Δh k (i) = h k (i + 1) - h k (i).

[0072] S5012. Calculate the unit pressure and friction stress of each segment in the post-slip zone from the entrance to the exit; Specifically:

[0073] Use the post-slip zone formula to calculate from the entrance to the exit, and judge the partition situation between sliding friction and sticking friction:

[0074] Calculate the unit pressure p k (1) b _sli at the entrance segment (the 1st segment) under sliding friction conditions is:

[0075]

[0076] In the formula, K k (1) is the deformation resistance of the rolled piece in the 1st segment of the roll gap, unit: MPa, μ k is the roll gap friction coefficient of the k-th stand;

[0077] Then, use the Aitken iterative method to solve for p k (1) b _sli;

[0078] Judge μ at the entrance section k p k (1) b _sli and size, and divide it into two cases:

[0079] (i) If It indicates that the entrance section is sliding friction, and the unit pressure p of the entrance section k (1) b = p k (1) b _sli. Use the stress differential equation in the back slip zone under sliding friction conditions to calculate the unit pressure of the second section, the third section... the nth section in turn, and judge μ at each section k p(i) b _sli(1 ≤ i ≤ n) and size; specifically:

[0080] The unit pressure of the (i + 1)th section in the back slip zone under sliding friction conditions is:

[0081]

[0082] The frictional stress of the ith section in the back slip zone under sliding friction conditions is: t k (i) b _sli = μ k p k (i) b _sli.

[0083] There are also two cases in the calculation process:

[0084] 1) If it satisfies from the entrance section (the first section) to the exit section (the nth section) (1 ≤ i ≤ n), it indicates that it is sliding friction from the entrance to the exit when calculating using the stress differential equation in the back slip zone under sliding friction conditions; at this time, the unit pressures of each section calculated using the back slip zone formula are: p k (1) b = p k (1) b _sli, p k (2) b = p k (2) b _sli... p k (n) b = p k (n) b _sli;

[0085] 2) If at the m-th (1 < m ≤ n) section, there is: It indicates that from the m-th section to the outlet, it is all adhesive friction; then, use the stress differential equation in the backward slip zone under the condition of adhesive friction to calculate the unit pressure of the m-th section, the (m + 1)-th section... the n-th section in sequence; specifically:

[0086] The unit pressure of the (i + 1)-th section in the backward slip zone under the condition of adhesive friction is:

[0087]

[0088] The friction stress of the i-th section in the backward slip zone under the condition of adhesive friction is:

[0089] At this time, the unit pressures of each section calculated using the backward slip zone formula are: p k (1) b = p k (1) b _sli, p k (2) b = p k (2) b _sli... p k (m - 1) b = p k (m - 1) b _sli, p k (m) b = p k (m) b _sti, p k (m + 1) b = p k (m + 1) b _sti... p k (n) b = p k (n) b _sti;

[0090] (ii) If It indicates that the inlet section is adhesive friction, and from the inlet section to the outlet section is all adhesive friction; the unit pressure of the inlet section Use the stress differential equation in the backward slip zone under the condition of adhesive friction to calculate the unit pressure of the 2nd section, the 3rd section... the n-th section in sequence; the unit pressures of each section calculated using the backward slip zone formula are p k (1) b = p k (1) b _sti, p k (2) b = p k (2) b_sti……p k (n) b = p k (n) b _sti。

[0091] S5013. Calculate the unit pressure and frictional stress of each section in the forward slip zone from the exit to the entrance; similar to the calculation method in the backward slip zone, specifically:

[0092] Use the forward slip zone formula to calculate from the exit to the entrance and determine the division of sliding friction and adhesive friction.

[0093] 1. Calculate the unit pressure p k (n) f _sli at the exit section under sliding friction conditions is:

[0094] Solve for p k (n) f _sli using the Aitken iterative method;

[0095] 2. Judge μ k p k (n) f _sli and sizes, divided into two cases:

[0096] (i) If it means that the exit section is under sliding friction, and the unit pressure p k (n) f = p k (n) f _sli; use the stress differential equation in the forward slip zone under sliding friction conditions to calculate the unit pressure of the (n - 1)th section, (n - 2)th section,... in turn, and judge μ k p k (i) f _sli (1 ≤ i ≤ n) and sizes. Specifically:

[0097] The unit pressure of the ith section in the forward slip zone under sliding friction conditions is:

[0098]

[0099] Solve for p k (i) f _sli using the Aitken iterative method.

[0100] The frictional stress of the ith section in the forward slip zone under sliding friction conditions is: t k (i) f _sli = -μ k p k(i) f _sli, where the negative sign indicates that the direction of the frictional stress in the forward slip zone is towards the entrance side (opposite to the rolling direction).

[0101] Among them, there are two situations during the calculation process:

[0102] 1) If it satisfies from the exit section to the entrance section It indicates that when calculating using the stress differential equation in the forward slip zone under sliding friction conditions, it is sliding friction from the exit to the entrance. At this time, the unit pressure of each section calculated using the forward slip zone formula is: p k (1) f = p k (1) f _sli, p k (2) f = p k (2) f _sli…p k (n) f = p k (n) f _sli;

[0103] 2) If at the s-th section (1 < s ≤ n) there is: It indicates that from the s-th section to the entrance, it is sticking friction; then switch to using the stress differential equation in the forward slip zone under sticking friction conditions to calculate the unit pressure of the s-th section, the s - 1-th section... the 1st section in sequence; specifically:

[0104] The unit pressure of the i-th section in the backward slip zone under sticking friction conditions is:

[0105]

[0106] The frictional stress of the i-th section in the backward slip zone under sticking friction conditions is:

[0107] At this time, the unit pressure of each section calculated using the forward slip zone formula is: p k (1) f = p k (1) f _sti, p k (2) f = p k (2) f _sti…p k (s) f = p k (s) f _sti, p k (s + 1) f = p k (s + 1) f _sli…p k(n) f = p k (n) f _sli;

[0108] (ii) If it indicates that the exit section is adhesive friction, and the entire section from the exit section to the entrance section is adhesive friction; the unit pressure of the exit section successively calculates the unit pressures of the (n - 1)th section, (n - 2)th section... 1st section using the stress differential equation in the back slip zone under adhesive friction conditions;

[0109] At this time, the unit pressures of each section calculated using the forward slip zone formula are p k (1) f = p k (1) f _sti, p k (2) f = p k (2) f _sti... p k (n) f = p k (n) f _sti.

[0110] S5014. Determine the unit pressure and friction stress of each section in the roll gap deformation zone;

[0111] Compare the two sets of unit pressures p k (1) f , p k (2) f ... p k (n) f and p k (1) b , p k (2) b ... p k (n) b , find the section with the smallest difference (assumed to be the rth section), then this section is the boundary section between the forward slip zone and the back slip zone (i.e., the section corresponding to the neutral plane), x k (r) = x k (1) + (r - 1)ΔX, retain p k (1) b , p k (2) b ...,, p k (r - 1) b , p k (r) b or p k (r) f , p k (r + 1)f …… k (n) f ; So far, the unit pressure distribution under the specified roll profile has been calculated, that is, p k (1) = p k (1) b 、p k (2) = p k (2) b ,……,p k (r-1) = p k (r-1) b 、p k (r) = p k (r) b or p k (r) = p k (r) f 、p k (r+1)=p k (r+1) f …… k (n) = p k (n) f , and friction stress distribution t k (1) = t k (1) b ,t k (2) = t k (2) b ……、t k (r-1) = t k (r-1) b ,t k (r) = t k (r) b or k (r) = t k (r) f ,t k (r+1)=t k (r+1) f ……t k (n) = t k (n) f ;

[0112] S5015. Calculate the roll gap thickness distribution by the unit pressure distribution;

[0113] Calculate the roll gap thickness h using unit pressure distribution k (i); However, in order to ensure convergence, a smoothing coefficient e is introduced here to make the unit pressure of each segment calculated in the previous and next two iterations change smoothly;

[0114] That is, p k m+1 (i) = ep k(i)+(1 - e)p k m (i), 0 < e < 1, p k (i) - Unit pressure of the i-th segment of the roll gap under the specified roll profile calculated; p k m (i) - Unit pressure of the i-th segment of the roll gap used in the m-th iteration; p k m+1 (i) - Unit pressure of the i-th segment of the roll gap used in the (m + 1)-th iteration;

[0115] Using the smoothed unit pressure distribution p k m+1 (i) to calculate the elastic flattening deformation amount δ(x k (j)) of the roll, and calculate the elastic flattening amount of the roll at the abscissa x k (j) by the method of cumulative summation s i is the unit pressure p k m+1 (i) corresponding abscissa, unit mm; E wk is the elastic modulus of the work roll of the k-th stand, unit MPa; v wk is the Poisson's ratio of the work roll of the k-th stand;

[0116] Then the deformed roll profile curve distribution is obtained as:

[0117]

[0118] The roll gap thickness distribution is:

[0119] In the formula, y(x k (j)) min - Ordinate corresponding to the lowest point of the deformed roll profile curve, unit mm;

[0120] S5016. Judge whether the roll gap thickness distributions obtained from the previous and current calculations converge: If they converge, end the calculation; if not, go to step S5012 for the next round of iterative calculation until the roll gap thickness distribution converges;

[0121] Corresponding to the unit pressure distribution, smooth the roll gap thickness, that is, h k m+1 (j) = eh k (j)+(1 - e)h k m (j), in the formula, h k (j) - Calculated thickness of the j-th segment of the roll gap; h k m (j) - Thickness of the j-th segment of the roll gap used in the m-th iteration;k m +1 (j) - The thickness of the j-th segment of the roll gap used in the (m + 1)-th iteration.

[0122] Using the new roll gap thickness distribution (h k m+1 (j)), re-solve the unit pressure distribution and frictional stress distribution under the roll profile in the same method as above, and iterate repeatedly until convergence; the convergence condition is: the absolute value of the difference in the roll gap thickness of each corresponding segment calculated in two consecutive times is less than the precision value, that is, |h k (j) - h k m (j)| ≤ ε × h k (j), where ε is the convergence precision coefficient.

[0123] After the iteration converges, the unit pressure distribution p k (1), p k (2), p k (3), … p k (n), the frictional stress distribution t k (1), t k (2), t k (3), … t k (n) and the roll gap thickness distribution h k (1), h k (2), h k (3), … h k (n).

[0124] In S502 of this embodiment, calculate the rolling pressure P k (unit: KN), the driving torque M k (unit: KN×m) and the forward slip value f k , and the specific calculation formulas are:

[0125]

[0126]

[0127]

[0128] In the formula, n k is the number of discrete segments of the roll gap of the k-th stand, ΔX k is the length of the discrete segment of the roll gap of the k-th stand, unit: mm, p k (i) is the unit pressure of the i-th segment of the roll gap of the k-th stand, unit: MPa, t k (i) is the frictional stress of the i-th segment of the roll gap of the k-th stand, unit: MPa, Δh k(i) is the thickness difference between the i+1th section and the ith section of the roll gap of the kth frame, in mm, Δh k (i) = h k (i+1)-h k (i), x k (i) is the horizontal coordinate of the i-th section of the roll gap of the k-th frame, in mm, m wb is the rolling friction arm between the working roll and the support roll, in mm. Among them, E wk E is the elastic modulus of the working roll, in MPa. bk is the elastic modulus of the support roller, unit: MPa, L wb The contact length between the working roll and the backup roll, in mm. wk ≤B bk When L wb =B wk , when B wk >B bk When L wb =B bk ρ bk is the friction circle radius of the support roller bearing, in mm, Among them, μ′ k is the rolling friction coefficient of the support roller bearing; h k (r) is the roll gap thickness of the k-th frame roll gap corresponding to the neutral plane (the r-th roll gap of the k-th frame), in mm, Δh k (r) = h k (r+1)-h k (r).

[0129] In S503 of this embodiment, the roller speed v is calculated. k (Unit: m / min) and main motor power N k (Unit KW), such as Figure 4 As shown, the specific steps are:

[0130] S5031, the maximum roll speed v set for each stand k_max Calculate the second flow value V k , the calculation formula is: V k =h 1k v k_max (1+f k );

[0131] S5032, find out the second flow value V1~V of each rack Q The minimum value V min , and determine V according to the second flow min Calculate the roller speed v′ of each stand k , the calculation formula is:

[0132] S5033. Calculate the main motor power N' of each stand k , as well as the main motor power N' k and the ratio of the rated power N of the main motor of this stand k_max ; The calculation formula is:

[0133] S5034. Find out the maximum value φ max ;

[0134] S5035. Judge whether it is greater than 1: If then limit the roll speed of each stand with . The limited roll speed is the calculated roll speed of each stand, that is When then v k = v' k ;

[0135] S5036. Calculate the main motor power N of each stand k , and the calculation formula is:

[0136] So far, the rolling force and energy parameters of the k-th stand have been calculated, including the rolling pressure P k (unit: KN), the transmission torque M k (unit: KN×m), the forward slip value f k , the roll speed v k (unit: m / min) and the main motor power N k (unit: KW). The calculation methods of the rolling force and energy parameters of other stands are similar to the above, and will not be elaborated here.

[0137] S600. Judge whether the rolling pressure coordination optimization objectives and constraint conditions of each stand are satisfied simultaneously: If not, adjust the reduction ratio values of each stand by the optimization algorithm, and then transfer to S400 for recalculation. If satisfied, the calculation ends.

[0138] Specifically, in S600, judge whether the rolling pressure coordination optimization objectives and constraint conditions of each stand are satisfied simultaneously. The constraint conditions are specifically that all stands simultaneously satisfy the following inequalities:

[0139] η k_min ≤η k ≤η k_max , v k ≤v k_max , P k ≤P k_max , M k ≤M k_max , Nk ≤ N k_max , where the subscript k represents the stand number, 1 ≤ k ≤ Q,; η k_max is the maximum reduction ratio of the k-th stand, η k_min is the minimum reduction ratio of the k-th stand, v k_max is the maximum roll speed of the k-th stand, P k_max is the maximum rolling pressure of the k-th stand, M k_max is the maximum transmission torque of the k-th stand, N k_max is the rated power of the main motor of the k-th stand.

[0140] A method for obtaining the reduction ratio of a tandem mill unit that can coordinate the rolling pressure of each stand. Through theoretical analysis, a reduction ratio distribution model of the tandem mill unit with the coordination of the rolling pressure of each stand as the optimization goal is established. In the calculation process, an optimization algorithm is used to continuously obtain a better reduction ratio distribution, and according to the given process parameters and equipment parameters, the rolling force and energy parameters of each stand under the corresponding reduction ratio distribution are repeatedly calculated, including rolling pressure, transmission torque, forward slip value, roll speed, and main motor power. Finally, the optimal reduction ratio distribution that meets the optimization goal and constraint conditions is obtained.

[0141] The principle of the method disclosed in this embodiment is clear and definite, the iterative calculation is stable and rapid, and it can be used for the online preset calculation of the reduction ratio distribution of the tandem mill unit, avoiding the errors caused by the traditional manual experience table setting method. Moreover, the calculated reduction ratio distribution can allocate the rolling pressure of each stand according to the set ratio, which is used to effectively adjust the plate crown and achieve the purpose of accurately controlling the strip shape.

[0142] Embodiment 2

[0143] For the sake of easy understanding, the following further illustrates with Embodiment 2. In this embodiment, the process parameters include: the incoming material thickness H = 17 mm, the finished product thickness H = 2 mm, the width of the rolled piece B s = 1600 mm, and the number of stands Q = 5. The equipment parameters are shown in Table 1. The constraint condition parameters are shown in Table 2.

[0144] Table 1 shows the equipment parameters of Embodiment 2

[0145]

[0146] Table 2 shows the constraint condition parameters of Embodiment 2

[0147]

[0148] Other parameters include: the number of segments n = 500 divided along the rolling direction in the roll gap deformation zone, the convergence precision coefficient ε of the roll gap thickness distribution = 0.001, the smoothing coefficient e = 0.3, and the density ρ of the rolled piece = 7800 kg / m 3 , the roll gap friction coefficients of each stand μ1 = μ2 = μ3 = μ4 = μ5 = 0.3, and the elastic modulus E of the work rolls of each stand w1 = E w2 = E w3 = E w4 = E w5 = 206000 MPa, and the elastic modulus E of the backup rolls of each stand b1 = E b2 = E b3 = E b4 = E b5 = 206000 MPa, and the Poisson's ratio v of the work rolls of each stand w1 = v w2 = v w3 = v w4 = v w5 = 0.3, and the rolling friction coefficients μ′1 = μ′2 = μ′3 = μ′4 = μ′5 = 0.002 of the backup roll bearings of each stand.

[0149] As shown in Table 3, the data of the deformation resistance of the rolled piece are given in the form of a data table of the deformation resistance of the rolled piece varying with the reduction ratio.

[0150] Table 3 is the data of the deformation resistance of the rolled piece

[0151]

[0152]

[0153] The deformation resistance of the rolled piece at each position of the roll gap of each stand is calculated by the linear interpolation method:

[0154] Taking the 3rd stand as an example, assuming that the calculated entrance thickness of the rolled piece of the 3rd stand is 5 mm and the exit thickness is 3.2 mm, then the total reduction ratio of the entrance rolled piece of this stand is The total reduction ratio of the exit rolled piece is Then, the deformation resistance of the entrance rolled piece of this stand can be calculated by the linear interpolation method as The deformation resistance of the exit rolled piece of this stand is

[0155] Furthermore, taking the i-th segment (1 ≤ i ≤ 500) of the roll gap of the 3rd stand as an example, the reduction ratio per pass of this stand is Assuming that the thickness h3(i) of the rolled piece in the i-th segment of the roll gap of the 3rd stand is 4 mm, then the reduction ratio of the rolled piece in the i-th segment is Furthermore, the deformation resistance of the rolled piece in the i-th section of the roll gap of the third stand can be calculated by using the linear interpolation method as follows:

[0156]

[0157] The deformation resistance of the rolled piece at each position of the roll gap of each other stand can be calculated according to the above method, which will not be elaborated here.

[0158] Specifically, in this embodiment, the optimization algorithms adopt the genetic algorithm and the particle swarm algorithm respectively. When the genetic algorithm is used as the optimization algorithm, the principle of the genetic algorithm belongs to the publicly known knowledge in the industry and will not be elaborated here. The preset rolling pressure ratios of each stand in this embodiment are: φ1∶φ2∶φ3∶φ4∶φ5 = 1∶0.9∶0.85∶0.7∶0.65. The relevant calculation parameters of the adopted genetic algorithm are: the population size is 80, the crossover probability is 0.95, the mutation probability is 0.1, the selection method is roulette wheel selection, the crossover method is single-point crossover, the maximum number of evolutionary generations is 100, and the curve of the fitness value changing with the number of evolutionary generations during the iterative calculation process is as Figure 5 shown.

[0159] The calculated reduction ratios and rolling pressures of each stand are shown in the 4th column and the 7th column of Table 4 respectively. Further, the calculated rolling pressure ratios of each stand under this reduction ratio distribution are: 24108∶21685∶20452∶16857∶15659≈1∶0.899∶0.848∶0.699∶0.65.

[0160] It can be seen that the ratio of the rolling pressures of each stand calculated in this embodiment is very close to the preset ratio, indicating that under this reduction ratio distribution condition, the rolling pressures of each stand are distributed according to the preset ratio. Since the plate crown of the rolled piece at the outlet of each stand is adapted to the rolling pressure of each stand, the plate crown of the rolled piece can be adjusted to the preset value under this rolling schedule, so as to achieve the purpose of accurately controlling the strip shape.

[0161] Table 4 Reduction ratio distribution and energy parameters of each stand calculated in Embodiment 2

[0162]

[0163] When the particle swarm algorithm is used as the optimization algorithm, the principle of the particle swarm algorithm belongs to the publicly known knowledge in the industry and will not be elaborated here. The preset rolling pressure ratios of each stand in this embodiment are: φ1∶φ2∶φ3∶φ4∶φ5 = 1∶0.95∶0.8∶0.7∶0.6. The relevant calculation parameters of the adopted particle swarm algorithm are: the population size is 30, the maximum number of evolutionary generations is 50, the inertia weight is 0.5, the acceleration coefficient of the particle's optimal position is 2, the acceleration coefficient of the global optimal position is 2, and the curve of the fitness value changing with the number of evolutionary generations during the iterative calculation process is asFigure 6 as shown

[0164] The calculated reduction ratios and rolling pressures of each stand are shown in the 4th column and the 7th column of Table 5 respectively. Further calculated, the ratios of the rolling pressures of each stand under this reduction ratio distribution are: 24385∶23158∶19545∶16893∶14687≈1∶0.95∶0.802∶0.693∶0.602.

[0165] It can be seen that the ratios of the rolling pressures of each stand calculated in this embodiment are very close to the preset ratios, indicating that under the condition of this reduction ratio distribution, the rolling pressures of each stand are distributed according to the preset ratios. Since the plate crown of the rolled piece at the outlet of each stand is adapted to the rolling pressure of each stand, the plate crown of the rolled piece can be adjusted to the preset value under this rolling schedule, so as to achieve the purpose of accurately controlling the strip shape.

[0166] Table 5 Reduction ratio distribution and energy parameters of each stand calculated in Example 2

[0167]

[0168] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of the present disclosure. The appended method claims present the elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy recited.

[0169] In the above detailed description, various features are combined in a single embodiment to simplify the present disclosure. This method of disclosure should not be construed as reflecting an intention that the embodiments of the claimed subject matter require more features than are expressly recited in each claim. On the contrary, as reflected in the appended claims, this embodiment is in a state with fewer features than all the features of the disclosed single embodiment. Therefore, the appended claims are hereby expressly incorporated into the detailed description, where each claim stands alone as a separate preferred embodiment of this embodiment.

[0170] Those skilled in the art should also understand that all the illustrative logical blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments herein can be implemented as electronic hardware, computer software, or a combination thereof. To clearly illustrate the interchangeability between hardware and software, the above various illustrative components, blocks, modules, circuits, and steps have been generally described in terms of their functions. Whether such a function is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Skilled technicians can implement the described functions in a flexible manner for each specific application. However, such implementation decisions should not be construed as departing from the scope of protection of this disclosure.

[0171] The steps of the methods or algorithms described in conjunction with the embodiments herein can be directly embodied as hardware, software modules executed by a processor, or a combination thereof. The software modules can be located in a RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium well-known in the art. An exemplary storage medium is connected to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be an integral part of the processor. The processor and the storage medium can be located in an ASIC. The ASIC can be located in a user terminal. Of course, the processor and the storage medium can also exist as discrete components in the user terminal.

[0172] For software implementation, the technologies described in this application can be implemented using modules (e.g., procedures, functions, etc.) that execute the functions described in this application. These software codes can be stored in a memory unit and executed by a processor. The memory unit can be implemented within the processor or outside the processor. In the latter case, it is communicatively coupled to the processor via various means, which are well-known in the art.

[0173] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for the purpose of describing the above embodiments. However, those of ordinary skill in the art should recognize that the various embodiments can be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, this term is covered in a manner similar to the term "including" as interpreted when "including," is used as a transitional word in the claims. In addition, any term "or" used in the claims or the specification is intended to mean "non-exclusive or."

Claims

1. A method for obtaining the reduction ratio of a continuous rolling mill unit that can coordinate the rolling pressure of each stand, characterized in that, Including: S100. Input process parameters and continuous rolling mill equipment parameters; S200. Set the rolling pressure ratio of each stand to the first stand , and establish the coordinated optimization objectives and constraints for the rolling pressure of each stand; in S200, the objective function of the coordinated optimization objective for the rolling pressure of each stand is: , where is the rolling pressure of the first stand, with the unit , is the rolling pressure of the stand, with the unit , and the subscript represents the stand number, , is the number of stands; S300. Initially set the reduction ratio of the first stand to the stand using an optimization algorithm , , …, ; S400. Calculate the entrance thickness and exit thickness of the rolled piece for each stand; S500. Calculate the rolling force and energy parameters for each stand, where the rolling force and energy parameters for each stand include the rolling pressure, transmission torque, forward slip value, roll speed, and main motor power for each stand; In S500, the specific steps for calculating the rolling force and energy parameters for each stand are as follows: S501. Through repeated iteration of the stress differential equation and roll gap thickness equation in the roll gap deformation zone, calculate the unit pressure distribution, friction stress distribution, and roll gap thickness distribution in the roll gap deformation zone; The specific steps of S501 are as follows: S5011. Set the initial roll profile curve and determine the entrance position of the rolled piece; S5012. Calculate the unit pressure and friction stress for each section in the back slip zone from the entrance to the exit; S5013. Calculate the unit pressure and friction stress for each section in the forward slip zone from the exit to the entrance; S5014. Determine the unit pressure and friction stress for each section in the roll gap deformation zone; S5015. Calculate the roll gap thickness distribution from the unit pressure distribution; S5016. Determine whether the roll gap thickness distributions obtained from the previous and current calculations converge: If they converge, end the calculation; If they do not converge, go to step S5012 for the next round of iterative calculation until the roll gap thickness distribution converges; S502. Calculate the rolling pressure , unit , transmission torque , unit and the forward slip value , subscript represents the stand number, ; S503. Calculate the roll speed , unit and the main motor power , unit ; In S503, calculate the roll speed , unit and the main motor power , unit , the specific steps are as follows: S5031. At the maximum roll speed set for each stand Calculate the second flow rate value , and the calculation formula is: , where h is the thickness of the rolled piece at the outlet, with the unit of mm; S5032. Find the second flow rate value of each stand the minimum value of , and according to the second flow rate theorem, from calculate the roll speed of each stand , the calculation formula is: , is the thickness of the rolled piece at the outlet, unit is mm; S5033. Calculate the main motor power of each stand , and the main motor power and the ratio of the rated power of the main motor of this stand . The calculation formula is: , , , where is the transmission torque, is the roll body diameter of the work roll; S5034. Find out the maximum value of ; S5035. Judgment Is it greater than 1: If , then use to limit the roll speed of each stand. The limited roll speed is the calculated roll speed of each stand, that is ; When , then ; S5036. Calculate the main motor power of each rack , and the calculation formula is: ; S600. Determine whether the rolling pressure coordination optimization objectives and constraints for each stand are simultaneously satisfied: If not, adjust the reduction ratio values for each stand using an optimization algorithm, and then go to S400 for recalculation. If satisfied, end the calculation.

2. The method for obtaining the reduction ratio of a continuous rolling mill unit capable of coordinating the rolling pressures of each stand as claimed in claim 1, characterized in that, In S100, the process parameters include the incoming material thickness , unit , the finished product thickness , unit , the width of the rolled piece , unit , the number of stands and the deformation resistance data of the rolled piece. The equipment parameters of the continuous rolling mill include the working roll body diameter of each stand , unit , the working roll neck diameter , unit , the working roll body width , unit , the backup roll body diameter , unit , the backup roll neck diameter , unit and the backup roll body width , unit , where the subscript represents the stand number, .

3. The method for obtaining the reduction ratio of a continuous rolling mill unit capable of coordinating the rolling pressure of each stand, as described in claim 2, is characterized in that In the S400, calculate the entrance thickness of the rolled piece for each stand and the exit thickness of the rolled piece , specifically: when , , ; when , , ; when , , ; the subscript represents the stand number, , is the reduction ratio of the stand 4. The method for obtaining the reduction ratio of a continuous rolling mill unit capable of coordinating the rolling pressure of each stand according to claim 2, characterized in that, In S502, calculate the rolling pressure , unit , transmission torque , unit and the forward slip value , the specific calculation formula is: ； ； Wherein, is the number of discrete segments of the roll gap of the stand; is the length of the discrete segment of the roll gap of the stand, in mm; is the unit pressure of the th segment of the roll gap of the stand, in ; ; n is the number of segments into which the roll gap deformation zone is divided along the rolling direction; is the frictional stress of the th segment of the roll gap of the stand, in ; is the thickness difference between the th segment and the th segment of the roll gap of the stand, in ; ; and are respectively the thicknesses of the th segment and the th segment of the roll gap of the stand, in ; is the abscissa of the th segment of the roll gap of the stand, in ; is the rolling frictional force arm between the work roll and the backup roll, in ; wherein, is the elastic modulus of the work roll, in ; is the elastic modulus of the backup roll, in ; is the contact length between the work roll and the backup roll, in ; when , ; when , ; is the friction circle radius of the backup roll bearing, in ; wherein, is the rolling friction coefficient of the backup roll bearing; is the diameter of the backup roll neck, in ; is the thickness difference between the th segment + 1 and the r th segment of the roll gap of the r stand, in ; , is the roll gap thickness of the corresponding section of the neutral plane of the roll gap of the th stand. The corresponding section of the neutral plane of the roll gap of the th stand is the th section of the roll gap of the th stand, in the unit of , is the th section of the roll gap of the th stand, in the unit of .

5. A method for obtaining the reduction ratio of a continuous rolling mill unit that can coordinate the rolling pressure of each stand, characterized in that, In S300, the reduction ratios for each stand are initially set by the optimization algorithm and the reduction ratios for each stand are adjusted by the optimization algorithm. The optimization algorithm uses a genetic algorithm or a particle swarm algorithm.

6. The method for obtaining the reduction ratio of a continuous rolling mill unit capable of coordinating the rolling pressures of each stand according to claim 3, characterized in that, In the S600, it is judged whether the rolling pressure coordination optimization objectives and constraint conditions of each stand are simultaneously satisfied. The constraint conditions are specifically that all stands simultaneously satisfy the following inequalities: , where the subscript represents the stand number, , is the maximum reduction ratio of the stand, is the minimum reduction ratio of the stand, is the maximum roll speed of the stand, is the maximum rolling pressure of the stand, is the maximum transmission torque of the stand, is the rated power of the main motor of the stand.

Images