A method for optimizing the working pass mode of a 5+1 cold rolling mill frame

Abstract

The present invention discloses a method for optimizing the working pass mode of a 5+1 type cold rolling mill frame, and the method comprises the following steps: (a) collecting basic equipment parameters of a six-frame cold rolling mill; (b) collecting incoming material parameters; (c) defining pass selection process parameters; (d) judging the six-pass production mode; (e) judging the five-pass production mode; (f) judging the four-pass production mode. The method of the present invention realizes the optimization of the comprehensive rolling capacity utilization of the unit, which not only ensures the rolling stability and finished product quality of the unit during the cold rolling process, but also ensures the most reasonable economic cost, thereby achieving the purpose of producing various types of steel. Compared with the prior art, the optimization method of this case has achieved significant application effects on site, which not only ensures the stable state of the rolling process, but also greatly reduces the production cost due to the reduction of frames, thereby realizing the optimal utilization of the unit's rolling capacity and bringing economic benefits to the enterprise.

Description

Technical Field

[0001] This patent relates to the field of cold rolling, and in particular to an optimization method for optimizing the working pass mode of a 5+1 type cold rolling mill frame. Background Art

[0002] In the future, there will be more and more types of steel, and the amount of steel used will also increase. In order to meet the needs of production and development, a domestic factory built a new six-stand cold rolling unit, of which five stands were relocated from the original 1750 acid rolling unit, and another small roller diameter stand was added. Considering the degree of work hardening of each pass of strip steel, the production efficiency of the unit, and the motor power, the newly added small roller diameter stand is the fourth stand. The six-stand cold rolling unit composed of five conventional six-roll mills and one small roller diameter six-roll mill is the first application both at home and abroad.

[0003] In the actual production process of the 5+1 type cold rolling mill, the incoming material thickness of each steel grade is different, and the final required thickness is also different. If the six racks are operated simultaneously during the production of each type of steel, the economic cost will be higher. The 5+1 type cold rolling mill currently has three production modes: four passes, five passes, and six passes. For different types of steel, in actual production, in order to ensure stable production of the unit and minimize production energy consumption, which production mode should the 5+1 type cold rolling mill choose? And in the five passes, which rack should be shut down, and in the four passes, which two racks should be shut down? This problem needs to be solved urgently. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art. Starting from the aspect of rolling stability, a theoretical analysis is carried out. First, the frames working under different passes are selected, and then the rolling stability of each frame under different passes is compared to select the most suitable production pass, so as to achieve the optimal frame mode of the 5+1 type cold rolling mill.

[0005] For this purpose, the technical solution adopted in the present invention is:

[0006] A method for optimizing a working pass mode of a 5+1 type cold rolling mill frame, wherein the 5+1 type cold rolling mill frame includes 5 conventional rolling mills and a 4th frame small roller diameter rolling mill, and the working pass mode optimization method includes the following steps:

[0007] (a) Collection of basic equipment parameters of six-stand cold rolling mill;

[0008] (b) Collection of incoming material parameters;

[0009] (c) Pass selection process parameter definition;

[0010] (d) Six-pass production mode judgment: Calculate the rolling stability in this mode and judge Is it established? If yes, then go to step (e) to determine the five-pass production mode. If not, then output the six-pass production mode.

[0011] in, , are the six-pass rolling stability margin and the critical value of rolling stability margin, is the six-pass mode rolling stability guarantee coefficient;

[0012] (e) Judgment of the five-pass production mode: In the five-pass production mode, one of the stands F3 and F4 is selected to be disabled; when the F4 stand is disabled, the first five-stand combination is used: F1, F2, F3, F5, F6; when the F3 stand is disabled, the second five-stand combination is used: F1, F2, F4, F5, F6; in terms of rolling stability, the first combination is more stable than the second combination, but the second combination has better control over the plate shape; the rolling stability under the two five-stand combinations is calculated respectively to determine , If only one of the two conditions is met, output this five-rack combination five-pass production mode; if neither is met, output the six-pass production mode; if both conditions are met, judge Is it established? If so, proceed to step (f) to determine the four-pass production mode. If not, output the first five-frame combination five-pass production mode.

[0013] in, , They are the five-pass rolling stability margins of the first and second five-stand combinations, respectively; , They are the critical values ​​of stable margin of five-pass rolling for the first and second five-stand combinations, respectively; is the five-pass mode rolling stability guarantee coefficient;

[0014] (f) Judgment of four-pass production mode: The four-pass production mode includes the first four-stand combination: F1, F2, F5, F6; and the second four-stand combination F1, F4, F5, F6; the stability of the first combination is greater than the second, and the first combination has better control over the plate shape than the second combination; the rolling stability under the two four-stand combinations is calculated and judged respectively. , If only one of the two conditions is met, output this four-rack combination four-pass production mode; if neither is met, output the first five-rack combination five-pass production mode, which has better stability; if both conditions are met, output the first four-rack combination four-pass production mode;

[0015] in, , They are the four-pass rolling stability margins of the first and second four-stand combinations respectively;

[0016] , They are the critical values ​​of stable margin of four-pass rolling for the first and second four-stand combinations respectively.

[0017] Furthermore, the basic equipment parameters of the six-stand cold rolling mill group in step (a) are collected, including: the working roll diameters of the conventional rolling mill and the small roll diameter rolling mill of the fourth stand; , the maximum allowable rolling force , the maximum allowable rolling power , No. Maximum rack outlet tension With minimum ;

[0018] The step (b) of collecting incoming material parameters includes: the thickness of the incoming strip steel , finished strip steel thickness required , strip width , Strip strength , critical value of slip injury index , critical value of slip factor ;

[0019] The step (c) of defining the parameters of the pass selection process includes: setting the rolling force of each stand to The rolling power is , slip factor , Slip injury index , the outlet tension is The rolling speed is , Six-pass reduction rate , the six-pass pressing distribution is: , the five-pass reduction rates are: , The five-pass pressing distribution is as follows: , , the four-pass reduction rates are: , , the four-pass pressing distribution is: , ; The optimization objective functions of the six-pass, five-pass, and four-pass tension systems are: , , ; The optimization results of the six-pass exit tension system are: The optimization results of the five-pass exit tension system are: , The optimization results of the four-pass outlet tension system are , ;

[0020] The step (d) specifically comprises the following steps:

[0021] (d1) Given the six-pass mode, the reduction rate of each pass is: ;

[0022] (d2) Calculate the pressure distribution of each pass in the six-pass mode, that is: , , , , , ;

[0023] (d3) Setting the initial parameters of the tension system optimization process , given the optimization step size , ;

[0024] (d4) Set the initial value of the objective function ;

[0025] (d5) Order ;

[0026] (d6) Order ;

[0027] (d7) Order ;

[0028] (d8) Judgment Is it established? If established, then , go to step (d6); if not, go to step (d9);

[0029] (d9) Calculate the rolling pressure of each stand , rolling power , slip factor , Slip injury index ;

[0030] (d10) Judgment , , Is it true? If so, go to step (d11); if not, go to step (d13);

[0031] (d11) Calculate the optimization objective function of the tension system of the incoming material cold rolling process

[0032] ,

[0033] To optimize the tension system process, the influence coefficient of the material slippage control margin is calculated. To optimize the tension system process, the influence coefficient of the thermal slip control margin of incoming materials is The coefficient of rolling stability of small-diameter rolling mill in the process of tension system optimization is The coefficient of influence of rolling stability of conventional rolling mill in the process of tension system optimization;

[0034] (d12) Determine inequalities Is it established? If established, then let , go to step (d13); if not, go directly to step (d13);

[0035] (d13) Order ;

[0036] (d14) Determine inequalities Is it established? If established, then let , go to step (d7); if not, let , go to step (d15);

[0037] (d15) Determine inequality Is it established? If established, then let , go to step (d14); if not, go to step (d16);

[0038] (d16) Obtain the optimal outlet tension system result corresponding to the maximum value of the objective function

[0039] ,in ;

[0040] (d17) Calculate the six-pass rolling stability margin and the critical value of rolling stability margin: , ,

[0041] ,

[0042] Six-pass strip slip factor stability coefficient, Stability coefficient of the six-pass strip slip index;

[0043] (d18) Judgment Is it established? If yes, then go to step (e) to determine the five-pass production mode. If not, then output the six-pass production mode.

[0044] The step (e) specifically comprises the following steps:

[0045] (e1) Given two five-pass combination modes, the reduction rates of each pass are: , ;

[0046] (e2) Calculate the pressure distribution of each pass in two five-pass combination modes. The first combination: , , , , ;

[0047] The second combination: , , , , ;

[0048] (e3) Use the calculation method in steps d3-d16 to calculate the tension system of the two combinations respectively , ;

[0049] (e4) Calculation of rolling stability margin under the first five-stand combination of the five-pass mode , critical value of rolling stability margin ,

[0050] ,

[0051] ,

[0052] Stability coefficient of five-pass strip slip factor, Stability coefficient of five-pass strip slip index;

[0053] (e5) Calculation of rolling stability margin under the second five-stand combination of the five-pass mode , critical value of rolling stability margin ,

[0054] ,

[0055] ,

[0056] Stability coefficient of five-pass strip slip factor, Stability coefficient of five-pass strip slip index;

[0057] (e6) Judgment , If only one of the two conditions is met, output this five-rack combination five-pass production mode; if neither is met, output the six-pass production mode; if both conditions are met, judge Is it established? If so, proceed to step (f) to determine the four-pass production mode. If not, output the first five-frame combination five-pass production mode.

[0058] The step (f) specifically comprises the following steps:

[0059] (f1) Given two four-pass combination modes, the reduction rates of each pass are: , ;

[0060] (f2) Calculate the pressure distribution of each pass in the two four-pass combination modes,

[0061] The first combination: , , , ;

[0062] The second combination: , , , ;

[0063] (f3) Use the calculation method in steps d3-d16 to calculate the tension system of the two combinations respectively , ;

[0064] (f4) Calculate the rolling stability margin under the first four-stand combination of the four-pass mode , critical value of rolling stability margin ,

[0065] ,

[0066] ,

[0067] The stability coefficient of the strip slip factor in the four passes, Stability coefficient of the four-pass strip slip index;

[0068] (f5) Calculate the rolling stability margin under the second four-stand combination of the four-pass mode , critical value of rolling stability margin ,

[0069] ,

[0070] ;

[0071] (f6) Judgment , If only one of the two conditions is met, output this four-rack combination four-pass production mode; if neither is met, output the first five-rack combination five-pass production mode; if both conditions are met, output the first four-rack combination four-pass production mode.

[0072] The beneficial effects of the present invention are as follows: the 5+1 type cold rolling unit frame working pass mode optimization method of the present invention realizes the optimization of the comprehensive rolling capacity utilization of the unit, which not only ensures the rolling stability and finished product quality of the unit during the cold rolling process, but also ensures the most reasonable economic cost, thereby achieving the purpose of producing various types of steel. Compared with the prior art, the optimization method of this case has achieved significant application effects on site, which not only ensures the stable state of the rolling process, but also greatly reduces the production cost due to the reduction of the frames, realizes the optimization of the rolling capacity of the unit, and brings economic benefits to the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 is a flow chart of the optimization method of the present invention;

[0074] Figure 2 It is a six-pass production mode judgment flow chart of the present invention;

[0075] Figure 3 It is a five-pass production mode judgment flow chart of the present invention;

[0076] Figure 4 It is a four-pass production mode judgment flow chart of the present invention. DETAILED DESCRIPTION

[0077] The present invention is further described in detail below in conjunction with two embodiments, a method for optimizing the working pass mode of a 5+1 type cold rolling mill frame, wherein the 5+1 type cold rolling mill frame includes 5 conventional rolling mills and a 4th frame small roller diameter rolling mill. Figure 1 As shown, the working pass mode optimization method includes the following steps:

[0078] (a) Collection of basic equipment parameters of six-stand cold rolling mill;

[0079] (b) Collection of incoming material parameters;

[0080] (c) Pass selection process parameter definition;

[0081] (d) Six-pass production mode judgment: Calculate the rolling stability in this mode and judge Is it established? If yes, then go to step (e) to determine the five-pass production mode. If not, then output the six-pass production mode.

[0082] (e) Judgment of the five-pass production mode: In the five-pass production mode, one of the stands F3 and F4 is selected to be disabled; when the F4 stand is disabled, the first five-stand combination is F1, F2, F3, F5, F6; when the F3 stand is disabled, the second five-stand combination is F1, F2, F4, F5, F6; the rolling stability under the two five-stand combinations is calculated and judged respectively. , If only one of the two conditions is met, output this five-rack combination five-pass production mode; if neither is met, output the six-pass production mode; if both conditions are met, judge Is it established? If so, proceed to step (f) to determine the four-pass production mode. If not, output the first five-frame combination five-pass production mode.

[0083] (f) Determination of four-pass production mode: The four-pass production mode includes the first four-stand combination: F1, F2, F5, F6; and the second four-stand combination F1, F4, F5, F6. The rolling stability under these two four-stand combinations is calculated and determined. , If only one of the two conditions is met, output this four-rack combination four-pass production mode; if neither is met, output the first five-rack combination five-pass production mode; if both conditions are met, output the first four-rack combination four-pass production mode.

[0084] The specific parameters and optimization calculation process and steps of the two embodiments are as follows: Example 1

[0085] First, in step (a), the basic equipment parameters of the 5+1 type cold rolling mill group are collected, including: the working roll diameters of the conventional rolling mill (1st, 2nd, 3rd, 5th, and 6th stands) and the small roll diameter rolling mill (4th stand) are shown in Table 1, and the maximum rolling pressure allowable value is

[0086] , the maximum allowable rolling power , No. Maximum rack outlet tension With minimum ;

[0087] Working roll parameters of each stand:

[0088] parameter F1 F2 F3 F4 F5 F6 Working roll diameter (mm) 455 455 455 360 455 455 Working roll length (mm) 1780 1780 1780 1780 1780 1780

[0089] In step (b), the incoming material parameters are collected, including: collecting the incoming strip thickness , finished strip steel thickness required , strip width , incoming material yield strength , critical value of slip factor of each rack , critical value of slip injury index ;

[0090] In step (c), the parameters of the pass selection process are defined, including: setting the rolling force of each stand to The rolling power is , slip factor , Slip injury index , the outlet tension is The rolling speed is , Six-pass reduction rate , the six-pass pressing distribution is: The five-pass reduction rates are , The five-pass pressing distribution is as follows: , The four-pass reduction rates are , , the four-pass pressing distribution is: , ; The optimization objective functions of the six-pass, five-pass, and four-pass tension systems are: , , ; The optimization results of the six-pass exit tension system are: The optimization results of the five-pass exit tension system are: , The optimization results of the four-pass outlet tension system are , ; The six-pass rolling stability margin and the critical value of rolling stability margin are: , ; The five-pass rolling stability margins are: , , the critical values ​​of stable margins of five-pass rolling are: , ; The stable margins of the four rolling passes are: , ; The critical values ​​of stable margins of the four-pass rolling are , ;

[0091] (d) Make six-pass production mode judgment, such as Figure 2 As shown, the specific steps include:

[0092] In step (d1), the reduction rate of each pass in the given six-pass mode is: ;

[0093] In step (d2), the pressure distribution of each pass in the six-pass mode is calculated as:

[0094]

[0095] In step (d3), set the initial parameters of the tension system optimization process , Given the optimization step size ;

[0096] In step (d4), the initial values ​​of the six-pass objective function are set. , critical value of six-pass substability comprehensive margin ;

[0097] In step (d5), ;

[0098] In step (d6), ;

[0099] In step (d7) ;

[0100] In step (d8), determine ; established, then , go to step (d6) and output

[0101] ;

[0102] In step (d9), the rolling pressure of each stand is calculated. , rolling power , calculate the slip factor , Slip injury index ,

[0103] ,

[0104] ,

[0105] ,

[0106] ;

[0107] In step (d10) , , Established, go to step (d11);

[0108] In step (d11), the optimization objective function of the tension system of the incoming material cold rolling process is calculated.

[0109] Where: , , ;

[0110] In step (d12) the inequality Established; established, then , go to step (d13);

[0111] In step (d13) ;

[0112] In step (d14) the inequality Established; then , go to step (d7) and start the cycle;

[0113] In step (d15) when the inequality Not true, end the loop and go directly to step (d16);

[0114] In step (d16), the optimal outlet tension system result corresponding to the maximum value of the objective function is obtained.

[0115] ,in ;

[0116] In step (d17), the six-pass rolling stability margin and the critical value of the rolling stability margin are calculated: , ,

[0117] ,

[0118] ,

[0119] ;

[0120] In step (d18), determine Established among them, , then go to step (e).

[0121] In step (e), five-pass production mode determination is performed, such as Figure 3 As shown, the specific steps include:

[0122] In step (e1), the reduction rates of each pass in two five-pass combination modes are given as follows:

[0123] ; ;

[0124] In step (e2), the press distribution of the two combinations of five passes is calculated:

[0125] ,

[0126] ;

[0127] In step (e3) the tension regimes for the two combinations of five passes are calculated:

[0128] ,

[0129] ;

[0130] In step (e4), the rolling stability margin under the first five-stand combination of the five-pass mode is calculated. , critical value of rolling stability margin ,

[0131] ,

[0132] ,

[0133] ;

[0134] In step (e5), the rolling stability margin under the second five-stand combination of the five-pass mode is calculated. , critical value of rolling stability margin ,

[0135] ,

[0136] ,

[0137] ;

[0138] In step (e6) , Both conditions are met, and Establishment , where , then proceed to step (f).

[0139] In step (f), four-pass production mode determination is performed, such as Figure 4 As shown, the specific steps include:

[0140] In step (f1), the reduction rates of each pass in two four-pass combination modes are given, which are:

[0141] ; ;

[0142] In step (f2), the press distribution of the two combinations of four passes is calculated:

[0143] ,

[0144] ;

[0145] 3) Calculate the tension system of two combinations of four passes:

[0146] ,

[0147] ;

[0148] In step (f4), the rolling stability margin under the first four-stand combination of the four-pass mode is calculated. , critical value of rolling stability margin ,

[0149] ,

[0150] ,

[0151] ;

[0152] In step (f5), the rolling stability margin under the second four-stand combination of the four-pass mode is calculated. , critical value of rolling stability margin ,

[0153] ,

[0154] ,

[0155] ;

[0156] In step (f6) , If both conditions are met, the first four-rack combination four-pass production mode is output.

[0157] First, in step (a), the basic equipment parameters of the 5+1 type cold rolling mill group are collected, including: the working roll diameters of the conventional rolling mill (1st, 2nd, 3rd, 5th, and 6th stands) and the small roll diameter rolling mill (4th stand) are shown in Table 1, and the maximum rolling pressure allowable value is , the maximum allowable rolling power , No. Maximum rack outlet tension With minimum ;

[0158] ;

[0159] Working roll parameters of each stand:

[0160] parameter F1 F2 F3 F4 F5 F6 Working roll diameter (mm) 455 455 455 360 455 455 Working roll length (mm) 1780 1780 1780 1780 1780 1780 ;

[0161] In step (b), the incoming material parameters are collected, including: collecting the incoming strip thickness , finished strip steel thickness required , strip width , incoming material yield strength , critical value of slip factor of each rack , critical value of slip injury index ;

[0162] In step (c), the parameters of the pass selection process are defined, which is the same as in Example 1;

[0163] In step (d), the six-pass production mode is determined, such as Figure 1 As shown, the specific steps include:

[0164] In step (d1), the reduction rate of each pass in the given six-pass mode is: ;

[0165] In step (d2), the pressing distribution in the six-pass mode is calculated;

[0166] ;

[0167] In step (d3), set the initial parameters of the tension system optimization process , Given the optimization step size ;

[0168] In step (d4), the initial values ​​of the six-pass objective function are set. , critical value of six-pass substability comprehensive margin ;

[0169] In step (d5), ;

[0170] In step (d6), ;

[0171] In step (d7) ;

[0172] In step (d8), determine ; established, then , go to step (d6) and output ;

[0173] In step (d9), the rolling pressure of each stand is calculated. , rolling power , calculate the slip factor , Slip injury index ,

[0174] ,

[0175] ,

[0176] ,

[0177] ;

[0178] In step (d10) , , Established, go to step (d11);

[0179] In step (d11), the optimization objective function of the tension system of the incoming material cold rolling process is calculated;

[0180] ,

[0181] Where: , , ;

[0182] In step (d12) the inequality Established; established, then , go to step (d13);

[0183] In step (d13) ; In step (d14) the inequality Established; then , go to step (d8) and start the cycle;

[0184] In step (d15) when the inequality Not true, end the loop and go directly to step (d16);

[0185] In step (d16), the optimal outlet tension system result corresponding to the maximum value of the objective function is obtained:

[0186] ,in ;

[0187] Then in step (d17), the six-pass rolling stability margin and the critical value of the rolling stability margin are calculated: , ,

[0188] ,

[0189] ;

[0190] In step (d18) Established, of which , proceed to step (e).

[0191] In step (e), five-pass production mode determination is performed, such as Figure 2 As shown, the specific steps include:

[0192] In step (e1), the reduction rates of each pass in two five-pass combination modes are given as follows:

[0193] ; ;

[0194] In step (e2), the press distribution of the two combinations of five passes is calculated:

[0195] ,

[0196] ;

[0197] In step (e3) the tension regimes for the two combinations of five passes are calculated:

[0198] ,

[0199] ;

[0200] In step (e4), the rolling stability margin under the first five-stand combination of the five-pass mode is calculated. , critical value of rolling stability margin ,

[0201] ,

[0202] ,

[0203] ;

[0204] In step (e5), the rolling stability margin under the second five-stand combination of the five-pass mode is calculated. , critical value of rolling stability margin ,

[0205] ,

[0206] ,

[0207] ;

[0208] In step (e6), determine , Both conditions are met, but Not established, among which , then the first five-rack combination five-pass mode is output.

[0209] The above contents are only used to illustrate the technical solution of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention made by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for optimizing a working pass mode of a 5+1 type cold rolling mill frame, wherein the 5+1 type cold rolling mill frame comprises 5 conventional rolling mills and a 4th frame small roller diameter rolling mill, Features: The working pass mode optimization method comprises the following steps: (a) Collection of basic equipment parameters of six-stand cold rolling mill; (b) Collection of incoming material parameters; (c) Pass selection process parameter definition; (d) Six-pass production mode judgment: Calculate the rolling stability in this mode and judge Is it established? If yes, then go to step (e) to determine the five-pass production mode. If not, then output the six-pass production mode. in, , are the six-pass rolling stability margin and the critical value of rolling stability margin, is the six-pass mode rolling stability guarantee coefficient; (e) Judgment of the five-pass production mode: In the five-pass production mode, one of the stands F3 and F4 is selected to be disabled; when the F4 stand is disabled, the first five-stand combination is F1, F2, F3, F5, F6; when the F3 stand is disabled, the second five-stand combination is F1, F2, F4, F5, F6; the rolling stability under the two five-stand combinations is calculated and judged respectively. , If only one of the two conditions is met, output this five-rack combination five-pass production mode; if neither is met, output the six-pass production mode; if both conditions are met, judge Is it established? If so, proceed to step (f) to determine the four-pass production mode. If not, output the first five-frame combination five-pass production mode. in, , They are the five-pass rolling stability margins of the first and second five-stand combinations, respectively; , They are the critical values ​​of stable margin of five-pass rolling for the first and second five-stand combinations, respectively; is the five-pass mode rolling stability guarantee coefficient; (f) Determination of four-pass production mode: The four-pass production mode includes the first four-stand combination: F1, F2, F5, F6; and the second four-stand combination F1, F4, F5, F6. The rolling stability under these two four-stand combinations is calculated and determined. , If only one of the two conditions is met, output this four-rack combination four-pass production mode; if neither is met, output the first five-rack combination five-pass production mode; if both conditions are met, output the first four-rack combination four-pass production mode; in, , They are the four-pass rolling stability margins of the first and second four-stand combinations respectively; , They are the critical values ​​of stable margin of four-pass rolling for the first and second four-stand combinations respectively.

2. According to claim 1, the 5+1 type cold rolling mill frame working pass mode optimization method, Features: The step (a) of collecting basic equipment parameters of the six-stand cold rolling mill group includes: the working roll diameter of the conventional rolling mill and the small roll diameter rolling mill of the fourth stand; , the maximum allowable rolling force , the maximum allowable rolling power , No. Maximum rack outlet tension With minimum ; The step (b) of collecting incoming material parameters includes: the thickness of the incoming strip steel , finished strip steel thickness required , strip width , Strip strength , critical value of slip injury index , critical value of slip factor ; The step (c) of defining the parameters of the pass selection process includes: setting the rolling force of each stand to The rolling power is , slip factor , Slip injury index , the outlet tension is The rolling speed is , Six-pass reduction rate , the six-pass pressing distribution is: , the five-pass reduction rates are: , The five-pass pressing distribution is as follows: , , the four-pass reduction rates are: , , the four-pass pressing distribution is: , ; The optimization objective functions of the six-pass, five-pass, and four-pass tension systems are: , , ; The optimization results of the six-pass exit tension system are: The optimization results of the five-pass exit tension system are: , The optimization results of the four-pass outlet tension system are , ; The step (d) specifically comprises the following steps: (d1) Given the six-pass mode, the reduction rate of each pass is: ; (d2) Calculate the pressure distribution of each pass in the six-pass mode, that is: , , , , , ; (d3) Setting the initial parameters of the tension system optimization process , given the optimization step size , ; (d4) Set the initial value of the objective function ; (d5) Order ; (d6) Order ; (d7) Order ; (d8) Judgment Is it established? If established, then , go to step (d6); if not, go to step (d9); (d9) Calculate the rolling pressure of each stand , rolling power , slip factor , Slip injury index ; (d10) Judgment , , Is it true? If so, go to step (d11); if not, go to step (d13); (d11) Calculate the optimization objective function of the tension system of the incoming material cold rolling process To optimize the tension system process, the influence coefficient of the material slippage control margin is calculated. To optimize the tension system process, the influence coefficient of the thermal slip control margin of incoming materials is The coefficient of rolling stability of small-diameter rolling mill in the process of tension system optimization is The coefficient of influence of rolling stability of conventional rolling mill in the process of tension system optimization; (d12) Determine inequalities Is it established? If established, then let , go to step (d13); if not, go directly to step (d13); (d13) Order ; (d14) Determine inequalities Is it established? If established, then let , go to step (d7); if not, let , go to step (d15); (d15) Determine inequality Is it established? If established, then let , go to step (d14); if not, go to step (d16); (d16) Obtain the optimal outlet tension system result corresponding to the maximum value of the objective function ,in ; (d17) Calculate the six-pass rolling stability margin and the critical value of rolling stability margin: , , 、 ， Six-pass strip slip factor stability coefficient, Stability coefficient of the six-pass strip slip index; (d18) Judgment Is it established? If yes, then go to step (e) to determine the five-pass production mode. If not, then output the six-pass production mode. The step (e) specifically comprises the following steps: (e1) Given two five-pass combination modes, the reduction rates of each pass are: , ; (e2) Calculate the pressure distribution of each pass in two five-pass combination modes. The first combination: , , , , ; The second combination: , , , , ; (e3) Use the calculation method in steps d3-d16 to calculate the tension system of the two combinations respectively , ; (e4) Calculation of rolling stability margin under the first five-stand combination of the five-pass mode , critical value of rolling stability margin ， ， Stability coefficient of five-pass strip slip factor, Stability coefficient of five-pass strip slip index; (e5) Calculation of rolling stability margin under the second five-stand combination of the five-pass mode , critical value of rolling stability margin , ， ， Stability coefficient of five-pass strip slip factor, Stability coefficient of five-pass strip slip index; (e6) Judgment , If only one of the two conditions is met, output this five-rack combination five-pass production mode; if neither is met, output the six-pass production mode; if both conditions are met, judge Is it established? If so, proceed to step (f) to determine the four-pass production mode. If not, output the first five-frame combination five-pass production mode. The step (f) specifically comprises the following steps: (f1) Given two four-pass combination modes, the reduction rates of each pass are: , ; (f2) Calculate the pressure distribution of each pass in the two four-pass combination modes, The first combination: , , , ; The second combination: , , , ; (f3) Use the calculation method in steps d3-d16 to calculate the tension system of the two combinations respectively , ; (f4) Calculate the rolling stability margin under the first four-stand combination of the four-pass mode , critical value of rolling stability margin , ， ， The stability coefficient of the strip slip factor in the four passes, Stability coefficient of the four-pass strip slip index; (f5) Calculate the rolling stability margin under the second four-stand combination of the four-pass mode , critical value of rolling stability margin , ， ， (f6) Judgment , If only one of the two conditions is met, output this four-rack combination four-pass production mode; if neither is met, output the first five-rack combination five-pass production mode; if both conditions are met, output the first four-rack combination four-pass production mode.

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