CN101927268B - Method for controlling thickness of tandem cold-rolled striped steel - Google Patents

Abstract

The invention discloses a method for controlling the deformation resistance of the tandem cold-rolled striped steel. The method comprises the following steps: 1) calculating the actual value of the deformation resistance in the tandem cold-rolling technology; 2) calculating the parameters of the deformation resistance model according to the actual value of the deformation resistance; and setting the parameters of the tandem cold-rolling technology according to the calculated parameters of the deformation resistance model so as to control the thickness of tandem cold-rolled striped steel. In the method of the invention, the regressive calculation of the deformation resistance is performed by actually measuring the parameters such as the thickness, tension and rolling force of the striped steel to calculate the parameters of the deformation resistance model. The parameters are used by the model technical personnel on the spot to set the parameters, thus increasing the accuracy of the parameters of the model and increasing and controlling the accuracy of the set parameters such as rolling force and roll gap which are related to the thickness of the striped steel.

Description

Method for controlling thickness of tandem cold-rolled striped steel

Technical field

The present invention relates to the stainless steel continuous cold rolling process field in metallurgical automation, relate in particular to a kind of method for controlling thickness of tandem cold-rolled striped steel.

Background technology

In stainless steel Continuous Cold Rolled Strip production process, resistance of deformation is important material parameter and controls parameter, because resistance of deformation is the most basic influence factor of roll-force, therefore the computational accuracy of resistance of deformation has directly determined the computational accuracy of roll-force, and then has affected the thickness control accuracy with steel.

In order to improve the computational accuracy of resistance of deformation, need to select to reflect the deformation resistance model of stainless steel deformation characteristics, at this, adopt the regression model of resistance of deformation, the quality that wherein model parameter is set directly affects the calculating of resistance of deformation.Because the resistance of deformation of material in the operation of rolling is subject to the impact of many factors, and deformation resistance model itself can not be considered these factors one by one.

Because the resistance of deformation with steel in the operation of rolling cannot detect online, the recurrence of the deformation resistance in the operation of rolling is calculated and is utilized actual roll-force, tension force and thickness equivalent calculation to process, and the actual value substitution roll-force equations such as roll-force, tension force and thickness are calculated to deformation resistance value.Obviously, the roll-force equation of relevant variable deformation resistance kp is a nonlinear equation.

Due to the defect of deformation resistance model in prior art itself, and in prior art, the roll-force equation of relevant variable deformation resistance is a nonlinear equation.The defect that originally deformation resistance model parameter is only set according to experience or similar steel grade, along with the continuous appearance of new steel grade, adopts the model parameter of empirical value can not adapt to new steel grade, is unfavorable for that the accurate setting of rolling parameter is calculated.And in prior art method for controlling thickness of tandem cold-rolled striped steel owing to adopting the nonlinear equation of deformation resistance model, not only arithmetic speed is slow, and the many factors that affects resistance of deformation is not taken into account in computational process, therefore reduced the precision of calculating, thereby reduced coil of strip roll-force precision, affected the control accuracy of belt steel thickness.

Summary of the invention

Technical problem to be solved by this invention is to provide a kind of method for controlling thickness of tandem cold-rolled striped steel, thereby the parameter of setting continuous cold rolling process by calculating deformation resistance model parameter is controlled Continuous Cold Rolled Strip thickness more accurately.

For solving the problems of the technologies described above, the technical scheme of method for controlling thickness of tandem cold-rolled striped steel of the present invention is to comprise the following steps:

1) calculate resistance of deformation actual value in continuous cold rolling process;

2) according to resistance of deformation essence value, calculate deformation resistance model parameter;

3) thus according to the parameter of the deformation resistance model setting parameter continuous cold rolling process that calculates, control Continuous Cold Rolled Strip rolling force setup value precision, thereby the accurate thickness of controlling with steel.

As a further improvement on the present invention, step 1), adopt actual measurement belt steel thickness, tension force and roll-force to calculate resistance of deformation.

As another kind of further improvement of the present invention, be, by step 3) result substitution step 1) in repeating step 1) to step 3), until belt steel thickness precision actual value meets default requirement.

The present invention surveys the parameter values such as belt steel thickness, tension force and roll-force resistance of deformation is returned to calculating by employing, and then calculate deformation resistance model parameter for on-the-spot modelling technique personnel's reference, be conducive to more accurately deformation resistance model parameter be set when debugging and model maintenance, thus the accuracy of raising steel plate thickness.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the present invention is further detailed explanation:

Figure is schematic flow sheet of the present invention.

The specific embodiment

As shown in Figure 1, method for controlling thickness of tandem cold-rolled striped steel of the present invention comprises three steps: be first to calculate resistance of deformation actual value in continuous cold rolling process, then according to resistance of deformation essence value, calculate deformation resistance model parameter, thus the last parameter according to the deformation resistance model setting parameter continuous cold rolling process calculating control Continuous Cold Rolled Strip thickness.And, in specific embodiment, can increase a step: by step 3) result substitution step 1) in repeating step 1) to step 3), until belt steel rolling power setting value precision meets the demands, the method that can calculate by recurrence like this makes the more and more approaching of belt steel rolling power and requirement.

In the present invention, calculate resistance of deformation actual value in continuous cold rolling process and adopt recurrence computational methods, by roll-force P, strip width b, impedance, tension force influence coefficient k, stress state coefficient Dp, flattening radius R ', inlet thickness H, exit thickness h, the backward pull tb of unit, resistance of deformation actual value kp in the parameter changes persuing shape operations of rolling such as the forward pull tf of unit.

In calculating the distortion operation of rolling, resistance of deformation actual value kp comprises the following steps:

1. according to rolling force model formula, calculate

Therefore roll-force formula is known, in computational process, because actual roll-force is known, can calculate flattening radius, then according to actual (real) thickness with enter, export tension force, the model calculation just can obtain unknown kpk so, $M1=\mathrm{kp}\·k=\frac{P}{b\·\mathrm{Dp}\·\sqrt{R^{\′}(H-h)}}$

Arrange:

$M1=1.15\mathrm{kp}-0.15*\frac{{(\mathrm{kp}-\mathrm{tb})}^2}{\mathrm{kp}-\mathrm{tf}}-1.05\mathrm{tb}-0.1\mathrm{tf}$

2. make M2=-1.05tb-0.1tf-M1

Omit given data item, arrange:

$M2=-(\mathrm{kp}+\mathrm{tf})+\frac{0.15{(\mathrm{tb}-\mathrm{tf})}^2}{\mathrm{kp}-\mathrm{tf}}-0.3\mathrm{tb}+1.15\mathrm{tf}$

3. make M3=M2+0.3tb-1.15tf

So still can omit given data item, and pay close attention to deformation resistance kp.

Arrange

$M3=-(\mathrm{kp}+\mathrm{tf})+\frac{0.15{(\mathrm{tb}-\mathrm{tf})}^2}{\mathrm{kp}-\mathrm{tf}}$

4. establish $X=(\mathrm{kp}-\mathrm{tf})+\frac{0.15{(\mathrm{tb}-\mathrm{tf})}^2}{\mathrm{kp}-\mathrm{tf}}$

So, $\mathrm{kp}=\frac{X-M3}{2}.$

X is converted to the form relevant with M3.

$\begin{array}{c}{X}^2={[(\mathrm{kp}-\mathrm{tf})+\frac{0.15{(\mathrm{tb}-\mathrm{tf})}^2}{\mathrm{kp}-\mathrm{tf}}]}^2\\ ={M3}^2+4[\mathrm{kp}*\frac{0.15{(\mathrm{tb}-\mathrm{tf})}^2}{\mathrm{kp}-\mathrm{tf}}-\mathrm{kp}*\mathrm{tf}]\end{array}$

Data in 4 times are converted into the form relevant with M1 \ M2 \ M3.

$\begin{array}{c}M4=\mathrm{kp}*\frac{0.15{(\mathrm{tb}-\mathrm{tf})}^2}{\mathrm{kp}-\mathrm{tf}}-\mathrm{kp}*\mathrm{tf}\\ =(-1.15\mathrm{kp}+\frac{0.15{(\mathrm{kp}-\mathrm{tb})}^2}{\mathrm{kp}-\mathrm{tf}})\mathrm{tf}+{0.15\mathrm{tb}}^2\\ =M2\·\mathrm{tf}+{0.15\mathrm{tb}}^2\end{array}$

5. at this, M1 \ M2 \ M3 \ M4 can adopt measured data to calculate.

Hence one can see that, $\mathrm{kp}=\frac{\sqrt{{M3}^2+4*(M2\·\mathrm{tf}+{0.15\mathrm{tb}}^2)}-M3}{2},$ Therefore the actual value kp of resistance of deformation can by understanding nonlinear equation, direct solution obtain, and uses online thereby be conducive to computer system.In above formula, wherein P is roll-force, b is strip width, and kp is the deformation resistance in the operation of rolling, and k is tension force influence coefficient, Dp is stress state coefficient, adopt HILL formula, R ' flattens radius, and H is inlet thickness, h is exit thickness, tbShi unit's backward pull, tfShi unit's forward pull, M1 \ M2 \ M3 \ M4 is intermediate computations variable.

Can be according in cold-rolled process in calculating deformation resistance model parameter, the value of material deformation drag is divided into different situations and calculates.

In cold continuous rolling process, when the resistance of deformation of material is greater than 85, the resistance of deformation of material is along with the impact of velocity variations is very little, therefore static deformation drag equals resistance of deformation actual value; When the resistance of deformation of material is less than 85, the impact that the resistance of deformation of material is rolled speed clearly.

Statistical deformation resistance model:

$\mathrm{skp}=l{(\ln \frac{1}{1-r_t}+m)}^n$

Wherein skp is static deformation drag; r _tfor total drafts.

According to the size of material deformation drag, be divided into two kinds of situations:

1,, when kp >=85, resistance of deformation actual value kp equals static deformation drag skp

Deformation resistance model parameter

Wherein, l _ibe the deformation resistance model parameter of i frame, r _ibe the actual average reduction ratio of i frame, n _set, m _setit is the deformation resistance model parameter of rule of thumb setting.

2,, when kp < 85, adopt cycle calculations static deformation drag skp given below

The first step: initial value sk=15 is set;

Second step: calculated factor

α determines the susceptibility of STRESS VARIATION and represents the reliability of stress rate;

The 3rd step: calculate static deformation drag

ε is the stress rate that adopts actual reduction ratio and speed to calculate;

The 4th step: if | sk-skp| < 1.0, calculates and finishes; Otherwise, return to first step sk=sk+2 (sk < 85.0).

After static deformation drag skp has calculated, calculate deformation resistance model parameter

l wherein _i, r _i, n _set, m _setimplication the same.

3, calculate deformation resistance model parameter 1, n

N wherein _set, m _set: the deformation resistance model parameter of rule of thumb setting;

L, m, n: the deformation resistance model parameter calculating according to the data regression of actual measurement.

Deformation resistance model parameter is material important in process control and controls parameter, the parameter l of calculating by recurrence, n is as statistical parameter, the foundation that provide important model parameter to revise can to cold rolling on-the-spot model maintenance personnel, and then the rolling parameters such as roll-force are accurately set to calculating.

The present invention returns calculating by parameters such as actual measurement belt steel thickness, tension force, roll-forces to resistance of deformation, today calculate deformation resistance model parameter and carry out setting parameter for on-the-spot modelling technique personnel, increase the accuracy of model parameter, thereby improve the accuracy that belt steel rolling force parameter is controlled.

Claims (1)

1. a method for controlling thickness of tandem cold-rolled striped steel, is characterized in that, comprises the following steps:

1) adopt actual measurement belt steel thickness, tension force and roll-force to calculate resistance of deformation actual value in continuous cold rolling process; Calculation procedure and the formula of resistance of deformation actual value kp are as follows:

a. $M1=\mathrm{kp}\&CenterDot;k=\frac{P}{b\&CenterDot;\mathrm{Dp}\&CenterDot;\sqrt{R^{\&prime;}(H-h)}}$

$M1=1.15\mathrm{kp}-0.15*\frac{{(\mathrm{kp}-\mathrm{tb})}^2}{\mathrm{kp}-\mathrm{tf}}-1.05\mathrm{tb}-0.1\mathrm{tf},$ Wherein, kp is the resistance of deformation actual value in the operation of rolling, and P is roll-force, and b is strip width, k is tension force influence coefficient, and Dp is stress state coefficient, and R ' flattens radius, and H is inlet thickness, h is exit thickness, tbShi unit's backward pull, and tfShi unit's forward pull, M1 is intermediate computations variable;

b.M2=-1.05tb-0.1tf-M1， $M2=-(\mathrm{kp}+\mathrm{tf})+\frac{0.15{(\mathrm{tb}-\mathrm{tf})}^2}{\mathrm{kp}-\mathrm{tf}}-0.3\mathrm{tb}+1.15\mathrm{tf},$ Wherein, M2 is intermediate computations variable;

C. make M3=M2+0.3tb-1.15tf, $M3=-(\mathrm{kp}+\mathrm{tf})+\frac{0.15{(\mathrm{tb}-\mathrm{tf})}^2}{\mathrm{kp}-\mathrm{tf}},$ Wherein, M3 is intermediate computations variable;

D. order $X=(\mathrm{kp}-\mathrm{tf})+\frac{0.15{(\mathrm{tb}-\mathrm{tf})}^2}{\mathrm{kp}-\mathrm{tf}},$ $X^2={M3}^2+4[\mathrm{kp}*\frac{0.15{(\mathrm{tb}-\mathrm{tf})}^2}{\mathrm{kp}-\mathrm{tf}}-\mathrm{kp}*\mathrm{tf}],$

$M4=\mathrm{kp}*\frac{0.15{(\mathrm{tb}-\mathrm{tf})}^2}{\mathrm{kp}-\mathrm{tf}}-\mathrm{kp}*\mathrm{tf},$ M4=M2tf+0.15tb ², wherein, X and M4 are intermediate computations variable;

E. according to formula $\mathrm{kp}=\frac{\sqrt{{M3}^2+4*(M2\&CenterDot;\mathrm{tf}+{0.15\mathrm{tb}}^2)}-M3}{2}$ Calculate the resistance of deformation actual value kp in the operation of rolling;

2) according to resistance of deformation calculated with actual values deformation resistance model parameter; Calculation procedure and the formula of deformation resistance model parameter are as follows:

When kp>=85, resistance of deformation actual value kp equals static deformation drag skp, deformation resistance model parameter

wherein, l _ibe the deformation resistance model parameter of i frame, r _ibe the actual average reduction ratio of i frame, n _set, m _setit is the deformation resistance model parameter of rule of thumb setting;

When kp < 85, calculate in two steps deformation resistance model parameter:

The first step, calculates static deformation drag skp;

Second step, calculates deformation resistance model parameter;

Wherein, first step calculating static deformation drag skp is divided into following steps:

I: initial value sk=15 is set;

II: calculated factor

α determines the susceptibility of STRESS VARIATION and represents the reliability of stress rate;

III: calculate static deformation drag

ε is the stress rate that adopts actual reduction ratio and speed to calculate;

IV: if | sk-skp| < 1.0, calculates and finishes; Otherwise, return to first step sk=sk+2 (sk < 85.0);

3) thus according to the parameter of the deformation resistance model setting parameter continuous cold rolling process that calculates, control the setting accuracy of Continuous Cold Rolled Strip roll-force parameter, thereby the accurate thickness of controlling with steel.

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