A method for dynamically setting bending roll force in a cold rolling threading process

Abstract

The present application belongs to the field of cold-rolled strip steel, and particularly relates to a method for dynamically setting bending roll force in a cold-rolled strip passing process, which comprises the number N of racks, upper and lower limits of the bending roll force of the i-th rack, dividing the strip passing process into n sections according to time, collecting the strip passing speed v of the i-th rack in the j-th section ij , dividing the bending roll force of each rack into m sections according to an adjustable area, collecting the shape value L calculated by a virtual shape meter on site ijk , calculating a shape evaluation function and a shape target function, setting an optimal bending roll force value S i0 , collecting the shape distribution value l calculated by the virtual shape meter on site ijk , calculating a shape evaluation function and a shape target function, setting an optimal bending roll force value S 0ij , establishing a function corresponding to the optimal bending roll force S 0ij and the strip passing speed v ij , and solving function coefficients a i1 , a i2 . The method for dynamically setting the bending roll force in the cold-rolled strip passing process can accurately control the dynamic setting of the bending roll force of the cold-rolled strip steel in the strip passing process, improve the strip passing shape, and reduce the rolling fluctuation caused by the shape defects.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of cold-rolled strip steel, and particularly relates to a method for dynamically setting a bending roll force in a cold-rolled strip threading process. BACKGROUND

[0002] In recent years, with the rapid development of the automobile, household appliance, instrument and food packaging industries, and the progress of modern plate processing industry in terms of high automation and the increasingly wide use of cold-rolled strip steel, users have put forward higher and higher requirements for the plate shape quality of cold-rolled strip steel. The threading process, as the beginning of the rolling process of the cold-rolling process, is of great significance to the entire rolling process. Since there is no front tension in the threading process and the unit is in a slow start state, production defects are prone to occur at this time, and in severe cases, production accidents can even occur. According to field statistics, defects generated in the threading process of the cold-rolling unit include deviation, slipping, mill vibration and even strip breakage, etc. However, the on-site operator often has no way to control the defects in the threading process. Therefore, for the cold-rolling unit, the development of the threading process control technology is extremely important for stable production on site.

[0003] As an important evaluation index in the threading process of the cold-rolling unit, the plate shape plays an important role in stable production and quality control of the strip steel. The quality of plate shape control is directly related to the treatment of production defects. In the threading process, equipment parameters and process characteristics often result in poor plate shape. For the plate shape control technology in the threading process, the particularity of the threading process, which is different from the normal rolling process, greatly increases the difficulty of technology development. According to research, the technical research on plate shape control in the threading process by experts in the cold-rolling industry mainly focuses on equipment operation, and lacks theoretical technical support and process guidance. Therefore, for the cold-rolling unit, the development of the plate shape control technology in the threading process has a breakthrough significance. As is known to all, bending roll is one of the important means for adjusting the plate shape of the strip steel, and is often used by on-site operators. In summary, the optimization of the plate shape in the threading process through the on-site basic control method, i.e. the control of the bending roll force, can lay a theoretical foundation for plate shape control and has important theoretical guiding significance for production personnel.

[0004] The present application aims to provide a method for dynamically setting a bending roll force in a cold-rolled strip threading process. The method can accurately control the cold-rolled strip in the threading process through the dynamic setting of the bending roll force, improve the threading plate shape, reduce the stable rolling fluctuations caused by plate shape defects, and lay a foundation for the normal operation of the cold-rolling unit. SUMMARY

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] (A) Collecting equipment parameters of the cold-rolling unit, including the number of racks N, the upper limit of the bending roll force of the i-th rack Simax , lower limit of bending roll force of stand i S imin .

[0007] (B) Divide the threading process into n segments according to time, and collect the threading speed v of the jth time segment of the i-th rack ij .

[0008] (C) Divide the bending roll force of each frame into m according to the adjustable area, and collect the kth bending roll force S calculated by the on-site virtual plate shape meter ik Under the action of ijk , where the bending roll force S ik :

[0009]

[0010] (D) Calculate the plate shape evaluation function G(X) under the action of the bending roller force of the i-th frame and the k-th frame 1ik The value of , where α is the weighting coefficient of the flatness evaluation function:

[0011]

[0012] (E) Calculate the plate shape objective function F(X) of the i-th rack 1i , and F(X) 1i Corresponding bending roll force setting value S i0 As the optimal bending roll force value of the i-th stand:

[0013] F(X) 1i =minG(X) 1ik (k=1,2,,,m)

[0014] (F) Collect the bending roll force S of the kth time period in the i-th frame and the j-th time period calculated by the on-site virtual shape meter ijk Plate shape distribution value l under the action ijk , and calculate the plate shape evaluation function G(X) 2ijk The value of q is the number of units into which the strip is divided in the transverse direction:

[0015]

[0016] (G) Calculate the plate shape objective function F(X) for the jth time period in the i-th rack 2ij , and F(X) 2ij Corresponding bending roll force setting value S 0ij As the optimal bending roll force value in the jth time period in the i-th stand:

[0017] F(X) 2ij =minG(X) 2ijk (k=1,2,,,m)

[0018] (H) the optimal bending force S in the i-th stand in (G) 0ij Based on the data corresponding to the time period, a function of the bending force and the threading speed in the i-th stand is established, and the coefficient value is solved by using the least square method, wherein a i0 is the optimal bending force value of the i-th stand, a i1 , a i2 are function coefficients, and the calculation is completed:

[0019] S i = a i0 + a i1 v + a i2 v 2

[0020] Compared with the prior art, the bending force dynamic setting method in the cold rolling threading process takes the plate shape control in the threading process as the target, realizes that the bending force in the threading process follows the change of the threading speed, and greatly improves the control effect of the plate shape of the threading steel in the cold rolling process. BRIEF DESCRIPTION OF DRAWINGS

[0021] The present application will be further described below in combination with the drawings and examples.

[0022] Figure 1 is a flow chart of the bending force dynamic setting method in the cold rolling threading process of the present application. DETAILED DESCRIPTION

[0023] Example 1:

[0024] The implementation steps are as follows:

[0025] (1) In step (A), the equipment parameters of the cold rolling mill are collected, including the number of stands N = 6, the upper limit of the bending force of the i = 1 ~ 6 stands S imax = 100t, and the lower limit of the bending force of the i = 1 ~ 6 stands S imin = -100t;

[0026] (2) In step (B), the threading process is divided into n = 5 periods according to time, and the threading speed v ij of the i = 1 ~ 6 stands in the j = 1 ~ 5 periods is collected, with the unit of m / min, as shown in Table 1;

[0027] Table 1 Threading speed v of 5 periods of 6 stands in Example 1 ij

[0028]

[0029] (3) In step (C), the bending roll force of each frame is divided into m = 11 according to the adjustable area, and the k = 1 to 11 bending roll forces S calculated by the on-site virtual plate shape meter are collected. ik Under the action of ijk , unit I, taking the first rack i=1 as an example: see Table 2;

[0030] Table 2 Plate shape values ​​of the first frame in the first embodiment under 11 bending roll forces in 5 time periods

[0031]

[0032] (4) In step (D), calculate the plate shape evaluation function G(X) under the action of the bending roll force of the i=1~6th frame and the k=1~11th frame. 1ik The value of α = 0.5 is the weighting coefficient of the plate shape evaluation function. After calculation, the plate shape evaluation function G(X) 1ik The values ​​of are shown in Table 3;

[0033]

[0034] Table 3 Plate shape evaluation function values ​​of the six stands under 11 bending roll forces in Example 1

[0035]

[0036]

[0037] (5) In step (E), calculate the plate shape objective function F(X) of the i-th rack 1i , and F(X) 1i Corresponding bending roll force setting value S i0 As the optimal bending roll force value of the i-th stand:

[0038] F(X) 1i =minG(X) 1ik (k=1,2,,,m)

[0039] After calculation, S i0 ={80,80,60,60,40,40}, unit t;

[0040] (6) In step (F), the bending roll force S of the i=1~6th frame and the j=1~5th time period calculated by the on-site virtual plate shape meter is collected. ijk Plate shape distribution value l under the action ijk , unit I, and calculate the plate shape evaluation function G(X) 2ijk The value of q is the number of units into which the strip is divided in the transverse direction:

[0041]

[0042] Take the first time period of the first stand as an example, the plate shape distribution value l ijk See Table 4, take the first stand as an example, the plate shape evaluation function value G(X) 2ijk See Table 5;

[0043] Table 4 Plate shape distribution values of the first time period of the first stand in Example 1 under the action of 11 bending roll forces

[0044]

[0045]

[0046] Table 5 Plate shape evaluation function values of the five time periods of the first stand in Example 1 under the action of 11 bending roll forces

[0047]

[0048] (7) In step (G), calculate the plate shape target function F(X) of the j = 1 ~ 5 time periods in the i = 1 ~ 6 stands 2ij , and F(X) 2ij The corresponding bending roll force setting value S 0ij is the optimal bending roll force value in the i = 1 ~ 6 stands:

[0049] F(X) 2ij = min G(X) 2ijk (k = 1, 2, …, m)

[0050] After calculation, the optimal bending roll force value S 0ij , unit t, see Table 6;

[0051] Table 6 Optimal bending roll force values S corresponding to the five time periods of the six stands in Example 1 0ij

[0052]

[0053] (8) In step (H), based on the data corresponding to the optimal bending roll force S 0ij of the i stand in (G) and the time period, establish a function of the bending roll force and the running speed in the i stand, and use the least square method to solve the coefficient value, where a i0 is the optimal bending roll force value of the i stand, a i1 , a i2 are function coefficients, and the calculation is completed:

[0054] S i = a i0 + ai1 v+a i2 v 2

[0055] The function coefficient of bending force and threading speed is calculated and shown in Table 7;

[0056] Table 7 Function coefficient of bending force and threading speed of 6 stands in Example 1

[0057]

[0058] In this example, the value of bending force in the threading process is dynamically set to optimize the shape control in the rolling process, and the shape qualified rate of the strip steel used in Example 1 is improved. The situation before and after the application is shown in Table 8.

[0059] Table 8 Shape qualified rate of strip steel used in Example 1 before and after application

[0060] Time 2021.01 2021.02 2021.03 2021.04 2021.05 2021.06 Before application 81.4％ 83.7％ 84.2％ 81.9％ 88.2％ 82.4％ Time 2021.07 2021.08 2021.09 2021.10 2021.11 2021.12 After application 92.5％ 91.6％ 94.5％ 96.8％ 96.2％ 97.3％

[0061] Example 2:

[0062] The implementation steps are as follows:

[0063] (1) In step (A), the equipment parameters of the cold rolling mill are collected, including the number of stands N = 5, the upper limit of bending force of the i = 1 ~ 5 stands S imax = 100t, the lower limit of bending force of the i = 1 ~ 5 stands S imin = -100t;

[0064] (2) In step (B), the threading process is divided into n = 5 segments according to time, and the threading speed v ij of the i = 1 ~ 5 stands in the j = 1 ~ 5 time segments is collected, with the unit of m / min, as shown in Table 9;

[0065] Table 9 Threading speed v of 5 time segments of 5 stands in Example 2 ij

[0066]

[0067] (3) In step (C), the bending force of each stand is divided into m = 11 according to the adjustable region, and the shape value L ijk of the i = 1 ~ 5 stands in the j = 1 ~ 5 time segments under the action of the k = 1 ~ 11 bending forces S ik is collected, with the unit of I, and the first stand i = 1 is taken as an example: see Table 10;

[0068] Table 10 Shape value of 5 time segments of the first stand in Example 2 under the action of 11 bending forces

[0069]

[0070] (4) In step (D), calculate the plate shape evaluation function G(X) under the action of the bending roll force of the i=1~5th frame and the k=1~11th frame. 1ik The value of , where a = 0.5 is the weighting coefficient of the plate shape evaluation function. After calculation, the plate shape evaluation function G (X) 1ik The values ​​of are shown in Table 11:

[0071]

[0072] Table 11 Plate shape evaluation function values ​​of the five frames under 11 bending roll forces in Example 2

[0073]

[0074] (5) In step (E), calculate the plate shape objective function F(X) of the i-th rack 1i , and F(X) 1i Corresponding bending roll force setting value S i0 As the optimal bending roll force value of the i-th stand:

[0075] F(X) 1i =minG(X) 1ik (k=1,2,,,m)

[0076] After calculation, S i0 ={80,80,60,40,40}, unit t;

[0077] (6) In step (F), the bending roll force S calculated by the virtual plate shape meter at the i=1~5th frame and the j=1~5th time period in the k=1~11th time period is collected. ijk Plate shape distribution value l under the action ijk , unit I, and calculate the plate shape evaluation function G(X) 2ijk The value of q is the number of units into which the strip is divided in the transverse direction:

[0078]

[0079] Taking the first time period of the first rack as an example, the plate shape distribution value l ijk See Table 12, taking the first rack as an example, the plate shape evaluation function value G(X) 2ijk See Table 13;

[0080] Table 12 Plate shape distribution values ​​under 11 bending roll forces in the first time period of the first frame in Example 2

[0081]

[0082] Table 13: Plate shape evaluation function value of 5 time periods in the first stand in Example 2 under the action of 11 bending forces

[0083]

[0084]

[0085] (7) In step (G), the plate shape target function F(X) of the j = 1 ~ 5 time periods in the i = 1 ~ 5 stands is calculated 2ij , and F(X) 2ij is obtained 0ij The corresponding bending force setting value S

[0086] F(X) 2ij = min G(X) 2ijk (k = 1, 2,..., m)

[0087] The calculated optimal bending force value S 0ij , unit t, see Table 14;

[0088] Table 14: Optimal bending force value S corresponding to 5 time periods in 5 stands in Example 2 0ij

[0089]

[0090] (8) In step (H), based on the data corresponding to the optimal bending force S 0ij in the i stand in (G) and the time period, the function of the bending force and the running speed in the i stand is established, and the coefficient value is solved using the least square method, where a i0 is the optimal bending force value of the i stand, a i1 , a i2 are function coefficients, and the calculation is completed:

[0091] S i = a i0 + a i1 v + a i2 v 2

[0092] The calculated function coefficients of the bending force and the running speed are shown in Table 15;

[0093] Table 15: Function coefficients of the bending force and the running speed in the 5 stands in Example 2

[0094]

[0095]

[0096] In this example, the value of the bending force in the threading process is dynamically set to optimize the shape control in the rolling process, and the shape qualification rate of the strip steel used in Example Two is improved. The situation before and after the application is shown in Table 16.

[0097] Table 16 Shape qualification rate of the strip steel used in Example Two before and after application

[0098] Time 2021.01 2021.02 2021.03 2021.04 2021.05 2021.06 Before application 82.1％ 82.7％ 85.2％ 84.1％ 82.5％ 86.8％ Time 2021.07 2021.08 2021.09 2021.10 2021.11 2021.12 After application Time Before application Time After application 91.2％ 94.6％ 93.1％ 97.3％ 97.8％ 98.2％

[0099] The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent control or modification made according to the spirit and essence of the main technical solution of the present application should be covered within the protection scope of the present application.

Claims

1. A method for dynamically setting the bending roll force during cold rolling strip threading, characterized in that: (A) Collect equipment parameters of the cold rolling mill, including the number of stands N, the upper limit of the bending roll force of the i-th stand S imax , lower limit of bending roll force of stand i S imin ; (B) Divide the threading process into n segments according to time, and collect the threading speed v of the jth time segment of the i-th rack ij ; (C) Divide the bending roll force of each frame into m according to the adjustable area, and collect the kth bending roll force S calculated by the on-site virtual plate shape meter ik Under the action of ijk , where the bending roll force S ik : (D) Calculate the plate shape evaluation function G(X) under the action of the bending roller force of the i-th frame and the k-th frame 1ik The value of , where α is the weighting coefficient of the flatness evaluation function: (E) Calculate the plate shape objective function F(X) of the i-th rack 1i , and F(X) 1i Corresponding bending roll force setting value S i0 As the optimal bending roll force value of the i-th stand: F(X) 1i =min G(X) 1ik (k=1,2,,,m) (F) Collect the bending roll force S of the kth time period in the i-th frame and the j-th time period calculated by the on-site virtual shape meter ijk Plate shape distribution value l under the action ijk , and calculate the plate shape evaluation function G(X) 2ijk The value of q is the number of units into which the strip is divided in the transverse direction: (G) Calculate the plate shape objective function F(X) for the jth time period in the i-th rack 2ij , and F(X) 2ij Corresponding bending roll force setting value S 0ij As the optimal bending roll force value in the jth time period in the i-th stand: F(X) 2ij =min G(X) 2ijk (k=1,2,,,m) (H) Take the optimal bending roll force S in the i-th frame in (G) 0ij Based on the data corresponding to each time period, the function of the bending roller force and the belt threading speed in the i-th frame is established, and the coefficient value is solved using the least squares method, where a i0 is the optimal bending roll force value of the i-th stand, a i1 、a i2 is the function coefficient, and the calculation ends: With i =a i0 +a i1 in+and i2 in 2 。

Images