CN113042571B - An optimization method for tension and elongation of a single-frame leveling unit - Google Patents

Abstract

The invention relates to a method for optimizing the tension and the elongation of a single-frame temper mill, belonging to the technical field of cold rolling. The technical scheme of the invention is as follows: summarizing production parameters of a single-rack leveling unit, and calculating an optimal front and rear tension distribution state of the unit by integrating various factors; taking the shape of the outlet strip and the slip factor as a target function, and controlling the actual elongation and the set elongation within a certain range as constraint conditions; setting initial front and back tension and elongation, and obtaining production parameters meeting plate shape control and rolling stability through multiple iterations, and meeting the requirements of two important indexes. The invention has the beneficial effects that: compared with the conventional manual adjustment and plate shape feedback adjustment methods, the tension calculation and setting method is closer to the reality, better meets the requirements of field production, and can further improve the plate shape.

Description

A method for optimizing tension and elongation of a single-frame leveling machine

Technical Field

The invention relates to a tension and elongation optimization method, belonging to the technical field of cold rolling.

Background Art

Flattening treatment plays a very important role in the production process of cold-rolled plates and strips. The single-stand flattening unit is mainly used for the flattening of cold-rolled annealed coils. Since the mechanical properties and surface quality of the strip after annealing have not yet reached the index requirements, the flattening process is needed to improve the plate shape and the mechanical properties of the strip.

During the flat rolling process of strip steel, the quality of the strip shape is affected by many factors, among which the slippage during the rolling process seriously endangers the stability of the rolling process, leading to fluctuations in parameters such as rolling force and tension, which in turn induces risks such as roll strangulation and strip breakage. This makes it particularly important to reasonably avoid or predict slippage for the rolling of high-quality strip steel. By collecting and regressing the production data of specific units, accurately predicting the slippage of the rolling mill and making precise adjustments can significantly improve the strip shape.

Since the setting of the unit tension in the strip production process is usually controlled based on experience, the tension setting is not accurate enough and the optimal plate shape under a specific production condition cannot be achieved. Therefore, the precise setting method of the tension of the leveling unit also closely affects the regulation of the plate shape. At present, the research on the rolling process related to the leveling unit is relatively mature abroad, and China has also made breakthroughs in the overall layout and design of the process flow, but there is still a lack of innovative methods and practical experience in key areas. There are no key methods and guiding opinions in foreign literature, so it is necessary to conduct in-depth research and multiple experiments in areas such as accurate tension optimization setting and optimization of elongation under rolling stability and plate shape control conditions, deeply analyze the influencing factors between various parameters, and innovate methods on the basis of improving the strip shape. Combined with actual production information, a tension and elongation optimization method with rolling stability and plate shape control as the goal is proposed, and finally the optimization and improvement of the on-site strip leveling process is achieved.

Summary of the invention

The purpose of the present invention is to provide a method for optimizing the tension and elongation of a single-frame leveling machine unit. By summarizing the production parameters of the leveling machine unit, the optimal front and rear tension distribution state of the unit is calculated by comprehensively considering various factors; the equipment and process characteristics of the single-frame leveling machine unit are fully considered, the export strip shape and slip factor are used as objective functions, and the actual elongation and the set elongation are controlled within a certain range as constraints; by setting the initial front and rear tensions and elongation, multiple iterations are performed to obtain production parameters that meet the requirements of plate shape control and rolling stability, while meeting the requirements of the two important indicators, which has important guiding significance for on-site production. Compared with conventional manual adjustment and plate shape feedback adjustment methods, the tension calculation and setting method is closer to reality, more in line with the needs of on-site production, and can further improve the plate shape, effectively solving the above-mentioned problems existing in the background technology.

The technical solution of the present invention is: a method for optimizing the tension and elongation of a single-frame leveling unit, comprising the following steps:

(a) Collect the equipment characteristic parameters of a single-frame leveling machine group;

(b) Collect the key strip rolling process parameters for setting the metal model parameters comprehensively, including: the lateral distribution value of the incoming strip thickness _Hi , the strip elongation ε, the rolling speed V, the front and rear tensions _T0 and _T1 of the strip, the strip outlet thickness _h1 , the working roll diameter D, the strip width B and the strip yield limit _σs .

(c) Collecting process characteristic parameters, mainly including: the maximum allowable plate shape SHAPE*; the maximum and minimum elongation values ε _max , ε _min ;

(d) setting the bending roll force to the base state;

(e) defining the initial value of the front tension T ₀₁ , the initial value of the rear tension T ₀₀ , and the setting value ε of the elongation;

(f) Calculate the actual value of elongation ε ^* under the current working condition;

若偏差绝对值小于延伸率设定值的1％，则立即进入步骤(h)，否则返回步骤(e)，调整延伸率设定值ε；(g) Calculate the deviation between the actual elongation value ε ^* and the set elongation value ε under the current working conditions

If the absolute value of the deviation is less than 1% of the set value of the elongation, the process immediately proceeds to step (h); otherwise, the process returns to step (e) to adjust the set value of the elongation;

L为轧制变形区中轧辊与带材接触弧长度，

B为带材宽度，a₀、a₁为平整钢种与工况影响系数，σ_p为当量变形抗力，σ_p＝k₃·(σ_s+a·lg 1000·e)-(k₁·T₁+k₂·T₀)，D为工作辊直径，ε为带材延伸率，μ为摩擦系数，h₀为带材入口厚度，e为变形速率，k₁、k₂为前后张力加权系数，k₃为变形抗力影响系数，σ_s为带材屈服强度，a为应变速率系数；(h) Calculate the rolling pressure P under the current working condition, P = f·L; where f is the unit rolling force,

L is the contact arc length between the roller and the strip in the rolling deformation zone,

B is the strip width, a ₀ and a ₁ are the influence coefficients of flat steel grade and working conditions, σ _p is the equivalent deformation resistance, σ _p =k ₃ ·(σ _s +a·lg 1000·e)-(k ₁ ·T ₁ +k ₂ ·T ₀ ), D is the working roll diameter, ε is the strip elongation, μ is the friction coefficient, h ₀ is the strip entrance thickness, e is the deformation rate, k ₁ and k ₂ are the weighted coefficients of the front and rear tensions, k ₃ is the influence coefficient of deformation resistance, σ _s is the strip yield strength, and a is the strain rate coefficient;

其中，σ₁(x)为出口带材横向各点单位张力，σ₁为出口侧总张力，B为带材宽度，

为带材出口平均厚度，h(x)为带材出口厚度横向分布值，

为带材入口平均厚度，H(x)为带材入口厚度横向分布值，

为表示来料板形的长度平均值，L(x)为表示来料板形的长度横向分布值，Δu'为带材横向位移增量横向分布函数；(i) Calculate the lateral distribution of the front tension of the finished strip under the condition of certain incoming materials; the lateral distribution of the front tension can be expressed as:

Among them, σ ₁ (x) is the unit tension at each point in the transverse direction of the outlet strip, σ ₁ is the total tension on the outlet side, B is the strip width,

is the average thickness of the strip at the exit, h(x) is the transverse distribution value of the strip thickness at the exit,

is the average thickness of the strip at the entrance, H(x) is the lateral distribution value of the strip entrance thickness,

is the average length of the incoming material shape, L(x) is the lateral distribution value of the length of the incoming material shape, and Δu' is the lateral distribution function of the lateral displacement increment of the strip;

E、ν为工作辊的杨氏模量和泊松比；(j) Calculate the outlet flatness value I of the balancing unit under the current rolling pressure,

E and ν are Young’s modulus and Poisson’s ratio of the working roll;

其中，i为带钢横向条元数，I_i为带钢横向各条元板形分布值，α、β、γ为加权系数，此处取α＝0.4、β＝0.3、γ＝0.3，ψ为当前工况下的打滑因子，

其中工作辊压扁半径

Δh为压下量，R为工作辊半径，E、ν为工作辊的杨氏模量和泊松比；(k) Construct the objective function F(X), let

Among them, i is the number of transverse strips of the strip, I _i is the plate shape distribution value of each transverse strip of the strip, α, β, γ are weighting coefficients, where α = 0.4, β = 0.3, γ = 0.3, ψ is the slip factor under the current working condition,

The flattening radius of the working roll

Δh is the reduction, R is the radius of the working roll, E and ν are the Young's modulus and Poisson's ratio of the working roll;

(l) finding the extreme value, i.e., the minimum value, of the objective function F(X); if the result converges, immediately proceeding to step (m); otherwise, returning to step (e) to modify the initial setting values of the front and rear tensions;

时的前后张力设定值和延伸率设定值；(m) During the optimization process, when the following relationship exists between a function value F(X _i ) and the next function value F(X _i+1 ) calculated, the optimization can be stopped to obtain the optimal solution, that is, satisfying

The front and rear tension setting values and elongation setting values;

(n) Output the above-mentioned front and rear tension setting values and elongation setting values that meet the conditions, and the optimization process ends.

与

机架工作辊上机粗糙度Ra₁、机架工作辊轧制公里数L、机架轧制力允许最大值P_max、出口板面粗糙度轧辊复印部分中机架带材的入口厚度影响线性系数与非线性系数分别为α_h,α′_h、机架出口板面粗糙度遗传部分中机架带材的入口厚度影响系数β_h、机架出口板面粗糙度遗传部分与复印部分中末机架带材的材质影响系数α_k,β_k、机架出口板面粗糙度遗传部分与轧辊复印部分中延伸率影响系数α_ε,β_ε和机组设备特性影响参数η₁,η₂。In the step (a), the equipment characteristic parameters of the single-stand leveling unit include: the diameter D of the working roll of the stand, the original roll profile distribution values ΔD _wi and ΔD _bi of the working roll and the support roll, the roll body lengths L ₁ and L ₂ of the working roll and the support roll, the bending cylinder distance l ₂ of the working roll, the center moment of the pressing screw l ₁ , and the maximum positive and negative bending forces allowed for the working roll bending

and

The machine roughness Ra ₁ of the stand working roll, the rolling mileage L of the stand working roll, the maximum allowable rolling force P _max of the stand, the linear coefficient and nonlinear coefficient of the entrance thickness of the stand strip in the roller copy part of the exit plate surface roughness are α _h , α′ _h respectively, the entrance thickness influence coefficient of the stand strip in the genetic part of the stand exit plate surface roughness β _h , the material influence coefficient of the last stand strip in the genetic part and copy part of the stand exit plate surface roughness α _k , β _k , the elongation influence coefficient α _ε , β _ε in the genetic part of the stand exit plate surface roughness and the roller copy part and the unit equipment characteristic influence parameters η ₁ ,η ₂ .

The beneficial effects of the present invention are as follows: by summarizing the production parameters of the leveling machine, the optimal front and rear tension distribution state of the unit is calculated by comprehensively considering various factors; the equipment and process characteristics of the single-frame leveling machine are fully considered, the export strip shape and slip factor are used as the objective function, and the actual elongation and the set elongation are controlled within a certain range as constraints; by setting the initial front and rear tensions and elongation, multiple iterations are performed to obtain production parameters that meet the requirements of plate shape control and rolling stability, while meeting the requirements of the two important indicators, which has important guiding significance for on-site production. Compared with conventional manual adjustment and plate shape feedback adjustment methods, the tension calculation and setting method is closer to reality, more in line with the needs of on-site production, and can further improve the plate shape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a flow chart of the present invention;

DETAILED DESCRIPTION

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

A method for optimizing tension and elongation of a single-frame leveling unit comprises the following steps:

(a) Collect the equipment characteristic parameters of a single-frame leveling machine group;

(b) Collect the key strip rolling process parameters for setting the metal model parameters comprehensively, including: the lateral distribution value of the incoming strip thickness _Hi , the strip elongation ε, the rolling speed V, the front and rear tensions _T0 and _T1 of the strip, the strip outlet thickness _h1 , the working roll diameter D, the strip width B and the strip yield limit _σs .

(c) Collecting process characteristic parameters, mainly including: the maximum allowable plate shape SHAPE*; the maximum and minimum elongation values ε _max , ε _min ;

(d) setting the bending roll force to the base state;

(e) defining the initial value of the front tension T ₀₁ , the initial value of the rear tension T ₀₀ , and the setting value ε of the elongation;

(f) Calculate the actual value of elongation ε ^* under the current working condition;

若偏差绝对值小于延伸率设定值的1％，则立即进入步骤(h)，否则返回步骤(e)，调整延伸率设定值ε；(g) Calculate the deviation between the actual elongation value ε ^* and the set elongation value ε under the current working conditions

If the absolute value of the deviation is less than 1% of the set value of the elongation, the process immediately proceeds to step (h); otherwise, the process returns to step (e) to adjust the set value of the elongation;

L为轧制变形区中轧辊与带材接触弧长度，

B为带材宽度，a₀、a₁为平整钢种与工况影响系数，σ_p为当量变形抗力，σ_p＝k₃·(σ_s+a·lg 1000·e)-(k₁·T₁+k₂·T₀)，D为工作辊直径，ε为带材延伸率，μ为摩擦系数，h₀为带材入口厚度，e为变形速率，k₁、k₂为前后张力加权系数，k₃为变形抗力影响系数，σ_s为带材屈服强度，a为应变速率系数；(h) Calculate the rolling pressure P under the current working condition, P = f·L; where f is the unit rolling force,

L is the contact arc length between the roller and the strip in the rolling deformation zone,

B is the strip width, a ₀ and a ₁ are the influence coefficients of flat steel grade and working conditions, σ _p is the equivalent deformation resistance, σ _p =k ₃ ·(σ _s +a·lg 1000·e)-(k ₁ ·T ₁ +k ₂ ·T ₀ ), D is the working roll diameter, ε is the strip elongation, μ is the friction coefficient, h ₀ is the strip entrance thickness, e is the deformation rate, k ₁ and k ₂ are the weighted coefficients of the front and rear tensions, k ₃ is the influence coefficient of deformation resistance, σ _s is the strip yield strength, and a is the strain rate coefficient;

其中，σ₁(x)为出口带材横向各点单位张力，σ₁为出口侧总张力，B为带材宽度，

为带材出口平均厚度，h(x)为带材出口厚度横向分布值，

为带材入口平均厚度，H(x)为带材入口厚度横向分布值，

为表示来料板形的长度平均值，L(x)为表示来料板形的长度横向分布值，Δu'为带材横向位移增量横向分布函数；(i) Calculate the lateral distribution of the front tension of the finished strip under the condition of certain incoming materials; the lateral distribution of the front tension can be expressed as:

Among them, σ ₁ (x) is the unit tension at each point in the transverse direction of the outlet strip, σ ₁ is the total tension on the outlet side, B is the strip width,

is the average thickness of the strip at the exit, h(x) is the transverse distribution value of the strip thickness at the exit,

is the average thickness of the strip at the entrance, H(x) is the lateral distribution value of the strip entrance thickness,

is the average length of the incoming material shape, L(x) is the lateral distribution value of the length of the incoming material shape, and Δu' is the lateral distribution function of the lateral displacement increment of the strip;

E、ν为工作辊的杨氏模量和泊松比；(j) Calculate the outlet flatness value I of the balancing unit under the current rolling pressure,

E and ν are Young’s modulus and Poisson’s ratio of the working roll;

其中，i为带钢横向条元数，I_i为带钢横向各条元板形分布值，α、β、γ为加权系数，此处取α＝0.4、β＝0.3、γ＝0.3，ψ为当前工况下的打滑因子，

其中工作辊压扁半径

Δh为压下量，R为工作辊半径，E、ν为工作辊的杨氏模量和泊松比；(k) Construct the objective function F(X), let

Among them, i is the number of transverse strips of the strip, I _i is the plate shape distribution value of each transverse strip of the strip, α, β, γ are weighting coefficients, where α = 0.4, β = 0.3, γ = 0.3, ψ is the slip factor under the current working condition,

The flattening radius of the working roll

Δh is the reduction, R is the radius of the working roll, E and ν are the Young's modulus and Poisson's ratio of the working roll;

(l) finding the extreme value, i.e., the minimum value, of the objective function F(X); if the result converges, immediately proceeding to step (m); otherwise, returning to step (e) to modify the initial setting values of the front and rear tensions;

时的前后张力设定值和延伸率设定值；(m) During the optimization process, when the following relationship exists between a function value F(X _i ) and the next function value F(X _i+1 ) calculated, the optimization can be stopped to obtain the optimal solution, that is, satisfying

The front and rear tension setting values and elongation setting values;

(n) Output the above-mentioned front and rear tension setting values and elongation setting values that meet the conditions, and the optimization process ends.

与

机架工作辊上机粗糙度Ra₁、机架工作辊轧制公里数L、机架轧制力允许最大值P_max、出口板面粗糙度轧辊复印部分中机架带材的入口厚度影响线性系数与非线性系数分别为α_h,α′_h、机架出口板面粗糙度遗传部分中机架带材的入口厚度影响系数β_h、机架出口板面粗糙度遗传部分与复印部分中末机架带材的材质影响系数α_k,β_k、机架出口板面粗糙度遗传部分与轧辊复印部分中延伸率影响系数α_ε,β_ε和机组设备特性影响参数η₁,η₂。In the step (a), the equipment characteristic parameters of the single-stand leveling unit include: the diameter D of the working roll of the stand, the original roll profile distribution values ΔD _wi and ΔD _bi of the working roll and the support roll, the roll body lengths L ₁ and L ₂ of the working roll and the support roll, the bending cylinder distance l ₂ of the working roll, the center moment of the pressing screw l ₁ , and the maximum positive and negative bending forces allowed for the working roll bending

and

The machine roughness Ra ₁ of the stand working roll, the rolling mileage L of the stand working roll, the maximum allowable rolling force P _max of the stand, the linear coefficient and nonlinear coefficient of the entrance thickness of the stand strip in the roller copy part of the exit plate surface roughness are α _h , α′ _h respectively, the entrance thickness influence coefficient of the stand strip in the genetic part of the stand exit plate surface roughness β _h , the material influence coefficient of the last stand strip in the genetic part and copy part of the stand exit plate surface roughness α _k , β _k , the elongation influence coefficient α _ε , β _ε in the genetic part of the stand exit plate surface roughness and the roller copy part and the unit equipment characteristic influence parameters η ₁ ,η ₂ .

Among the control factors of the strip steel produced by a single-stand skin-pass mill, for a specific type of skin-pass rolling process, parameters such as ε, V, T ₀ , T ₁ , h ₁ , D, B, σ _s are determined, and the rolling pressure depends on the steel type and the working condition influence coefficients a ₀ , a ₁ , μ. The steel type and working condition influence coefficients a ₀ , a ₁ , μ can be obtained in the slip prediction model that realizes regression of a large amount of actual production data of the steel type. Therefore, the rolling pressure is determined by the front and rear tensions. In the process of calculating the tension, the tension is actually optimized. By fully considering the equipment process characteristics and actual working conditions of different skin-pass mills, through the control of the plate shape during the rolling process and the control of rolling stability, after a large amount of field data regression and theoretical analysis, a tension and elongation optimization method with rolling stability and plate shape control as the goal is established, and the influence of skin-pass rolling process parameters is comprehensively analyzed. A set of engineering practical single-stand skin-pass mill tension and elongation optimization calculation methods are proposed.

Embodiment 1:

最大负弯辊力与

机架工作辊上机粗糙度Ra₁＝2.5μm、机架工作辊轧制公里数L＝0km、机架轧制力允许最大值P_max＝8000kN、出口板面粗糙度轧辊复印部分中机架带材的入口厚度影响线性系数与非线性系数分别为α_h＝6.556,α_h′＝1.444、机架出口板面粗糙度遗传部分中机架带材的入口厚度影响系数β_h＝6.556、机架出口板面粗糙度遗传部分与复印部分中末机架带材的材质影响系数α_k＝2.27,β_k＝－4、机架出口板面粗糙度遗传部分与轧辊复印部分中延伸率影响系数α_ε＝-127.3,β_ε＝400、机组设备特性影响参数η₁＝0.48,η₂＝0.377，带材的屈服极限σ_s＝500Mpa。；(a) Collect the equipment characteristic parameters of the single-stand skin-pass unit, mainly including: the working roll diameter D of the stand, the original roll profile distribution value of the working roll and the support roll ΔD _wi = 0, ΔD _bi = 0, the roll body length of the working roll and the support roll L ₁ = 1850mm, L ₂ = 1850mm, the cylinder distance of the working roll bending roll l ₁ = 2500mm, the center moment of the pressing screw l ₂ = 2500mm, the maximum positive roll bending force allowed for the working roll bending roll

Maximum negative bending roll force and

The machine roughness of the working roll of the stand is Ra ₁ = 2.5μm, the rolling mileage of the working roll of the stand is L = 0km, the maximum allowable rolling force of the stand is P _max = 8000kN, the linear coefficient and nonlinear coefficient of the entrance thickness of the stand strip in the roller copy part of the export plate surface roughness are α _h = 6.556, α _h ′ = 1.444, the entrance thickness influence coefficient of the stand strip in the genetic part of the export plate surface roughness of the stand is β _h = 6.556, the material influence coefficient of the last stand strip in the genetic part and copy part of the export plate surface roughness of the stand is α _k = 2.27, β _k = -4, the elongation influence coefficient in the genetic part of the export plate surface roughness of the stand and the roller copy part is α _ε = -127.3, β _ε = 400, the unit equipment characteristic influencing parameters η ₁ = 0.48, η ₂ = 0.377, and the yield limit of the strip is σ _s = 500Mpa. ;

Subsequently, in step (b), key strip rolling process parameters for comprehensively setting metal model parameters are collected, mainly including: lateral distribution value of incoming strip thickness _Hi , _Hi = {0.353, 0.353, 0.353, 0.354, 0.3554, 0.354, 0.354, 0.354, 0.355, 0.355, 0.355, 0.354, 0.354, 0.354, 0.354, 0.354, 0.354, 0.353, 0.353, 0.353}, unit: mm; strip elongation ε = 1.2%, rolling speed V = 4 m/s, strip front and rear tensions _T0 = 35 kN, _T1 = 37 kN, strip outlet thickness _h1 =0.34mm, working roll diameter D = 430mm, strip width B = 1500mm;

Then, in step (c), process characteristic parameters are collected, mainly including: the maximum allowable plate shape SHAPE*; the maximum and minimum values of elongation ε _max =1.5%, ε _min =0.8%;

Then, in step (d), the bending roll force S is set to the base state.

Then, in step (e), the initial value of the front tension T ₀₁ =36.5 kN, the initial value of the rear tension T ₀₀ =37.5 kN, and the setting value of the elongation ε =1.2% are defined;

Then, in step (f), the actual value of the elongation under the current working condition is calculated as ε ^* =1.116%;

若偏差绝对值小于延伸率设定值的1％，则立即进入步骤(h)；Then, in step (g), the deviation between the actual value of elongation ε ^* and the set value of elongation ε under the current working condition is calculated.

If the absolute value of the deviation is less than 1% of the set value of the elongation, immediately proceed to step (h);

L为轧制变形区中轧辊与带材接触弧长度，

B为带材宽度，a₀、a₁为平整钢种与工况影响系数，σ_p为当量变形抗力，σ_p＝k₃·(σ_s+a·lg 1000·e)-(k₁·T₁+k₂·T₀)，D为工作辊直径，ε为带材延伸率，μ为摩擦系数，h₀为带材入口厚度，e为变形速率，k₁、k₂为前后张力加权系数，k₃为变形抗力影响系数，σ_s为带材屈服强度，a为应变速率系数；Then, in step (h), the rolling pressure P under the current working condition is calculated, P = f·L; where f is the unit rolling force,

L is the contact arc length between the roller and the strip in the rolling deformation zone,

B is the strip width, a ₀ and a ₁ are the influence coefficients of flat steel grade and working conditions, σ _p is the equivalent deformation resistance, σ _p =k ₃ ·(σ _s +a·lg 1000·e)-(k ₁ ·T ₁ +k ₂ ·T ₀ ), D is the working roll diameter, ε is the strip elongation, μ is the friction coefficient, h ₀ is the strip entrance thickness, e is the deformation rate, k ₁ and k ₂ are the weighted coefficients of the front and rear tensions, k ₃ is the influence coefficient of deformation resistance, σ _s is the strip yield strength, and a is the strain rate coefficient;

其中，σ₁(x)为出口带材横向各点单位张力，σ₁为出口侧总张力，B为带材宽度，

为带材出口平均厚度，h(x)为带材出口厚度横向分布值，

为带材入口平均厚度，H(x)为带材入口厚度横向分布值，

为表示来料板形的长度平均值，L(x)为表示来料板形的长度横向分布值，Δu'为带材横向位移增量横向分布函数；Then, in step (i), the front tension transverse distribution of the finished strip is calculated under the conditions of the incoming material. The front tension transverse distribution can be expressed as:

Among them, σ ₁ (x) is the unit tension at each point in the transverse direction of the outlet strip, σ ₁ is the total tension on the outlet side, B is the strip width,

is the average thickness of the strip at the exit, h(x) is the transverse distribution value of the strip thickness at the exit,

is the average thickness of the strip at the entrance, H(x) is the lateral distribution value of the strip entrance thickness,

is the average length of the incoming material shape, L(x) is the lateral distribution value of the length of the incoming material shape, and Δu' is the lateral distribution function of the lateral displacement increment of the strip;

E、ν为工作辊的杨氏模量和泊松比；Then, in step (j), the balance unit outlet flatness value I under the current rolling pressure is calculated,

E and ν are Young’s modulus and Poisson’s ratio of the working roll;

其中，i为带钢横向条元数，I_i为带钢横向各条元板形分布值，α、β、γ为加权系数，此处取α＝0.4、β＝0.3、γ＝0.3，ψ为当前工况下的打滑因子，

其中工作辊压扁半径

Δh为压下量，R为工作辊半径，E、ν为工作辊的杨氏模量和泊松比；Then, in step (k), construct the objective function F(X) by

Among them, i is the number of transverse strips of the strip, I _i is the plate shape distribution value of each transverse strip of the strip, α, β, γ are weighting coefficients, where α = 0.4, β = 0.3, γ = 0.3, ψ is the slip factor under the current working condition,

The flattening radius of the working roll

Δh is the reduction, R is the radius of the working roll, E and ν are the Young's modulus and Poisson's ratio of the working roll;

Then, in step (l), the extreme value, i.e., the minimum value, of the objective function F(X) is obtained. If the result converges, the process immediately proceeds to step (m);

时的前后张力设定值和延伸率设定值。Then, in step (m), during the optimization process, when the following relationship exists between a certain function value F(X _i ) and the next function value F(X _i+1 ) calculated, the optimization can be stopped to obtain the optimal solution, that is, satisfying

The front and rear tension setting values and elongation setting values.

Finally, in step (n), the front and rear tension setting values and elongation setting values that meet the conditions are output, the front tension optimization value initial value = 36.5kN, the rear tension optimization value = 37.5kN, the elongation optimization value = 1.2%, and the optimization process ends.

Embodiment 2:

最大负弯辊力与

机架工作辊上机粗糙度Ra₁＝2.5μm、机架工作辊轧制公里数L＝0km、机架轧制力允许最大值P_max＝8000kN、出口板面粗糙度轧辊复印部分中机架带材的入口厚度影响线性系数与非线性系数分别为α_h＝6.556,α′_h＝1.444、机架出口板面粗糙度遗传部分中机架带材的入口厚度影响系数β_h＝6.556、机架出口板面粗糙度遗传部分与复印部分中末机架带材的材质影响系数α_k＝2.27,β_k＝－4、机架出口板面粗糙度遗传部分与轧辊复印部分中延伸率影响系数α_ε＝-127.3,β_ε＝400、机组设备特性影响参数η₁＝0.48,η₂＝0.377，带材的屈服极限σ_s＝500Mpa。；(a) Collect the equipment characteristic parameters of the single-stand skin-pass unit, mainly including: the working roll diameter D of the stand, the original roll profile distribution value of the working roll and the support roll ΔD _wi = 0, ΔD _bi = 0, the roll body length of the working roll and the support roll L ₁ = 1850mm, L ₂ = 1850mm, the cylinder distance of the working roll bending roll l ₁ = 2500mm, the center moment of the pressing screw l ₂ = 2500mm, the maximum positive roll bending force allowed for the working roll bending roll

Maximum negative bending roll force and

The machine roughness of the working roll of the stand is Ra ₁ = 2.5μm, the rolling mileage of the working roll of the stand is L = 0km, the maximum allowable rolling force of the stand is P _max = 8000kN, the linear coefficient and nonlinear coefficient of the entrance thickness of the stand strip in the roller copy part of the export plate surface roughness are α _h = 6.556, α′ _h = 1.444, the entrance thickness influence coefficient of the stand strip in the genetic part of the export plate surface roughness of the stand is β _h = 6.556, the material influence coefficient of the last stand strip in the genetic part and copy part of the export plate surface roughness of the stand is α _k = 2.27, β _k = -4, the elongation influence coefficient in the genetic part of the export plate surface roughness of the stand and the roller copy part is α _ε = -127.3, β _ε = 400, the unit equipment characteristic influencing parameters η ₁ = 0.48, η ₂ = 0.377, and the yield limit of the strip is σ _s = 500Mpa. ;

Subsequently, in step (b), key strip rolling process parameters for comprehensively setting metal model parameters are collected, mainly including: lateral distribution value of incoming strip thickness _Hi , _Hi = {0.368, 0.368, 0.368, 0.369, 0.369, 0.369, 0.369, 0.369, 0.370, 0.370, 0.370, 0.370, 0.369, 0.369, 0.369, 0.369, 0.369, 0.369, 0.368, 0.368, 0.368}, unit: mm; strip elongation ε = 1.28%, rolling speed V = 4 m/s, strip front and rear tensions _T0 = 37 kN, _T1 = 38 kN, strip outlet thickness _h1 =0.34mm, working roll diameter D = 430mm, strip width B = 1500mm;

Then, in step (c), process characteristic parameters are collected, mainly including: the maximum allowable plate shape SHAPE*; the maximum and minimum values of elongation ε _max =1.5%, ε _min =1.0%;

Then, in step (d), the bending roll force S is set to the base state.

Then, in step (e), the initial value of the front tension T ₀₁ =36.5 kN, the initial value of the rear tension T ₀₀ =37.5 kN, and the setting value of the elongation ε =1.25% are defined;

Then, in step (f), the actual value of the elongation under the current working condition is calculated as ε ^* =1.241%;

若偏差绝对值小于延伸率设定值的1％，则立即进入步骤(h)；Then, in step (g), the deviation between the actual value of elongation ε ^* and the set value of elongation ε under the current working condition is calculated.

If the absolute value of the deviation is less than 1% of the set value of the elongation, immediately proceed to step (h);

L为轧制变形区中轧辊与带材接触弧长度，

B为带材宽度，a₀、a₁为平整钢种与工况影响系数，σ_p为当量变形抗力，σ_p＝k₃·(σ_s+a′lg1000′e)-(k₁·T₁+k₂·T₀)，D为工作辊直径，ε为带材延伸率，μ为摩擦系数，h₀为带材入口厚度，e为变形速率，k₁、k₂为前后张力加权系数，k₃为变形抗力影响系数，σ_s为带材屈服强度，a为应变速率系数；Then, in step (h), the rolling pressure P under the current working condition is calculated, P = f·L; where f is the unit rolling force,

L is the contact arc length between the roller and the strip in the rolling deformation zone,

B is the strip width, a ₀ and a ₁ are the influence coefficients of flat steel grade and working conditions, σ _p is the equivalent deformation resistance, σ _p =k ₃ ·(σ _s +a′lg1000′e)-(k ₁ ·T ₁ +k ₂ ·T ₀ ), D is the working roll diameter, ε is the strip elongation, μ is the friction coefficient, h ₀ is the strip entrance thickness, e is the deformation rate, k ₁ and k ₂ are the weighted coefficients of the front and rear tensions, k ₃ is the influence coefficient of the deformation resistance, σ _s is the strip yield strength, and a is the strain rate coefficient;

其中，σ₁(x)为出口带材横向各点单位张力，σ₁为出口侧总张力，B为带材宽度，

为带材出口平均厚度，h(x)为带材出口厚度横向分布值，

为带材入口平均厚度，H(x)为带材入口厚度横向分布值，

为表示来料板形的长度平均值，L(x)为表示来料板形的长度横向分布值，Δu'为带材横向位移增量横向分布函数；Then, in step (i), the front tension transverse distribution of the finished strip is calculated under the conditions of the incoming material. The front tension transverse distribution can be expressed as:

Among them, σ ₁ (x) is the unit tension at each point in the transverse direction of the outlet strip, σ ₁ is the total tension on the outlet side, B is the strip width,

is the average thickness of the strip at the exit, h(x) is the transverse distribution value of the strip thickness at the exit,

is the average thickness of the strip at the entrance, H(x) is the lateral distribution value of the strip entrance thickness,

is the average length of the incoming material shape, L(x) is the lateral distribution value of the length of the incoming material shape, and Δu' is the lateral distribution function of the lateral displacement increment of the strip;

E、ν为工作辊的杨氏模量和泊松比；Then, in step (j), the balance unit outlet flatness value I under the current rolling pressure is calculated,

E and ν are Young’s modulus and Poisson’s ratio of the working roll;

其中，i为带钢横向条元数，I_i为带钢横向各条元板形分布值，α、β、γ为加权系数，此处取α＝0.4、β＝0.3、γ＝0.3，ψ为当前工况下的打滑因子，

其中工作辊压扁半径

Δh为压下量，R为工作辊半径，E、ν为工作辊的杨氏模量和泊松比；Then, in step (k), construct the objective function F(X) by

Among them, i is the number of transverse strips of the strip, I _i is the plate shape distribution value of each transverse strip of the strip, α, β, γ are weighting coefficients, where α = 0.4, β = 0.3, γ = 0.3, ψ is the slip factor under the current working condition,

The flattening radius of the working roll

Δh is the reduction, R is the radius of the working roll, E and ν are the Young's modulus and Poisson's ratio of the working roll;

Then, in step (1), the extreme value, i.e., the minimum value, of the objective function F(X) is obtained. If the result does not converge, the process returns to step (e);

Then, in step (e), the initial value of the front tension T ₀₁ =37.5 kN, the initial value of the rear tension T ₀₀ =38.9 kN, and the setting value of the elongation ε =1.25% are defined;

Then, in step (f), the actual value of the elongation under the current working condition is calculated as ε ^* =1.24%;

若偏差绝对值小于延伸率设定值的1％，则立即进入步骤(h)；Then, in step (g), the deviation between the actual value of elongation ε ^* and the set value of elongation ε under the current working condition is calculated.

If the absolute value of the deviation is less than 1% of the set value of the elongation, immediately proceed to step (h);

L为轧制变形区中轧辊与带材接触弧长度，

B为带材宽度，a₀、a₁为平整钢种与工况影响系数，σ_p为当量变形抗力，σ_p＝k₃·(σ_s+a′lg1000′e)-(k₁·T₁+k₂·T₀)，D为工作辊直径，ε为带材延伸率，μ为摩擦系数，h₀为带材入口厚度，e为变形速率，k₁、k₂为前后张力加权系数，k₃为变形抗力影响系数，σ_s为带材屈服强度，a为应变速率系数；Then, in step (h), the rolling pressure P under the current working condition is calculated, P = f·L; where f is the unit rolling force,

L is the contact arc length between the roller and the strip in the rolling deformation zone,

B is the strip width, a ₀ and a ₁ are the influence coefficients of flat steel grade and working conditions, σ _p is the equivalent deformation resistance, σ _p =k ₃ ·(σ _s +a′lg1000′e)-(k ₁ ·T ₁ +k ₂ ·T ₀ ), D is the working roll diameter, ε is the strip elongation, μ is the friction coefficient, h ₀ is the strip entrance thickness, e is the deformation rate, k ₁ and k ₂ are the weighted coefficients of the front and rear tensions, k ₃ is the influence coefficient of the deformation resistance, σ _s is the strip yield strength, and a is the strain rate coefficient;

其中，σ₁(x)为出口带材横向各点单位张力，σ₁为出口侧总张力，B为带材宽度，

为带材出口平均厚度，h(x)为带材出口厚度横向分布值，

为带材入口平均厚度，H(x)为带材入口厚度横向分布值，L为表示来料板形的长度平均值，L(x)为表示来料板形的长度横向分布值，Δu'为带材横向位移增量横向分布函数；Then, in step (i), the front tension transverse distribution of the finished strip is calculated under the conditions of the incoming material. The front tension transverse distribution can be expressed as:

Among them, σ ₁ (x) is the unit tension at each point in the transverse direction of the outlet strip, σ ₁ is the total tension on the outlet side, B is the strip width,

is the average thickness of the strip at the exit, h(x) is the transverse distribution value of the strip thickness at the exit,

is the average thickness of the strip at the entrance, H(x) is the transverse distribution value of the strip thickness at the entrance, L is the average length of the incoming material shape, L(x) is the transverse distribution value of the length of the incoming material shape, Δu' is the transverse distribution function of the strip transverse displacement increment;

E、ν为工作辊的杨氏模量和泊松比；Then, in step (j), the balance unit outlet flatness value I under the current rolling pressure is calculated,

E and ν are Young’s modulus and Poisson’s ratio of the working roll;

其中，i为带钢横向条元数，I_i为带钢横向各条元板形分布值，α、β、γ为加权系数，此处取α＝0.4、β＝0.3、γ＝0.3，ψ为当前工况下的打滑因子，

其中工作辊压扁半径

Δh为压下量，R为工作辊半径，E、ν为工作辊的杨氏模量和泊松比；Then, in step (k), construct the objective function F(X) by

Among them, i is the number of transverse strips of the strip, I _i is the plate shape distribution value of each transverse strip of the strip, α, β, γ are weighting coefficients, where α = 0.4, β = 0.3, γ = 0.3, ψ is the slip factor under the current working condition,

The flattening radius of the working roll

Δh is the reduction, R is the radius of the working roll, E and ν are the Young's modulus and Poisson's ratio of the working roll;

Then, in step (l), the extreme value, i.e., the minimum value, of the objective function F(X) is obtained, and when the result converges, the process proceeds to step (m);

时的前后张力设定值和延伸率设定值。Then, in step (m), during the optimization process, when the following relationship exists between a certain function value F(X _i ) and the next function value F(X _i+1 ) calculated, the optimization can be stopped to obtain the optimal solution, that is, satisfying

The front and rear tension setting values and elongation setting values.

Finally, in step (n), the front and rear tension setting values and elongation setting values that meet the conditions are output, the front tension optimization value initial value = 37.5kN, the rear tension optimization value = 38.9kN, the elongation optimization value = 1.24%, and the optimization process ends.

The present invention summarizes the production parameters of the leveling unit and comprehensively considers various factors to calculate the optimal front and rear tension distribution state of the unit. Compared with the conventional manual adjustment and plate shape feedback adjustment methods, the tension calculation and setting methods are closer to reality, more in line with the needs of on-site production, and can further improve the plate shape. The important innovation of the present invention is that it fully considers the equipment and process characteristics of the single-frame leveling unit, takes the export strip shape and slip factor as the objective function, and controls the actual elongation and the set elongation within a certain range as constraints. By setting the initial front and rear tensions and elongation, multiple iterations are performed to obtain production parameters that meet the requirements of plate shape control and rolling stability, while meeting the requirements of the two important indicators, which has important guiding significance for on-site production.

Claims (2)

1. A method for optimizing tension and elongation of a single-frame leveling unit, characterized by comprising the following steps: (a) Collect the equipment characteristic parameters of a single-frame leveling machine group; (b) collecting the key strip rolling process parameters for which the metal model parameters are to be comprehensively set, mainly including: the lateral distribution value of the incoming strip thickness _Hi , the elongation ε of the strip, the rolling speed V, the front and rear tensions _T0 and _T1 of the strip, the exit thickness _h1 of the strip, the working roll diameter D, the strip width B and the yield limit _σs of the strip; (c) Collecting process characteristic parameters, mainly including: the maximum allowable plate shape SHAPE*; the maximum and minimum elongation values ε _max , ε _min ; (d) setting the bending roll force to the base state; (e) defining the initial value of the front tension T ₀₁ , the initial value of the rear tension T ₀₀ , and the setting value ε of the elongation; (f) Calculate the actual value of elongation ε ^* under the current working condition; (g) Calculate the deviation between the actual elongation value ε ^* and the set elongation value ε under the current working conditions

If the absolute value of the deviation is less than 1% of the set value of the elongation, the process immediately proceeds to step (h); otherwise, the process returns to step (e) to adjust the set value of the elongation; (h) Calculate the rolling pressure P under the current working condition, P = f·L; where f is the unit rolling force,

L is the contact arc length between the roller and the strip in the rolling deformation zone,

B is the strip width, a ₀ and a ₁ are the influence coefficients of flat steel grade and working conditions, σ _p is the equivalent deformation resistance, σ _p =k ₃ ·(σ _s +a·lg1000·e)-(k ₁ ·T ₁ +k ₂ ·T ₀ ), D is the working roll diameter, ε is the strip elongation, μ is the friction coefficient, h ₀ is the strip entrance thickness, e is the deformation rate, k ₁ and k ₂ are the weighted coefficients of the front and rear tensions, k ₃ is the influence coefficient of the deformation resistance, σ _s is the strip yield strength, and a is the strain rate coefficient; (i) Calculate the lateral distribution of the front tension of the finished strip under the condition of certain incoming materials; the lateral distribution of the front tension can be expressed as:

Among them, σ ₁ (x) is the unit tension at each point in the transverse direction of the outlet strip, σ ₁ is the total tension on the outlet side, B is the strip width,

is the average thickness of the strip at the exit, h(x) is the transverse distribution value of the strip thickness at the exit,

is the average thickness of the strip at the entrance, H(x) is the lateral distribution value of the strip entrance thickness,

is the average length of the incoming material shape, L(x) is the lateral distribution value of the length of the incoming material shape, and Δu' is the lateral distribution function of the lateral displacement increment of the strip; (j) Calculate the outlet flatness value I of the balanced unit under the current rolling pressure,

E and ν are Young’s modulus and Poisson’s ratio of the working roll; (k) Construct the objective function F(X), let

Among them, i is the number of transverse strips of the strip, I _i is the plate shape distribution value of each transverse strip of the strip, α, β, γ are weighting coefficients, where α = 0.4, β = 0.3, γ = 0.3, ψ is the slip factor under the current working condition,

The flattening radius of the working roll

Δh is the reduction, R is the radius of the working roll, E and ν are the Young's modulus and Poisson's ratio of the working roll; (l) finding the extreme value, i.e., the minimum value, of the objective function F(X); if the result converges, immediately proceeding to step (m); otherwise, returning to step (e) to modify the initial setting values of the front and rear tensions; (m) During the optimization process, when the following relationship exists between a function value F(X _i ) and the next function value F(X _i+1 ) calculated, the optimization can be stopped to obtain the optimal solution, that is, satisfying

The front and rear tension setting values and elongation setting values; (n) Output the above-mentioned front and rear tension setting values and elongation setting values that meet the conditions, and the optimization process ends. 2. A method for optimizing the tension and elongation of a single-stand leveling unit according to claim 1, characterized in that: in the step (a), the equipment characteristic parameters of the single-stand leveling unit include: the diameter D of the working roll of the frame, the original roll profile distribution values ΔD _wi and ΔD _bi of the working roll and the support roll, the roll body lengths L ₁ and L ₂ of the working roll and the support roll, the cylinder distance of the working roll bending roll l ₂ , the center moment of the pressing screw l ₁ , the maximum positive and negative bending roll forces allowed for the working roll bending roll

and

The machine roughness Ra ₁ of the stand working roll, the rolling mileage L of the stand working roll, the maximum allowable rolling force P _max of the stand, the linear coefficient and nonlinear coefficient of the entrance thickness of the stand strip in the roller copy part of the exit plate surface roughness are α _h , α' _h , the entrance thickness influence coefficient of the stand strip in the genetic part of the stand exit plate surface roughness β _h , the material influence coefficient of the last stand strip in the genetic part and copy part of the stand exit plate surface roughness α _k , β _k , the elongation influence coefficient α _ε , β _ε in the genetic part of the stand exit plate surface roughness and the roller copy part and the unit equipment characteristic influence parameters η ₁ ,η ₂ .

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