Twenty-high roll mill asymmetric strip shape forecasting method based on reverse iteration method

Abstract

The invention provides a twenty-high roll mill asymmetric strip shape forecasting method based on a reverse iteration method, and belongs to the technical field of metallurgical rolling. The method comprises the following steps: collecting equipment parameters of a twenty-high rolling mill, characteristic parameters of typical rolled strips and corresponding rolling process parameters; dividing units and solving influence coefficients; forecasting the transverse distribution value of the pre-tensile stress of the strip during rolling; and strip outlet plate shape transverse distribution during rolling is forecasted. A roll system elastic deformation model is used for deducing a formula related to rolling pressure distribution, and meanwhile, a plastic deformation model is used for calculating strip outlet thickness transverse distribution. Although a large relaxation factor is used for iterative calculation, the calculation stability can still be ensured, and the overall calculation speed is increased. Two calculation examples show that the calculation result of the asymmetric strip shape forecasting method for the twenty-high rolling mill based on the reverse iteration method is well matched with that of a traditional method, and the calculation speed is increased by about three times.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgical rolling, and in particular to a method for predicting the asymmetric plate shape of a twenty-high rolling mill based on a reverse iteration method. Background Art

[0002] As the steel industry transforms towards green and intelligent manufacturing, its production efficiency and product quality are steadily improving. Among them, high-strength thin strips have excellent comprehensive performance and are increasingly becoming key materials in high-end manufacturing fields such as aerospace, marine, and new energy. High-strength thin strips have high yield strength and work hardening during the cold rolling process. The working rolls of traditional four- and six-roll mills have large diameters and poor thinning capabilities, and their ability to produce high-strength thin strips is insufficient. Twenty-roll mills are [1-2] It is one of the core equipment for producing high-strength thin strips. The flatness prediction model is the basis of various flatness control technologies. [3-5] .

[0003] References:

[0004] [1] Cao Wenchang, Chen Qingsong, Luo Xiaopeng. Twenty-high rolling mill: China, CN201220614749.1[P]. 2012-11-19.

[0005] [2] Zhou Guanyu, He Anrui, Liu Chao, et al. Study on deformation behavior of wide industrial pure titanium strip rolled by 20-roll mill [J]. Rare Metal Materials and Engineering, 2020, 49(7): 2333-2339;

[0006] [3] Sun Jianliang, Yan Mingze, Li Mingyuan, et al. Analysis of deformation and plate shape control of support roll group of 20-high rolling mill [J]. Steel, 2021, 56(12): 85-95.

[0007] [4] Zhang Qingdong, Dai Chang, Wen Jie, et al. Simulation study on plate shape control performance of 20-high Sendzimir mill [J]. Steel Rolling, 2013, 30(3): 1-6.

[0008] [5] Wang Hui, Qin Xiaofeng, Xu Kun. Optimization method of rolling process parameters of Sendzimir twenty-high mill based on orthogonal experiment: China, CN202111566864.6[P]. 2021-12-20. Summary of the Invention

[0009] This paper presents a method for predicting asymmetric strip shape for a 20-high mill based on a reverse iteration method. This method uses a roll system elastic deformation model to derive a formula for rolling pressure distribution, while simultaneously using a plastic deformation model to calculate the lateral distribution of strip exit thickness. Despite using a large relaxation factor for iterative calculations, computational stability is maintained, and overall computation speed is increased.

[0010] The technical means adopted in the present invention are as follows:

[0011] A method for predicting asymmetric flatness of a twenty-high mill based on a reverse iteration method comprises the following steps:

[0012] Step 1: Obtain the basic equipment parameters of the twenty-high mill and the rolling process parameters of typical specifications of products;

[0013] Step 2: Divide the roller and the strip into units, which are t units in total; the coordinate of the width center point of each unit is y i , i=1,2,…,t, each unit width is Δy i , i=1,2,…,t;

[0014] Step 3: Calculate the deflection influence coefficient of each roller;

[0015] Step 4: Preset the initial value h of the strip outlet thickness distribution 1i ;

[0016] Step 5: Calculate the flattening influence coefficient between each roll and the flattening influence coefficient between the strip and the work roll;

[0017] Step 6: Derive the rolling pressure distribution formula based on the roll elastic deformation model;

[0018] Step 7: Combine the deformation coordination equation between the rolls with the force and moment balance equation and the formula derived in step 6. The number of unknowns is consistent with the number of equations. Calculate the pressure distribution between the rolls, the rigid displacement, and the rolling pressure distribution.

[0019] Step 8: Determine whether the inequality max|q′-q|<0.01 N / mm holds. If not, set q=q+0.1(q′-q) and proceed to step 5. If so, proceed to step 9. Where q′ represents the calculated value of the inter-roller pressure, and q represents the iterative value of the inter-roller pressure.

[0020] Step 9: Calculate the metal lateral flow by using the strip element variation method and solve the equations for the lateral displacement at the nodal outlet;

[0021] Step 10: Calculate the lateral distribution of strip outlet thickness based on the strip plastic deformation model;

[0022] Step 11: Determine whether the inequality max|h′1-h1|<0.0001mm holds. If not, set h1=h1+0.2(h′1-h1) and proceed to step 5. If so, proceed to step 12. Where h′1 represents the calculated value of the lateral distribution of the strip outlet thickness, and h1 represents the iterative value of the strip outlet thickness distribution.

[0023] Step 12: Calculate the transverse distribution of the strip's pre-tension stress σ 1i, and calculate the strip shape distribution F at the current moment i ;

[0024]

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] This paper presents a method for predicting the asymmetric flatness of a 20-high mill based on an inverse iteration method. This method uses a roll system elastic deformation model to derive a formula for rolling pressure distribution, while simultaneously using a plastic deformation model to calculate the lateral distribution of strip exit thickness. Despite using a large relaxation factor for iterative calculations, computational stability is maintained and the overall computational speed is increased. The results of this inverse iteration method for predicting the asymmetric flatness of a 20-high mill agree well with those of traditional methods, while achieving a computational speed approximately three times faster. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0028] Figure 1 It is the overall calculation flow chart of the present invention;

[0029] Figure 2 The present invention is a twenty-high mill roll system distribution angle, numbering diagram and segmented schematic diagram; wherein, (a) the number and angle of each roll; (b) the division of strip and roll system units.

[0030] Figure 3 It is a corresponding relationship diagram between the unit node line number and the unit number of the present invention;

[0031] Figure 4 1 is a transverse distribution diagram of the plate shape of the present invention, wherein (a) is Example 1; (b) is Example 2. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0033] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0034] like Figure 1-4 As shown, the present invention provides a method for predicting the asymmetric flatness of a twenty-high mill based on a reverse iteration method, comprising the following steps:

[0035] Step 1: The basic equipment parameters of the twenty-high mill include: the radius of the roller body of rollers 0 to 5, denoted as R i , i = 0 ~ 5, the elastic modulus of rollers 0 to 5 is recorded as E i , i = 0 ~ 5, the Poisson's ratio of rollers 0 to 5 is denoted as υ i , i=0~5, the distance between the two sides of the support point is L s , No. 0 roller body length L w , No. 1 roller body length L m1 , 2nd and 3rd roller body length L m2 , 4, 5 roller body length L b The angle between the line connecting the center points of the cross sections of rollers 0 and 1 and the horizontal direction is α, the angle between the line connecting the center points of the cross sections of rollers 1 and 3 and the vertical direction is δ, the angle between the line connecting the center points of the cross sections of rollers 1 and 2 and the horizontal direction is β, the angle between the line connecting the center points of the cross sections of rollers 3 and 4 and the horizontal direction is θ, and the angle between the line connecting the center points of the cross sections of rollers 2 and 4 and the vertical direction is The angle between the line connecting the cross-section center points of roller No. 2 and roller No. 5 and the horizontal direction is γ, as shown in the following example: Figure 2 (a) Shown. Roll crown ΔD of roller No. 0 and roller No. 1 01i , Roller crown ΔD of Roller No. 1 and Roller No. 2 12i , Roller crown ΔD of Roller No. 1 and Roller No. 3 13i , roller crown ΔD of roller No. 2 and roller No. 4 24i , roller crown ΔD of No. 2 and No. 5 rollers 25i , roller crown ΔD of roller No. 3 and roller No. 4 34i The pressure between the rollers of the lower roller system and the upper roller system is marked with x on the upper subscript, which can be obtained by analogy, so I will not go into details.

[0036] The rolling process parameters of the typical specifications of the products include the average thickness of the incoming strip Width B, strip elastic modulus E s , Poisson's ratio of the strip υ s , average post-tensioning stress of the strip Average pre-tension stress of strip The allowable error of the pressure between the rollers is ε1, the allowable error of the strip outlet thickness is ε2, the pressure relaxation factor between the rollers is χ1, and the strip outlet thickness relaxation factor is χ2.

[0037] Step 2: The origin of the coordinate is selected at the midpoint of the strip. Divide the roller and the strip into units, a total of t units. The coordinate of the center point of each unit width is y i (i=1,2,…,t), each unit width is Δy i (i=1,2,…,t). Among them, the starting unit number of the contact part between roller 4 and roller 2 is t1, and the ending unit number is t2; the starting unit number of the contact part between roller 2 and roller 1 is t3, and the ending unit number is t4; the starting unit number of the contact part between roller 0 and the strip is t5, and the ending unit number is t6. Figure 2 (b) When calculating the plastic deformation of the strip, the outlet lateral displacement of the strip unit node line needs to be taken as an unknown quantity. Therefore, the strip unit node lines are renumbered, as shown in Figure 3 The two node lines corresponding to unit t5 are numbered 0 and 1, and the two node lines corresponding to unit t6 are numbered n-1 and n, (n=t6-t5+1). The node line numbers of other units can be obtained by analogy.

[0038] Step 3: Calculate the deflection influence coefficient of each roller;

[0039] Step 4: Given the initial value h of the strip outlet thickness distribution 1i ;

[0040] Step 5: Calculate the flattening influence coefficient between each roll and the flattening influence coefficient between the strip and the work roll;

[0041] Step 6: According to the roller elastic deformation model, the following formula is derived:

[0042]

[0043] Step 7: Combine the deformation coordination equation between the rolls with the force and moment balance equation and the formula derived in step 6. The number of unknowns is consistent with the number of equations. Calculate the pressure distribution between the rolls, the rigid displacement, and the rolling pressure distribution.

[0044] First list 0 and 1, 0 x with 1 x ,1 and 2,1 x and 2 x , 1 and 3, 1x and 3 x ,2 and 4,2 x with 4 x , 2 and 5, 2 x and 5 x ,3 and 4,3 x with 4 x The deformation coordination equation between rollers in the direction of the line connecting the center points of the cross section is:

[0045]

[0046] Among them, f Xi represents the deflection of the X roller and the contacting rollers in the direction of the line connecting the center points of the cross section, f 4i is the arbitrary unit deflection of roller No. 4 in the vertical direction, ΔD XYi It represents the original gap or crown between roller X and roller Y on unit i, γ XYi It represents the elastic flattening influence coefficient of roller X and roller Y on unit i.

[0047] 0, 0 x , 1, 1 x The force and moment balance equation of roller No. is:

[0048]

[0049] 2, 2 x ,3,3 x The force and moment balance equation of roller No. is:

[0050]

[0051] Step 8: Determine whether the inequality max|q′-q|<0.01N / mm holds; if not, set q=q+0.1(q′-q) and proceed to step 5; if so, proceed to step 9;

[0052] Step 9: Calculate the metal lateral flow by using the strip element variation method and solve the equations for the lateral displacement at the nodal outlet;

[0053]

[0054] Among them, u0, u1, ...u n They represent the lateral displacement of the strip unit node line outlet, which is an unknown quantity; They are respectively related to unit width, strip elastic modulus, strip Poisson's ratio, strip shear deformation resistance, neutral point thickness, work roll elastic flattening radius, friction coefficient, average friction stress of contact surface in deformation zone, thickness before rolling, reduction, deformation zone length, and stress state coefficient.

[0055] Step 10: Calculate the lateral distribution of strip outlet thickness based on the strip plastic deformation model;

[0056]

[0057] in, Respectively represent the average thickness of the strip at the inlet and outlet, F i It is related to the unit width, strip elastic modulus, strip Poisson's ratio, neutral point thickness, average friction stress of the contact surface in the deformation zone, reduction, strip shear deformation resistance and deformation zone length.

[0058] Step 11: Determine whether the inequality max|h′1-h1|<0.0001mm holds true; if not, set h1=h1+0.2(h′1-h1) and proceed to step 5; if so, proceed to step 12;

[0059] Step 12: Calculate the transverse distribution of the strip's pre-tension stress σ 1i , and calculate the strip shape distribution F at the current moment i ;

[0060]

[0061] Example 1

[0062] Take a certain factory's twenty-high rolling mill as an example, according to Figure 1 The overall calculation flow chart of the asymmetric plate shape prediction method of the twenty-high rolling mill based on the reverse iteration method is shown. First, in step 1, the basic equipment parameters of the twenty-high rolling mill are collected: the roller body radius of roller No. 0 R0 = 31.75mm, the roller body radius of roller No. 1 R1 = 51mm, the roller body radius of roller No. 2 R2 = 86.5mm, the roller body radius of roller No. 3 R3 = 86.5mm, the roller body radius of roller No. 4 R4 = 150mm, the roller body radius of roller No. 5 R5 = 150mm, the elastic modulus of roller No. 0 E0 = 540GPa, the roller body radius of roller No. 1 Roller elastic modulus E1 = 210GPa, roller elastic modulus E2 = 210GPa, roller elastic modulus E3 = 210GPa, roller elastic modulus E4 = 210GPa, roller elastic modulus E5 = 210GPa, roller Poisson's ratio v0 = 0.3, roller Poisson's ratio v1 = 0.3, roller Poisson's ratio v2 = 0.3, roller Poisson's ratio v3 = 0.3, roller Poisson's ratio υ4 = 0.3, roller Poisson's ratio υ5 = 0.3, left and right pressing support distance L s =1800mm, No. 0 roller body length L w =1444mm, roller length L of No. 1 roller m1 =1580mm, roller length L for rollers 2 and 3 m2 =1444mm, roller length L of No. 4 and No. 5 rollers b=1312mm, the angle α between the line connecting the cross-section center points of roller 0 and roller 1 and the horizontal direction is 49.84°, the angle δ between the line connecting the cross-section center points of roller 1 and roller 3 and the vertical direction is 22.84°, the angle β between the line connecting the cross-section center points of roller 1 and roller 2 and the horizontal direction is 29.6°, the angle θ between the line connecting the cross-section center points of roller 3 and roller 4 and the horizontal direction is 48.53°, the angle between the line connecting the cross-section center points of roller 2 and roller 4 and the vertical direction is 48.53°, the angle The angle γ between the line connecting the cross-section center points of roller No. 2 and roller No. 5 and the horizontal direction is 13.11°. Figure 2 (a) Shown. Roll crown ΔD of roller No. 0 and roller No. 1 01i , Roller crown ΔD of Roller No. 1 and Roller No. 2 12i , Roller crown ΔD of Roller No. 1 and Roller No. 3 13i , roller crown ΔD of roller No. 2 and roller No. 4 24i , roller crown ΔD of No. 2 and No. 5 rollers 25i , roller crown ΔD of roller No. 3 and roller No. 4 34i The pressure between the rollers of the lower roller system and the upper roller system is marked with x on the upper subscript, which can be obtained by analogy, so I will not go into details.

[0063] At the same time, in step 1, the rolling process parameters of typical specifications of products are collected, mainly including the average thickness of the incoming strip Width B = 1039 mm, strip elastic modulus E s =194GPa, Poisson's ratio of the strip υ s =0.3, average post-tension stress of the strip Average pre-tension stress of strip The allowable error of the pressure between the rollers ε1 = 0.01N / mm, the allowable error of the strip outlet thickness ε2 = 0.0001mm, the pressure relaxation factor between the rollers χ1 = 0.5, and the strip outlet thickness relaxation factor χ2 = 0.2.

[0064] Then, in step 2, the unit division is performed, and the strip and roller system unit division is as follows Figure 2 (b) The origin of the coordinate is selected at the midpoint of the strip. The roller and the strip are divided into 181 units. The coordinate of the center point of each unit width is y i (i=1,2,…,181), each unit width is Δy i (i=1,2,…,181). Among them, the starting unit number of the contact part between roller 4 and roller 2 is 14, and the ending unit number is 168; the starting unit number of the contact part between roller 2 and roller 1 is 1, and the ending unit number is 181; the starting unit number of the contact part between roller 0 and the strip is 26, and the ending unit number is 156. When calculating the plastic deformation of the strip, the outlet lateral displacement of the strip unit node line needs to be taken as an unknown quantity. Therefore, the strip unit node lines are renumbered, such as Figure 3As shown. The two node lines corresponding to unit 26 are numbered 0 and 1, the two node lines corresponding to unit 156 are numbered 130 and 131, and the node line numbers of other units can be obtained by analogy;

[0065] Step 3: Calculate the deflection influence coefficient of each roller;

[0066] Step 4: Given the initial value h of the strip outlet thickness distribution 1i ;

[0067] Step 5: Calculate the flattening influence coefficient between each roll and the flattening influence coefficient between the strip and the work roll;

[0068] Step 6: According to the roller elastic deformation model, the following formula is derived:

[0069]

[0070]

[0071] Step 7: Combine the deformation coordination equation between the rolls with the force and moment balance equation and the formula derived in step 6. The number of unknowns is consistent with the number of equations. Calculate the pressure distribution between the rolls, the rigid displacement, and the rolling pressure distribution.

[0072] First list 0 and 1, 0 x with 1 x ,1 and 2,1 x and 2 x , 1 and 3, 1 x and 3 x ,2 and 4,2 x with 4 x , 2 and 5, 2 x and 5 x ,3 and 4,3 x with 4 x The deformation coordination equation between rollers in the direction of the line connecting the center points of the cross section is:

[0073]

[0074] 0, 0 x , 1, 1 x The force and moment balance equation of roller No. is:

[0075]

[0076] 2, 2 x ,3,3 x The force and moment balance equation of roller No. is:

[0077]

[0078] Then, in step 8, determine whether the inequality max|q′-q|<0.01 holds. The inequality 2596.2<0.01 obviously does not hold. q=q+0.1(q′-q), so go to step 5 and loop until the inequality 0.008<0.01 holds, then go to step 9.

[0079] Then, in step 9, the metal lateral flow is calculated by the strip element variation method, and the equations for the lateral displacement at the node outlet are solved;

[0080]

[0081] Then, in step 10, the lateral distribution of the strip exit thickness is calculated based on the strip plastic deformation model;

[0082]

[0083] Then, in step 11, determine whether the inequality max|h′1-h1|<0.0001mm holds. The inequality 0.0322<0.0001 is obviously not true. h1=h1+0.2(h′1-h1). Go to step 5 and loop until the inequality 0.00009<0.0001 holds, then go to step 12.

[0084] Finally, in step 12, the transverse distribution of the strip's pre-tension stress σ is calculated. 1i , and calculate the strip shape distribution F at the current moment i ,See Figure 4 (a).

[0085]

[0086] Example 2

[0087] Take a certain factory's twenty-high rolling mill as an example, according to Figure 1The overall calculation flow chart of the asymmetric plate shape prediction method of the twenty-high rolling mill based on the reverse iteration method is shown. First, in step 1, the basic equipment parameters of the twenty-high rolling mill are collected: the roller body radius of roller No. 0 R0 = 31.75mm, the roller body radius of roller No. 1 R1 = 51mm, the roller body radius of roller No. 2 R2 = 86.5mm, the roller body radius of roller No. 3 R3 = 86.5mm, the roller body radius of roller No. 4 R4 = 150mm, the roller body radius of roller No. 5 R5 = 150mm, the elastic modulus of roller No. 0 E0 = 540GPa, the roller body radius of roller No. 1 Roller elastic modulus E1 = 210GPa, roller elastic modulus E2 = 210GPa, roller elastic modulus E3 = 210GPa, roller elastic modulus E4 = 210GPa, roller elastic modulus E5 = 210GPa, roller Poisson's ratio v0 = 0.3, roller Poisson's ratio v1 = 0.3, roller Poisson's ratio v2 = 0.3, roller Poisson's ratio v3 = 0.3, roller Poisson's ratio υ4 = 0.3, roller Poisson's ratio υ5 = 0.3, left and right pressing support distance L s =1800mm, No. 0 roller body length L w =1444mm, roller length L of No. 1 roller m1 =1580mm, roller length L for rollers 2 and 3 m2 =1444mm, roller length L of No. 4 and No. 5 rollers b =1312mm, the angle α between the line connecting the cross-section center points of roller 0 and roller 1 and the horizontal direction is 49.84°, the angle δ between the line connecting the cross-section center points of roller 1 and roller 3 and the vertical direction is 22.84°, the angle β between the line connecting the cross-section center points of roller 1 and roller 2 and the horizontal direction is 29.6°, the angle θ between the line connecting the cross-section center points of roller 3 and roller 4 and the horizontal direction is 48.53°, the angle between the line connecting the cross-section center points of roller 2 and roller 4 and the vertical direction is 48.53°, the angle The angle γ between the line connecting the cross-section center points of roller No. 2 and roller No. 5 and the horizontal direction is 13.11°. Figure 2 (a) Shown. Roll crown ΔD of roller No. 0 and roller No. 1 01i , Roller crown ΔD of Roller No. 1 and Roller No. 2 12i , Roller crown ΔD of Roller No. 1 and Roller No. 3 13i , roller crown ΔD of roller No. 2 and roller No. 4 24i , roller crown ΔD of No. 2 and No. 5 rollers 25i , roller crown ΔD of roller No. 3 and roller No. 4 34i The pressure between the rollers of the lower roller system and the upper roller system is marked with x on the upper subscript, which can be obtained by analogy, so I will not go into details.

[0088] At the same time, in step 1, the rolling process parameters of typical specifications of products are collected, mainly including the average thickness of the incoming strip Width B = 1035 mm, strip elastic modulus E s =194GPa, Poisson's ratio of the strip υs =0.3, average post-tension stress of the strip Average pre-tension stress of strip The allowable error of the pressure between the rollers ε1 = 0.01N / mm, the allowable error of the strip outlet thickness ε2 = 0.0001mm, the pressure relaxation factor between the rollers χ1 = 0.5, and the strip outlet thickness relaxation factor χ2 = 0.2.

[0089] Then, in step 2, the unit division is performed, and the strip and roller system unit division is as follows Figure 2 (b) The origin of the coordinate is selected at the midpoint of the strip. The roller and the strip are divided into 181 units. The coordinate of the center point of each unit width is y i (i=1,2,…,181), each unit width is Δy i (i=1,2,…,181). Among them, the starting unit number of the contact part between roller 4 and roller 2 is 14, and the ending unit number is 168; the starting unit number of the contact part between roller 2 and roller 1 is 1, and the ending unit number is 181; the starting unit number of the contact part between roller 0 and the strip is 26, and the ending unit number is 156. When calculating the plastic deformation of the strip, the outlet lateral displacement of the strip unit node line needs to be taken as an unknown quantity. Therefore, the strip unit node lines are renumbered, such as Figure 3 As shown. The two node lines corresponding to unit 26 are numbered 0 and 1, the two node lines corresponding to unit 156 are numbered 130 and 131, and the node line numbers of other units can be obtained by analogy;

[0090] Step 3: Calculate the deflection influence coefficient of each roller;

[0091] Step 4: Given the initial value h of the strip outlet thickness distribution 1i ;

[0092] Step 5: Calculate the flattening influence coefficient between each roll and the flattening influence coefficient between the strip and the work roll;

[0093] Step 6: According to the roller elastic deformation model, the following formula is derived:

[0094]

[0095] Step 7: Combine the deformation coordination equation between the rolls with the force and moment balance equation and the formula derived in step 6. The number of unknowns is consistent with the number of equations. Calculate the pressure distribution between the rolls, the rigid displacement, and the rolling pressure distribution.

[0096] First list 0 and 1, 0 x with 1 x ,1 and 2,1 x and 2 x , 1 and 3, 1 x and 3 x,2 and 4,2 x with 4 x , 2 and 5, 2 x and 5 x ,3 and 4,3 x with 4 x The deformation coordination equation between rollers in the direction of the line connecting the center points of the cross section is:

[0097]

[0098] 0, 0 x , 1, 1 x The force and moment balance equation of roller No. is:

[0099]

[0100] 2, 2 x ,3,3 x The force and moment balance equation of roller No. is:

[0101]

[0102] Then, in step 8, determine whether the inequality max|q′-q|<0.01 holds. The inequality 2292.56<0.01 obviously does not hold. q=q+0.1(q′-q), so go to step 5 and loop until the inequality 0.0091<0.01 holds, then go to step 9.

[0103] Then, in step 9, the metal lateral flow is calculated by the strip element variation method, and the equations for the lateral displacement at the node outlet are solved;

[0104]

[0105] Then, in step 10, the lateral distribution of the strip exit thickness is calculated based on the strip plastic deformation model;

[0106]

[0107] Then, in step 11, determine whether the inequality max|h′1-h1|<0.0001mm holds. The inequality 0.0016<0.0001 is obviously not true. h1=h1+0.2(h′1-h1). Go to step 5 and loop until the inequality 0.00009<0.0001 holds, then go to step 12.

[0108] Finally, in step 12, the transverse distribution of the strip's pre-tension stress σ is calculated. 1i , and calculate the strip shape distribution F at the current moment i ,See Figure 4 (b).

[0109]

[0110] The serial numbers of the above embodiments of the present invention are for description only and do not represent the advantages or disadvantages of the embodiments.

[0111] In the above embodiments of the present invention, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0112] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only exemplary. For example, the division of the units can be a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0113] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0114] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0115] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk, etc. Various media that can store program codes.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for predicting asymmetric flatness of a twenty-high mill based on a reverse iteration method, characterized in that: The following steps are involved: Step 1: Obtain the basic equipment parameters of the twenty-high mill and the rolling process parameters of typical specifications of products; Step 2: Divide the roller and the strip into units, which are t units in total; the coordinate of the width center point of each unit is y i , i=1,2,…,t, each unit width is Δy i , i=1,2,…,t; Step 3: Calculate the deflection influence coefficient of each roller; Step 4: Preset the initial value h of the strip outlet thickness distribution 1i ; Step 5: Calculate the flattening influence coefficient between each roll and the flattening influence coefficient between the strip and the work roll; Step 6: Derive the rolling pressure distribution formula based on the roll elastic deformation model; Step 7: Combine the deformation coordination equation between the rolls with the force and moment balance equation and the formula derived in step 6. The number of unknowns is consistent with the number of equations. Calculate the pressure distribution between the rolls, the rigid displacement, and the rolling pressure distribution. Step 8: Determine whether the inequality max|q′-q|<0.01 N / mm holds. If not, set q=q+0.1(q′-q) and proceed to step 5. If so, proceed to step 9. Where q′ represents the calculated value of the inter-roller pressure, and q represents the iterative value of the inter-roller pressure. Step 9: Calculate the metal lateral flow by using the strip element variation method and solve the equations for the lateral displacement at the nodal outlet; Step 10: Calculate the lateral distribution of strip outlet thickness based on the strip plastic deformation model; Step 11: Determine whether the inequality max|h′1-h1|<0.0001mm holds. If not, set h1=h1+0.2(h′1-h1) and proceed to step 5. If so, proceed to step 12. Where h′1 represents the calculated value of the lateral distribution of the strip outlet thickness, and h1 represents the iterative value of the strip outlet thickness distribution. Step 12: Calculate the transverse distribution of the strip's pre-tension stress σ 1i , and calculate the strip shape distribution F at the current moment i ; 2. The method for predicting asymmetric flatness of a twenty-high mill based on reverse iterative analysis according to claim 1, characterized in that: In step 1, the basic equipment parameters of the twenty-high mill include: the radius of the roller body of rollers 0 to 5, denoted as R i , i = 0 ~ 5, the elastic modulus of rollers 0 to 5 is recorded as E i , i = 0 ~ 5, the Poisson's ratio of rollers 0 to 5 is denoted as υ i , i=0~5, the distance between the two sides of the support point is L s , No. 0 roller body length L w , No. 1 roller body length L m1 , 2nd and 3rd roller body length L m2 , 4, 5 roller body length L b The angle between the line connecting the center points of the cross sections of rollers 0 and 1 and the horizontal direction is α, the angle between the line connecting the center points of the cross sections of rollers 1 and 3 and the vertical direction is δ, the angle between the line connecting the center points of the cross sections of rollers 1 and 2 and the horizontal direction is β, the angle between the line connecting the center points of the cross sections of rollers 3 and 4 and the horizontal direction is θ, and the angle between the line connecting the center points of the cross sections of rollers 2 and 4 and the vertical direction is The angle between the line connecting the cross-section center points of roller No. 2 and roller No. 5 and the horizontal direction is γ.

3. The method for predicting asymmetric flatness of a twenty-high mill based on the reverse iteration method according to claim 1, characterized in that: In step 1, the rolling process parameters of the typical specification products include: the average thickness of the incoming strip Width B, strip elastic modulus E s 、Poisson's ratio of strip υ s , average post-tensioning stress of strip Average pre-tension stress of strip The allowable error of the pressure between the rollers ε1, the allowable error of the strip exit thickness ε2, the relaxation factor of the pressure between the rollers χ1 and the relaxation factor of the strip exit thickness χ2.

4. The method for predicting asymmetric flatness of a twenty-high mill based on the reverse iteration method according to claim 1, characterized in that: In step 2, the coordinate origin is selected at the midpoint of the strip; the roller and the strip are divided into units, which are divided into t units in total; the coordinate of the center point of the width of each unit is y i , i=1,2,…,t, each unit width is Δy i , i=1,2,…,t; Wherein, t1 represents the starting unit of the contact portion between roller 4 and roller 2, and t2 represents the ending unit of the contact portion between roller 4 and roller 2; t3 represents the starting unit of the contact portion between roller 2 and roller 1, and t4 represents the ending unit of the contact portion between roller 2 and roller 1; t5 represents the starting unit of the contact portion between roller 0 and the strip, and t6 represents the ending unit of the contact portion between roller 0 and the strip; When calculating the plastic deformation of the strip, the outlet lateral displacement of the strip unit node line is taken as an unknown quantity. Therefore, the strip unit node lines are renumbered. The two node lines corresponding to the starting unit t5 of the contact part between roller No. 0 and the strip are numbered 0 and 1, and the two node lines corresponding to the ending unit t6 of the contact part between roller No. 0 and the strip are numbered n-1 and n, n=t6-t5+1. The node line numbers of other units can be obtained by analogy.

5. The method for predicting asymmetric flatness of a twenty-high mill based on the reverse iteration method according to claim 1, characterized in that: In step 6, the following formula is derived based on the roller system elastic deformation model: Among them, α wsij Indicates the flattening influence coefficient between the strip and the No. 0 roller; p i represents the rolling pressure distribution; s0 represents the no-load roll gap value; d1 and d2 represent the left and right rigid displacements of roller 0, respectively; Represents 0 respectively x The left and right rigid displacement of roller No. ΔD 0i , ΔD 0i x Respectively represent roller 0, x Roller profile distribution value of No. roller.

6. The method for predicting asymmetric flatness of a twenty-high mill based on the reverse iteration method according to claim 1, characterized in that: In step 9, the expression for calculating the metal lateral flow by the strip element variation method is: Among them, u0, u1, ...u n They represent the lateral displacement of the strip unit node line outlet, which is an unknown quantity; They are respectively related to unit width, strip elastic modulus, strip Poisson's ratio, strip shear deformation resistance, neutral point thickness, work roll elastic flattening radius, friction coefficient, average friction stress of contact surface in deformation zone, thickness before rolling, reduction, deformation zone length, and stress state coefficient.

7. The method for predicting asymmetric flatness of a twenty-high mill based on the reverse iteration method according to claim 1, characterized in that: In step 10, the lateral distribution of the strip outlet thickness is calculated according to the strip plastic deformation model: in, Respectively represent the average thickness of the strip at the inlet and outlet, F i It is related to the unit width, strip elastic modulus, strip Poisson's ratio, neutral point thickness, average friction stress of the contact surface in the deformation zone, reduction, strip shear deformation resistance and deformation zone length.

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