CN101992218A - Method for correcting cold-rolled strip steel shape control target value - Google Patents

Abstract

The invention discloses a method for correcting a cold-rolled strip steel shape control target value. In the method, a basic shape target value curve model is made according to the requirement of subsequent processes on the convexity of the strip steel and strip instability model criterion; and four compensating curves of coiled shape, recoiling machine mounted geometric error, strip steel transverse temperature difference and strip steel side reduction and two manually adjusted shape additional curves are formed according to adverse effects of temperature, coiled shape, equipment mounting error and the like on shape measurement. An actual shape measurement point is interpolated into a plurality of characteristic points along a width direction, and the data processing process is simplified. When the convexity of the strip steel is effectively controlled, the shape control effect is guaranteed, and the requirements of the subsequent processes on the convexity of the strip steel and the shape are met. After the method is applied to a cold-rolled shape control system, the finished cold-rolled strip steel product has higher shape control accuracy, and completely meets the high-accuracy shape control requirement.

Description

The modification method of cold-rolled strip steel shape control desired value

Technical field

The invention belongs to the cold-strip steel field, relate in particular to a kind of modification method that is applicable to cold-rolled strip steel shape control desired value.

Background technology

In recent years, along with the continuous expansion of the cold-strip steel scope of application, the user is also more and more higher to the quality requirement of strip profile and flatness, and therefore the plate shape control with steel has become emphasis and the difficult point problem of competitively studying countries in the world.Plate shape desired value curve is that plat control system is regulated the theoretically perfect tray shape curve that belt plate shape should reach, and also is the plate shape in kind that the producer expects.In the production process, the plate shape curve controlled of reality to the desired value curve, is eliminated difference between the two as far as possible.Its effect mainly is that compensating plate shape measure error, compensation change behind the online plate shape off-line, control panel convexity and satisfy rolling and subsequent handling to the specific (special) requirements of plate shape etc. effectively.The plate-shape standard curve model is one of basic model of plate shape control, is the object module of plate shape control.How by in the actual cold rolling production of theoretical calculations incorporated to the requirement of plate shape control, set up concrete flatness object curve model, and use it in the plat control system of milling train, realize that milling train is problem demanding prompt solution in the actual production to the high precision plates shape control of cold-strip steel.

Summary of the invention

Realized the closed-loop control of plate shape on the comfortable cold-rolling mill, just begun research about cold rolled sheet shape control desired value curve, and experienced that not produce the bent shape wave of wooden dipper with the band steel be plate shape target, the setting compensation by flatness object curve or eliminate non-plate shape signal in the plate profile instrument measured signal, consider the some developing stage such as requirement of follow-up unit to plate shape.Yet in the operation of rolling, because the influence of various factors, band steel longitudinal extension often is uneven on width, so that generation is poor along the uneven vertical internal stress of cross direction profiles.If this internal stress difference surpasses certain scope along the cross direction profiles degree of irregularity, will cause the buckling deformation of band steel, cause flatness defect.If can measure and the corresponding cross direction profiles of rolling back band steel longitudinal fiber relative length difference of actual tensile stress cross direction profiles by plate shape roller when rolling, then can control the final actual plate shape attitude of band steel.Yet practical situation is unsatisfactory because the influence of various factors and the specific (special) requirements of follow-up unit, roll the final actual plate shape of back band steel and when rolling online actual measurement plate shape certain difference is arranged.Therefore, when setting plate shape desired value curve, just need to balance out the unfavorable factor that influences plate shape measurement and control by the setting compensation curve.

In order to realize to effective control of strip profile and eliminate the error that some unfavorable factors cause plate shape measurement in the operation of rolling that this system uses the desired value of plate shape desired value correction model as the control of closed loop plate shape.In actual production, subsequent handling is very high to the requirement of strip profile and plate shape, and this just need also will guarantee to have good strip shape quality with steel when strip profile is effectively controlled.Plate shape control effect and plate shape measurement are closely related, the factor that influences plate shape measurement mainly contains: when (1) carries out plate shape measurement with plate shape roller by measuring the tension force cross direction profiles, because the error of mechanical system,, plate shape roller deflection deformation not parallel as coiling machine and plate shape roll axis etc. can cause the plate shape measurement error.(2) roll back band steel transverse temperature skewness, produce the temperature additional stress.(3), cause to produce when batching and batch additional stress because there is the transverse gage skewness in the band steel.Like this, how to realize effective control, eliminate the error that produces in the plate shape measurement simultaneously, and then reach the control of high-precision plate shape and just become an important techniques problem strip profile.

The present invention just is being based on above-mentioned consideration, it is reasonable that purpose aims to provide a kind of factor, calculate accurately, the method practicality, control effectively can be eliminated the plate shape measurement error, realizes the effective control to strip profile, and then the high precision plates shape of passing through the closed loop plat control system is controlled the modification method of the cold-rolled strip steel shape control desired value of raising product strip shape quality.

For this reason, the technical solution that the present invention taked is:

A kind of modification method of cold-rolled strip steel shape control desired value is set up basic plate shape desired value curve model according to subsequent handling to the requirement and the band unstability model criterion of strip profile; The adverse effect that plate shape measurement is caused at temperature, scroll and equipment alignment error in producing, calculate respectively to set up according to equipment ruuning situation and rolling technological parameter and batch shape compensated curve, coiling machine geometric error compensation curve, band steel transverse temperature difference compensated curve and strip edge portion attenuate compensated curve are installed, set the roller and the roller declination additive curve of manual adjustments plate shape, improve the flexibility of plate shape control; Simultaneously, be the several features point with actual plate shape measurement point broad ways interpolation, the reduced data processing procedure; And various compensated curves are added on the basic flatness object curve, thereby obtain to be used for the band steel shape control target value curve of closed-loop feed-back type plat control system.

In other words, in order to eliminate the adverse effect to plate shape measurement such as temperature in the production, scroll and equipment alignment error, four kinds of compensated curves and two kinds of manual adjustments plate shape additive curves have been worked out exactly according to equipment ruuning situation and rolling mill practice.When definite plate shape desired value setting curve, at first calculate the mean value of the compensation rate and the manual adjustments amount of each effective measurement point, then the compensation settings of each measurement point is deducted this mean value and obtain being with steel tensile stress departure, departure is added to can obtain flatness object curve on the elementary object plate shape curve.Simultaneously, be the several features point with actual plate shape measurement point broad ways interpolation, the reduced data processing procedure.And the target tensile stress at these characteristic point places is used for plate shape closed loop feedback control system as plate shape target deviation.Its concrete Consideration and computational methods are:

Step 1, the requirement and the band unstability model criterion of strip profile are worked out basic plate shape desired value curve model based on subsequent handling.

Basic flatness object curve is mainly set based on the control to strip crown.When reducing strip profile, roll back band steel generation wooden dipper song in order not cause, need be foundation to roll back band unstability discrimination model, can not reduce strip profile simply, must guarantee that plate shape is good.According to the cross direction profiles of residual stress, differentiate band whether unstability or plate shape good degree, thereby how decision further adjusts strip crown and plate shape.Band unstability discrimination model is a mechanics criterion, and mechanism is the result that the flexing unstability takes place along the plate width direction skewness rolling residual stress.

Roll back band unstability discrimination model and formulate, and carry out the calculating that the band unstability is differentiated based on the Post-buckling Theory of band steel.If unstability thinks that then plate shape is bad; If unstability does not think that then plate shape can be accepted, and is relatively good.When carrying out the calculating of the good criterion of plate shape, differentiate factor ξ with one and judge plate shape condition, that is:

In the formula: ξ differentiates the factor for band steel unstability.

The setting of basic flatness object curve is a foundation to roll back band unstability discrimination model, takes into full account the requirement to belt plate shape of supplied materials band convexity and subsequent handling.The form of basic flatness object curve is a second-degree parabola, calculates parabolical amplitude by process computer, and sends plate shape computer to.

The form of basic flatness object curve is:

${\mathrm{\σ}}_{\mathrm{base}}\left(x_i\right)=\frac{A_{\mathrm{base}}}{x_{\mathrm{os}}^2}\·x_i^2-{\stackrel{\‾}{\mathrm{\σ}}}_{\mathrm{base}}---\left(2\right)$

In the formula: σ _Base(x _i) be the setting value of each measuring section place band steel tensile stress deviation;

A _BaseFor process computer according to the band adjustment amount of plate crown and the amplitude of the basic flatness object curve that band unstability discrimination model calculates, symbol is relevant with the supplied materials pattern;

x _iFor being the coordinate of each measuring section of the origin of coordinates with band steel center, tape symbol, fore side be for negative, and transmission side is for just;

x _OsCoordinate for the effective measurement point of fore side strip edge portion;

σ _BaseBe average tensile stress.

Process computer calculates amplitude A _BaseThe time, according to different incoming band steel specifications,,, promptly differentiate under the situation of factor ξ＞1 guaranteeing that plate shape does not produce defective based on band unstability discrimination model, reduce strip profile as much as possible in former passages; Several passages in back are then focused on control panel shape, retainer belt steel ratio convexity unanimity.

Average tensile stress computing formula is:

${\stackrel{\‾}{\mathrm{\σ}}}_{\mathrm{base}}=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\frac{A_{\mathrm{base}}}{x_{\mathrm{os}}^2}\·x_i^2---\left(3\right)$

In the formula: n is that plate shape is effectively measured hop count.

The form of basic flatness object curve is a conic section, when each passage begins, after plate shape computer receives the amplitude of process computer transmission, judge at first whether the band steel produces sideslip, determine that according to the effective measurement point of strip edge portion of transmission side and fore side total effective measurement counts then, and calculate the tensile stress setting value of each effective measurement point piecemeal according to formula (2), finally form complete flatness object curve.As shown in Figure 1.

Secondly, from phase balance condition, in the strip width scope, basic flatness object curve also should satisfy following formula by the band internal stress:

$\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\mathrm{\σ}\left(x_i\right)=0---\left(4\right)$

Step 2, formulation scroll correction-compensation curve model.

The scroll correction is called the scroll compensation again.Because band steel transverse gage distributes and is positive protuberance shape, along with rolling carrying out, the coil of strip coil diameter increases gradually on the coiling machine, cause on the coiling machine coil of strip gabarit to be convex vertically or batch radius and do not wait vertically, this will cause being with steel when take-up along laterally producing speed difference, make band steel broad ways around volume the time have additional stress.The computing formula of batching additional stress is:

${\mathrm{\σ}}_{\mathrm{cshc}}\left(x_i\right)=\frac{A_{\mathrm{cshc}}}{x_{\mathrm{os}}^2}\·\frac{d-d_{\min }}{d_{\max }-d_{\min }}\·x_i^2---\left(5\right)$

In the formula: A _CshcBe the scroll correction factor, obtain according to the actual production technology Calculation by process computer;

D is current coiling machine coil diameter;

d _MinBe minimum coil diameter;

d _MaxBe maximum coil diameter.

Step 3, formulation coiling machine are installed geometric error correction-compensation curve model.

Because the restriction of equipment mounting condition coiling machine axis and the uneven situation of plate shape roll axis usually can occur, as shown in Figure 2.Owing to have uneven coiling tension in the coiling process, this will inevitably impact the plate shape measurement of band steel.

In order to eliminate this influence, in flatness object curve, increased coiling machine the geometric error compensation link has been installed, this error compensation is linear the correction, formulates according to skew direction and angle excursion between coiling machine and the plate shape roller, its computing formula is:

${\mathrm{\&sigma;}}_{\mathrm{geo}}\left(x_i\right)=x_i\&CenterDot;\frac{A_{\mathrm{<figure-callout\; id="2"\; label="geo"\; filenames="H2009100133604E00021.png,H2009100133604E00023.png"\; state="\{\{state\}\}">geo</figure-callout>}}}{2\&CenterDot;x_{\mathrm{os}}}\&CenterDot;E---\left(6\right)$

In the formula: A _GeoBe the linear compensation coefficient; E is an elastic modelling quantity.

A _GeoUnit be I, it is a plate shape value, relevant with skew direction and angle excursion between coiling machine and the plate shape roll axis, characterized owing to the deflection between coiling machine axis and the plate shape roll axis, the plate shape deviation size that produces between plate shape roller fore side that causes and the transmission side.When the coiling machine transmission side is lower than fore side in the horizontal direction, A _GeoValue is being for just, otherwise for bearing.

Step 4, setting band steel transverse temperature difference correction-compensation curve model.

In the operation of rolling, distortion there are differences the temperature of band steel on width, and it will cause that the band steel extends along uneven horizontal heat laterally occurring, and this is reflected as coiling tension along laterally producing uneven temperature additional stress.As not revising its influence, although in the operation of rolling, will be with the steel stress-deviation to adjust to zero, the band steel that still can not obtain to have good glacing flatness.This is because when band steel transverse temperature difference is big, finally actual plate shape is also inequality with rolling the back for the online actual measurement plate of plate shape roller shape, after rolling back band steel temperature difference disappearance, the edge is with the higher part of the laterally original temperature of steel owing to the influence of expanding with heat and contract with cold can produce retraction, controls effect thereby influence plate shape.When exist between horizontal 2 of the steel of band temperature difference t (℃) time, expand to simplify according to linear elasticity and calculate, then the shape wave that can obtain producing is:

$\frac{\mathrm{\&Delta;l}}{l}=\frac{\mathrm{\&Delta;t}\&CenterDot;\mathrm{\&alpha;}\&CenterDot;l}{l}=\mathrm{\&Delta;t}\&CenterDot;\mathrm{\&alpha;}---\left(7\right)$

In the formula: Δ l, l are respectively extension difference and the datum length on the band steel length direction;

α is band steel thermal coefficient of expansion.

Through behind several passages rolling, the band steel has produced bigger deflection, causes with steel the bigger temperature difference being arranged on width, will influence final plate shape control effect.In order to eliminate band steel transverse temperature difference, can adopt the method for design temperature compensated curve to rolling the influence of back plate shape.

By formula (7) in conjunction with Hooke's law as can be known temperature additional stress expression formula be:

Δσ _i(x)＝k·t(x) (8)

In the formula: Δ σ _i(x) be the uneven temperature additional stress;

K is a proportionality coefficient, gets 2.5;

T (x) is a temperature difference distribution function.

After using infrared radiation thermometer to survey out last each position temperature of frame outlet band steel, can determine its Temperature Distribution function by the curve match, as shown in Figure 3.Through the temperature difference distribution function after the Mathematical treatment be:

t(x)＝ax ⁴+bx ³+cx ²+dx+m (9)

In the formula: a, b, c, d, m are the coefficient of the temperature difference distribution function after the curve match;

X is a strip width direction coordinate.

Then being used to offset the additional stress curve of being with the steel transverse temperature difference to produce is:

${\mathrm{\&sigma;}}_i\left(x_i\right)=-2.5({\mathrm{ax}}_i^4+b{x}_i^3+c{x}_i^2+d{x}_i+m)---\left(10\right)$

Step 5, determine strip edge portion attenuate correction-compensation curve model.

The cross-sectional profiles shape of cold-strip steel, outside the flash trimming portion zone, the band steel section of zone line roughly has the feature of conic section.And meeting the near part place, and thickness reduces rapidly suddenly, forms edge thinning, and said edge drop in promptly producing is called for short the limit and falls.Edge thinning is the important cross section quality index of band steel, directly has influence on the size that damage is cut by limit portion, with lumber recovery confidential relation is arranged.In order to reduce edge thinning, formulated the edge thinning compensation scheme, according to the situation of edge thinning in producing, respectively select several measurement points to compensate at fore side and transmission side, fore side compensation computing formula is:

${\mathrm{\&sigma;}}_{\mathrm{os}\_\mathrm{edge}}\left(x_i\right)=\frac{A_{\mathrm{edge}}+A_{\mathrm{man}\_\mathrm{edge}}}{{(x_{\mathrm{os}}-x_{\mathrm{os}\_\mathrm{edge}})}^2}\&CenterDot;{(x_i-x_{\mathrm{os}\_\mathrm{edge}})}^2,(x_{\mathrm{os}}\&le;x_i\&le;x_{\mathrm{os}\_\mathrm{edge}})---\left(11\right)$

In the formula: A _EdgeBe the edge thinning penalty coefficient, determine, calculate, send to plate shape computer by process computer according to the strip edge portion attenuate situation that occurs in producing;

A _{Man_edge}Be the manual adjustments amount of edge thinning coefficient, this is generated by ramp function in order to tackle in the production edge thinning and constantly to change and setting, and through amplitude limiting processing;

x _{Os_edge}For lighting from first effective measurement of fore side, last has the measurement point coordinate of edge thinning compensation.

Then: the measurement point number that fore side carries out the edge thinning compensation is:

n _os＝|x _os-x _{os_edge}| (12)

The edge thinning compensation computing formula of transmission side is:

${\mathrm{\&sigma;}}_{\mathrm{ds}\_\mathrm{edge}}\left(x_i\right)=\frac{A_{\mathrm{edge}}+A_{\mathrm{man}\_\mathrm{edge}}}{{(x_{\mathrm{ds}}-x_{\mathrm{ds}\_\mathrm{edge}})}^2}\&CenterDot;{(x_i-x_{\mathrm{ds}\_\mathrm{edge}})}^2,(x_{\mathrm{ds}\_\mathrm{edge}}\&le;x_i\&le;x_{\mathrm{ds}})---\left(13\right)$

In the formula: x _{Ds_edge}For lighting from first effective measurement of transmission side, last has the measurement point coordinate of edge thinning compensation.

The measurement point number that transmission side carries out the edge thinning compensation is:

n _ds＝|x _ds-x _{ds_edge}| (14)

According to the edge thinning situation that occurs in rolling mill practice and the production, the general operation side is identical with the measurement point number of transmission side portion compensation, i.e. n _Os=n _Ds

Step 6, formulation roller and inclination manual adjustments additive curve model.

In order to obtain better plate shape control effect, and the flexibility that more adapts to actual production, except compensating the influence that various influence factors cause plate shape measurement, also the plate shape governor motion that has according to milling train has been formulated roller and roller declination manual adjustments additive curve respectively to the characteristic of plate shape control.Can be according to the plate shape problem that occurs in the actual production, by operative employee's online adjusting flatness object curve on picture.

A, roller manual adjustments additive curve

${\mathrm{\&sigma;}}_{\mathrm{bend}}\left(x_i\right)=\frac{A_{\mathrm{man}\_\mathrm{<figure-callout\; id="2"\; label="bend\; x\; os"\; filenames="H2009100133604E00021.png,H2009100133604E00023.png"\; state="\{\{state\}\}">bend</figure-callout>}}}{x_{\mathrm{os}}^{}}\&CenterDot;x_i^2---\left(15\right)$

In the formula: A _{Man_bend}Be roller manual adjustments coefficient, not carrying out the manual adjustments duration is 0, generate by ramp function during adjusting, and through amplitude limiting processing.

B, inclination manual adjustments additive curve

${\mathrm{\&sigma;}}_{\mathrm{tilt}}\left(x_i\right)=-\frac{A_{\mathrm{man}\_\mathrm{<figure-callout\; id="2"\; label="tilt"\; filenames="H2009100133604E00021.png,H2009100133604E00023.png"\; state="\{\{state\}\}">tilt</figure-callout>}}}{2\&CenterDot;x_{\mathrm{os}}}\&CenterDot;x_i---\left(16\right)$

In the formula: A _{Max_tilt}Be roller declination manual adjustments coefficient, not carrying out the manual adjustments duration is 0, generate by ramp function during adjusting, and through amplitude limiting processing.

Compensated curve model that step 7, integrating step 1,2,3,4,5 calculate and step 6 manual adjustments additive curve model are formulated plate shape desired value setting curve model.

The flatness object curve that is actually used in the control of plate shape is superpose on the basis of basic flatness object curve compensated curve and the formation of manual adjustments curve.Concrete grammar is: the mean value that at first calculates the compensation rate and the manual adjustments amount of each effective measurement point, then the compensation settings of each measurement point is deducted this mean value and obtain being with steel tensile stress departure, departure is added to can obtain flatness object curve on the elementary object plate shape curve.The mean value of each effective measurement point compensation rate and manual adjustments amount is:

$\stackrel{\&OverBar;}{\mathrm{\&sigma;}}=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}[{\mathrm{\&sigma;}}_{\mathrm{cshc}}\left(x_i\right)+{\mathrm{\&sigma;}}_{\mathrm{geo}}\left(x_i\right)+{\mathrm{\&sigma;}}_i\left(x_i\right)+{\mathrm{\&sigma;}}_{\mathrm{os}\_\mathrm{edge}}\left(x_i\right)+---\left(17\right)$

${\mathrm{\&sigma;}}_{\mathrm{ds}\_\mathrm{edge}}\left(x_i\right)+{\mathrm{\&sigma;}}_{\mathrm{bend}}\left(x_i\right)+{\mathrm{\&sigma;}}_{\mathrm{tilt}}\left(x_i\right)]$

Then flatness object curve is:

σ(x _i)＝σ _base(x _i)+σ _cshc(x _i)+σ _geo(x _i)+σ _i(x _i)+σ _{os_edge}(x _i)+ (18)

σ _{ds_edge}(x _i)+σ _bend(x _i)+σ _tilt(x _i)-σ

Step 8, according to being the aspect of model requirement of several features point with actual plate shape measurement point broad ways interpolation, formulate the plate shape desired value setting curve model at each characteristic point place of plate width direction.

In plat control system,, be the several features point with actual plate shape measurement point broad ways interpolation, as shown in Figure 4 for the reduced data processing procedure.Calculate the tensile stress setting value at each characteristic point place then, the target deviation value that the tensile stress of controlling as plate shape distributes.Number axis X among Fig. 4 ₁Be the actual effectively measurement point distribution of plate width direction, the corresponding target tensile stress σ (x of each measurement point _i), number axis X ₂Be the characteristic point distribution of plate width direction, the corresponding target tensile stress σ who calculates through difference in each characteristic point place _i, the target tensile stress at these characteristic point places will be used for plate shape closed loop feedback control system as plate shape target deviation.

With number axis X ₂Go up each characteristic point i corresponding to number axis X ₁On a coordinate x, by number axis X ₂On characteristic point i be converted into number axis X ₁On the computational methods of a coordinate x as follows:

$x=\frac{n_1-1}{n_2-1}\&CenterDot;i---\left(19\right)$

In the formula: n ₁, n ₂Effective measuring section (point) number and the feature that are respectively plate width direction are counted.

Obtain number axis X ₂On characteristic point at number axis X ₁Behind the last corresponding coordinate x, determine that at first this coordinate is at number axis X ₁On two boundary point x _I-1And x _i, utilize the target tensile stress at the target tensile stress interpolation calculation coordinate x place at these two boundary point places again, computational methods are as follows:

$\mathrm{\&sigma;}\left(x\right)=\frac{\mathrm{\&sigma;}\left(x_i\right)-\mathrm{\&sigma;}\left(x_{i-1}\right)}{x_i-x_{i-1}}\&CenterDot;(x-x_{i-1})+\mathrm{\&sigma;}\left(x_{i-1}\right),(x_{i-1}\&le;x\&le;x_i)---\left(20\right)$

Number axis X then ₂On the target tensile stress at characteristic point i place be:

σ _i＝σ(x) (21)

Number axis X ₂The characteristic point at place, two ends does not need to handle, just peek axle X ₁The target tensile stress value of last fore side and first effective measurement point of transmission side portion, i.e. σ ₀=σ (x ₀), ${\mathrm{\&sigma;}}_{n_2-1}=\mathrm{\&sigma;}\left(x_{n_1-1}\right).$

Description of drawings

Fig. 1 is basic plate shape desired value curve map.

Fig. 2 installs the geometric error schematic diagram for coiling machine.

Fig. 3 is belt steel temperature measured value and temperature matched curve figure.

Fig. 4 is a several features point distribution map for the effective measuring section interpolation of strip width direction.

Fig. 5 is the cross-section panel-shaped distribution of band steel figure.

The specific embodiment

The present invention will be further described below in conjunction with drawings and Examples.

Present embodiment is disclosed to be the assignment procedure of certain 1250mm single chassis six roller reversable cold-rolling machine band steel shape control target value curve.What the plate shape measurement device adopted is homemade no roller-and-ring plate shape roller, roller footpath 350mm, 23 of measuring section numbers, barrel length 1350mm, measuring section width 52mm.Supplied materials specification (thick * wide): (2～3) * (800～1130) mm; Trimmed size (thick * wide): (0.3～0.82) * (800～1130) mm, material: ST12, mill speed 500m/min～600m/min, band steel exports temperature is 50 ℃～70 ℃.

1, the setting of basic plate shape desired value curve.

In the plat control system of 1250mm single chassis reversable cold-rolling machine, according to the requirement of rolling mill practice and subsequent handling to belt plate shape, the formulation principle of flatness object curve is: given supplied materials strip crown, first three passage with roll the back band not unstability be restrictive condition, being with steel that warpage does not take place after promptly rolling with assurance is precondition, reduce strip crown, latter two passage centralized Control plate shape makes finished strip have plate shape preferably as far as possible as far as possible.

In 1250mm cold-rolling mill shape aim curve setting model, adopt bar unit method to carry out the calculating that the band unstability is differentiated.If unstability thinks that then plate shape is bad; If unstability does not think that then plate shape can be accepted, and is relatively good.When carrying out the calculating of the good criterion of plate shape, differentiate factor ξ with one and judge plate shape condition, that is:

In the formula: ξ differentiates the factor for band steel unstability.

The setting of basic flatness object curve is a foundation to roll back band unstability discrimination model, takes into full account the requirement to belt plate shape of supplied materials band convexity and subsequent handling.The form of basic flatness object curve is a second-degree parabola, calculates parabolical amplitude by process computer, and sends plate shape computer to.The form of basic flatness object curve is:

${\mathrm{\&sigma;}}_{\mathrm{base}}\left(x_i\right)=\frac{A_{\mathrm{<figure-callout\; id="2"\; label="base\; x\; os"\; filenames="H2009100133604E00021.png,H2009100133604E00023.png"\; state="\{\{state\}\}">base</figure-callout>}}}{x_{\mathrm{os}}^{}}\&CenterDot;x_i^2-{\stackrel{\&OverBar;}{\mathrm{\&sigma;}}}_{\mathrm{base}}$

In the formula: σ _Base(x _i) be the setting value of each measuring section place band steel tensile stress deviation;

A _BaseFor process computer according to the band adjustment amount of plate crown and the amplitude of the basic flatness object curve that band unstability discrimination model calculates, symbol is relevant with the supplied materials pattern;

x _iFor being the coordinate of each measuring section of the origin of coordinates with band steel center, tape symbol, fore side be for negative, and transmission side is for just;

x _OsCoordinate for the effective measurement point of fore side strip edge portion;

σ _BaseBe average tensile stress.

Process computer calculates amplitude A _BaseThe time, according to different incoming band steel specifications,,, promptly differentiate under the situation of factor ξ＞1 guaranteeing that plate shape does not produce defective based on band unstability discrimination model, reduce strip profile as much as possible in former passages.Then focus on control panel shape, retainer belt steel ratio convexity unanimity in several passages in back.

Average tensile stress computing formula is:

${\stackrel{\&OverBar;}{\mathrm{\&sigma;}}}_{\mathrm{base}}=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\frac{A_{\mathrm{<figure-callout\; id="2"\; label="base\; x\; os"\; filenames="H2009100133604E00021.png,H2009100133604E00023.png"\; state="\{\{state\}\}">base</figure-callout>}}}{x_{\mathrm{os}}^{}}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="x\; i"\; filenames="H2009100133604E00021.png,H2009100133604E00023.png"\; state="\{\{state\}\}">x</figure-callout>}}_i^{}$

In the formula: n is that plate shape is effectively measured hop count.

Therefore in the plat control system of 1250mm cold-rolling mill, plate shape roller has 23 measuring sections, is with that maximum on the steel effectively to measure hop count be 23.Fig. 1 is basic plate shape desired value curve map, and as seen from Figure 1, the form of basic flatness object curve is a conic section.When each passage begins, after plate shape computer receives the amplitude of process computer transmission, judge at first whether the band steel produces sideslip, determine that according to the effective measurement point of strip edge portion of transmission side and fore side total effective measurement counts then, calculate the tensile stress setting value of each effective measurement point piecemeal, finally form complete flatness object curve.

Secondly, from phase balance condition, in the strip width scope, basic flatness object curve also should satisfy following formula by the band internal stress:

$\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\mathrm{\&sigma;}\left(x_i\right)=0$

2, the shape compensated curve is batched in setting

The 1250mm cold-rolling mill adopts the working method of batching the band steel on the coiling machine, and the scope of coil diameter is: φ 1100～φ 2000mm.The computing formula of batching the additional stress compensation is:

${\mathrm{\&sigma;}}_{\mathrm{cshc}}\left(x_i\right)=\frac{A_{\mathrm{<figure-callout\; id="2"\; label="cshc\; x\; os"\; filenames="H2009100133604E00021.png,H2009100133604E00023.png"\; state="\{\{state\}\}">cshc</figure-callout>}}}{x_{\mathrm{os}}^{}}\&CenterDot;\frac{d-d_{\min }}{d_{\max }-d_{\min }}\&CenterDot;{{\mathrm{<figure-callout\; id="2"\; label="x\; i"\; filenames="H2009100133604E00021.png,H2009100133604E00023.png"\; state="\{\{state\}\}">x</figure-callout>}}_i}^2$

In the formula: A _CshcBe the scroll correction factor, obtain according to the actual production technology Calculation by process computer;

D is current coiling machine coil diameter;

d _MinBe minimum coil diameter;

d _MaxBe maximum coil diameter.

3, set coiling machine the geometric error compensation curve is installed.As shown in Figure 2, because the restriction of equipment mounting condition coiling machine axis and the uneven situation of plate shape roll axis usually can occur, thereby bring certain influence to plate shape measurement, must in model, be compensated.Its computing formula is:

${\mathrm{\&sigma;}}_{\mathrm{geo}}\left(x_i\right)=x_i\&CenterDot;\frac{A_{\mathrm{<figure-callout\; id="2"\; label="geo"\; filenames="H2009100133604E00021.png,H2009100133604E00023.png"\; state="\{\{state\}\}">geo</figure-callout>}}}{2\&CenterDot;x_{\mathrm{os}}}\&CenterDot;E$

In the formula: A _GeoBe the linear compensation coefficient;

E is an elastic modelling quantity.

A _GeoUnit be I, it is a plate shape value, relevant with skew direction and angle excursion between coiling machine and the plate shape roll axis, characterized owing to the deflection between coiling machine axis and the plate shape roll axis, the plate shape deviation size that produces between plate shape roller fore side that causes and the transmission side.When the coiling machine transmission side is lower than fore side in the horizontal direction, A _GeoValue is being for just, otherwise for bearing.

4, set band steel transverse temperature difference compensated curve.Fig. 3 is belt steel temperature measured value and temperature matched curve figure.Stain is the observed temperature value among the figure; Solid line is the temperature matched curve.Concrete application and computational methods are as follows:

After using infrared radiation thermometer to survey out last each position temperature of frame outlet band steel, can determine its Temperature Distribution function by the curve match.Through the temperature difference distribution function after the Mathematical treatment be:

t(x)＝ax ⁴+bx ³+cx ²+dx+m

In the formula: a, b, c, d, m are the coefficient of the temperature difference distribution function after the curve match, and x is a strip width direction coordinate.

5, set strip edge portion attenuate compensated curve.

According to the situation of edge thinning in producing, respectively select several measurement points to compensate at fore side and transmission side.

Fore side compensation computing formula is:

${\mathrm{\&sigma;}}_{\mathrm{os}\_\mathrm{edge}}\left(x_i\right)=\frac{A_{\mathrm{edge}}+A_{\mathrm{man}\_\mathrm{edge}}}{{(x_{\mathrm{os}}-x_{\mathrm{os}\_\mathrm{edge}})}^2}\&CenterDot;{(x_i-x_{\mathrm{os}\_\mathrm{edge}})}^2,(x_{\mathrm{os}}\&le;x_i\&le;x_{\mathrm{os}\_\mathrm{edge}})$

In the formula: A _EdgeBe the edge thinning penalty coefficient, determine, calculate, send to plate shape computer by process computer according to the strip edge portion attenuate situation that occurs in producing;

A _{Man_edge}Be the manual adjustments amount of edge thinning coefficient, this is generated by ramp function in order to tackle in the production edge thinning and constantly to change and setting, and through amplitude limiting processing;

x _{Os_edge}For lighting from first effective measurement of fore side, last has the measurement point coordinate of edge thinning compensation.

Then fore side carries out the measurement point number of edge thinning compensation and is:

n _os＝|x _os-x _{os_edge}|

The edge thinning compensation computing formula of transmission side is:

${\mathrm{\&sigma;}}_{\mathrm{ds}\_\mathrm{edge}}\left(x_i\right)=\frac{A_{\mathrm{edge}}+A_{\mathrm{man}\_\mathrm{edge}}}{{(x_{\mathrm{ds}}-x_{\mathrm{ds}\_\mathrm{edge}})}^2}\&CenterDot;{(x_i-x_{\mathrm{ds}\_\mathrm{edge}})}^2,(x_{\mathrm{ds}\_\mathrm{edge}}\&le;x_i\&le;x_{\mathrm{ds}})$

In the formula: x _{Ds_edge}Light for do first effective measurement of side from biography, last has the measurement point coordinate of edge thinning compensation.

The measurement point number that transmission side carries out the edge thinning compensation is:

n _ds＝|x _ds-x _{ds_edge}|

Edge thinning situation according to occurring in 1250 mill milling technologies and the production generally makes fore side and biography

The measurement point number of moving side portion compensation is identical, i.e. n _Os=n _Ds=5.

6, set roller and inclination manual adjustments additive curve.

A, roller manual adjustments additive curve

${\mathrm{\&sigma;}}_{\mathrm{bend}}\left(x_i\right)=\frac{A_{\mathrm{man}\_\mathrm{<figure-callout\; id="2"\; label="bend\; x\; os"\; filenames="H2009100133604E00021.png,H2009100133604E00023.png"\; state="\{\{state\}\}">bend</figure-callout>}}}{x_{\mathrm{os}}^{}}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="x\; i"\; filenames="H2009100133604E00021.png,H2009100133604E00023.png"\; state="\{\{state\}\}">x</figure-callout>}}_i^{}$

In the formula: A _{Man_bend}Be roller manual adjustments coefficient, not carrying out the manual adjustments duration is 0, generate by ramp function during adjusting, and through amplitude limiting processing.

B, inclination manual adjustments additive curve

${\mathrm{\&sigma;}}_{\mathrm{tilt}}\left(x_i\right)=-\frac{A_{\mathrm{man}\_\mathrm{<figure-callout\; id="2"\; label="tilt"\; filenames="H2009100133604E00021.png,H2009100133604E00023.png"\; state="\{\{state\}\}">tilt</figure-callout>}}}{2\&CenterDot;x_{\mathrm{os}}}\&CenterDot;x_i$

In the formula: A _{Man_tilt}Be roller declination manual adjustments coefficient, not carrying out the manual adjustments duration is 0, generate by ramp function during adjusting, and through amplitude limiting processing.

On 1250mm milling train plate shape control operation picture,, associated button finishes the regulatory function of these two groups of manual adjustments additive curves by being set.

7, set plate shape desired value curve.

The flatness object curve that is actually used in the control of plate shape is superpose on the basis of basic flatness object curve compensated curve and the formation of manual adjustments curve.Concrete grammar is: the mean value that at first calculates the compensation rate and the manual adjustments amount of each effective measurement point, then the compensation settings of each measurement point is deducted this mean value and obtain being with steel tensile stress departure, departure is added to can obtain flatness object curve on the elementary object plate shape curve.The mean value of each effective measurement point compensation rate and manual adjustments amount is:

$\stackrel{\&OverBar;}{\mathrm{\&sigma;}}=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}[{\mathrm{\&sigma;}}_{\mathrm{cshc}}\left(x_i\right)+{\mathrm{\&sigma;}}_{\mathrm{geo}}\left(x_i\right)+{\mathrm{\&sigma;}}_i\left(x_i\right)+{\mathrm{\&sigma;}}_{\mathrm{os}\_\mathrm{edge}}\left(x_i\right)+$

${\mathrm{\&sigma;}}_{\mathrm{ds}\_\mathrm{edge}}\left(x_i\right)+{\mathrm{\&sigma;}}_{\mathrm{bend}}\left(x_i\right)+{\mathrm{\&sigma;}}_{\mathrm{tilt}}\left(x_i\right)]$

Then flatness object curve is:

σ(x _i)＝σ _base(x _i)+σ _cshc(x _i)+σ _geo(x _i)+σ _i(x _i)+σ _{os_edge}(x _i)+

σ _{ds_edge}(x _i)+σ _bend(x _i)+σ _tilt(x _i)-σ

8, be the characteristic point desired value curve that is used for plat control system with plate shape desired value curve interpolation.In 1250mm cold-rolling mill shape control system, for the reduced data processing procedure, with actual plate shape measurement point broad ways interpolation is 20 characteristic points, calculates the tensile stress setting value at each characteristic point place then, the target deviation value that the tensile stress of controlling as plate shape distributes.Fig. 4 is a several features point distribution map for the effective measuring section interpolation of strip width direction.Number axis X ₁Be the actual effectively measurement point distribution of plate width direction, the corresponding target tensile stress σ (x of each measurement point _i), number axis X ₂Be the characteristic point distribution of plate width direction, the corresponding target tensile stress σ who calculates through difference in each characteristic point place _i, the target tensile stress at these characteristic point places will be used for plate shape closed loop feedback control system as plate shape target deviation.

With number axis X ₂Go up each characteristic point i corresponding to number axis X ₁On a coordinate x, by number axis X ₂On characteristic point i be converted into number axis X ₁On the computational methods of a coordinate x as follows:

$x=\frac{n_1-1}{n_2-1}\&CenterDot;i$

In the formula: n ₁, n ₂Effective measuring section (point) number and the feature that are respectively plate width direction are counted.

Obtain number axis X ₂On characteristic point at number axis X ₁Behind the last corresponding coordinate x, determine that at first this coordinate is at number axis X ₁On two boundary point x _I-1And x _i, utilize the target tensile stress at the target tensile stress interpolation calculation coordinate x place at these two boundary point places again, computational methods are as follows:

$\mathrm{\&sigma;}\left(x\right)=\frac{\mathrm{\&sigma;}\left(x_i\right)-\mathrm{\&sigma;}\left(x_{i-1}\right)}{x_i-x_{i-1}}\&CenterDot;(x-x_{i-1})+\mathrm{\&sigma;}\left(x_{i-1}\right),(x_{i-1}\&le;x\&le;x_i)$

Number axis X then ₂On the target tensile stress at characteristic point i place be:

σ _i＝σ(x)

Number axis X ₂The characteristic point at place, two ends does not need to handle, just peek axle X ₁The target tensile stress value of last fore side and first effective measurement point of transmission side portion, i.e. σ ₀=σ (x ₀), ${\mathrm{\&sigma;}}_{n_2-1}=\mathrm{\&sigma;}\left(x_{n_1-1}\right).$

9, will be used for the closed loop plat control system, the result of use of analytical model through the plate shape desired value setting curve that above-mentioned steps is handled.

Table 1 1250mm cold-rolling mill finished product major parameter

Table 1 is a 1250mm cold-rolling mill finished product major parameter, after model promptly of the present invention drops into, and the situation of change of two cold rolling coil strip profiles.By data in the table as can be known, the supplied materials specification is respectively: 2.62 * 1020mm, 2.76 * 1053mm.During rolling band steel with middle convex cross section, the convexity of two winding steel gradually reduces 5.23 μ m and 5.62 μ m from the 28.4 μ m and the 29.7 μ m of supplied materials respectively.It is more that first three passage convexity is eliminated, and rolls the back strip profile and be evenly distributed, and satisfied the requirement of lower procedure to belt plate shape.

When reducing strip profile, belt plate shape has also been obtained good plate shape control effect.Fig. 5 is for after model drops into, and one group of extreme trace time band steel along the plate shape measurement value distribution map on the strip width direction.Product specification (thick * wide): 0.8 * 1090mm, material: ST12, mill speed 500m/min-600m/min.By data analysis as can be known, the cross-section panel-shaped deviation of band steel is controlled in the 10I basically.Simultaneously, the edge thinning situation has also obtained obviously alleviating, and through the practical application checking, edge thinning can be controlled in the 5 μ m.

Claims (12)

1. the modification method of a cold-rolled strip steel shape control desired value is characterized in that, according to subsequent handling the requirement and the band unstability model criterion of strip profile is set up basic plate shape desired value curve model; The adverse effect that plate shape measurement is caused at temperature, scroll and equipment alignment error in producing, calculate respectively to set up according to equipment ruuning situation and rolling technological parameter and batch shape compensated curve, coiling machine geometric error compensation curve, band steel transverse temperature difference compensated curve and strip edge portion attenuate compensated curve are installed, set the roller and the roller declination additive curve of manual adjustments plate shape, improve the flexibility of plate shape control; Simultaneously, be the several features point with actual plate shape measurement point broad ways interpolation, the reduced data processing procedure; And various compensated curves are added on the basic flatness object curve, thereby obtain to be used for the band steel shape control target value curve of closed-loop feed-back type plat control system.

2. the modification method of cold-rolled strip steel shape control desired value according to claim 1, it is characterized in that, describedly according to subsequent handling the requirement and the band unstability model criterion of strip profile are set up basic plate shape desired value curve model, the computational methods of its basic plate shape desired value curve are:

。

3. the modification method of cold-rolled strip steel shape control desired value according to claim 1 is characterized in that described computational methods of batching the shape compensation model are:

。

4. the modification method of cold-rolled strip steel shape control desired value according to claim 1 is characterized in that the computational methods that described coiling machine is installed the geometric error compensation model are:

。

5. the modification method of cold-rolled strip steel shape control desired value according to claim 1 is characterized in that the computational methods of described band steel transverse temperature difference compensation model are:

σ _t(x _i)＝-2.5(ax _i ⁴+bx _i ³+cx _i ²+dx _i+m)?。

6. the modification method of cold-rolled strip steel shape according to claim 1 control desired value is characterized in that, the computational methods of described strip edge portion attenuate compensation model are:

。

7. the modification method of cold-rolled strip steel shape control desired value according to claim 1 is characterized in that the computational methods of described roller manual adjustments additive curve model are:

。

8. the modification method of cold-rolled strip steel shape control desired value according to claim 1 is characterized in that the computational methods of described roller declination manual adjustments additive curve model are:

。

9. the modification method of cold-rolled strip steel shape control desired value according to claim 1, it is characterized in that, the manual adjustments additive curve model that compensated curve model that calculates in conjunction with claim 2,3,4,5,6 and claim 7,8 calculate, the mean value calculation method of each effective measurement point compensation rate and manual adjustments amount is:

。

10. the modification method of cold-rolled strip steel shape control desired value according to claim 1, it is characterized in that, the mean value calculation model of compensated curve model, manual adjustments additive curve model and each effective measurement point compensation rate and the manual adjustments amount that calculates in conjunction with claim 2,3,4,5,6,7,8,9, plate shape desired value setting curve model is:

σ(x _i)＝σ _base(x _i)+σ _cshc(x _i)+σ _geo(x _i)+σ _t(x _i)+σ _{os_edge}(x _i)+

σ _{ds_edge}(x _i)+σ _bend(x _i)+σ _tilt(x _i)-σ。

11. the modification method of cold-rolled strip steel shape control desired value according to claim 1, it is characterized in that, described is in the model of several features point with actual plate shape measurement point broad ways interpolation, and the coordinate of the plate width direction measurement point place number axis of plate width direction characteristic point correspondence is:

。

12. the modification method of cold-rolled strip steel shape control desired value according to claim 1, it is characterized in that, with described actual plate shape measurement point broad ways interpolation is the model of several features point, the coordinate of the plate width direction measurement point place number axis of the plate width direction characteristic point correspondence of calculating in conjunction with claim 11, the plate shape desired value setting curve at each characteristic point place of plate width direction is:

σ ₀＝σ(x ₀)

。

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