CN102236322B - Roller wear optimization control method for improving quality of band steel - Google Patents

Abstract

The invention relates to a roller wear optimization control method for improving the quality of band steel. The method comprises the following steps of: 1, classifying rollers according to roller materials; 2, acquiring the roller shape and surface temperature data of working rollers of a front rack and a rear rack in more than two rolling periods for different roller materials; 3, performing optimization processing on the acquired data; and 4, performing roller wear computation and optimization control, namely performing the roller wear computation by using optimized wear conversion factors according to different roller classes to realize the optimization control over band steel profiles and roller gaps. In the optimization control method provided by the invention, parameter optimization is performed according to different roller material types so as to improve the computational accuracy of a roller wear model and further improve band steel profile quality and roller gap control accuracy; moreover, measurement planning and parameter regulation processes are simple, operable and convenient to implement.

Description

A kind of roll wear optimal control method for improving strip quality

Technical field

The present invention relates to a kind of control method in the metallurgical production technology, is a kind of roll wear optimal control method specifically, particularly a kind of roll wear optimal control method for improving strip quality.

Background technology

In order to improve the belt plate shape quality, to boost productivity and lumber recovery, traditional hot tandem rolling unit generally all is equipped with plat control system in process machine system.Because the wearing and tearing of roll can't on-line measurement, plat control system calculates by the roll wear model and obtains.The roll wear value that model calculates and the deviation of actual value size directly have influence on rolling stability and belt plate shape quality.

In addition, as the direct roll gap model that affects the belt steel thickness control accuracy, usually also to consider the item that affects of roll wear, generally directly get the calculated value of wear model in the plat control system, thereby the computational accuracy of roll wear model also affect the roll gap control accuracy of milling train.

Roll wear is a slowly accumulation, and the factor that affects roll wear is a lot of and complicated, and operating mode is different, and wearing and tearing are also different.The mechanism model research of in the past on-the-spot breaker roll wearing and tearing is less, and is more to the Research on measuring technique of roll wear in the operation of rolling, obtains more wear law curve, but do not form so far more accurately roll wear computation model.

When the roll wear model that adopts foreign side to provide, because breaker roll material type is inconsiderate complete, especially when frame configuration high-speed steel rider, plat control system roll wear calculated value and actual value differ larger, cause the precomputations such as PC angle that plat control system calculates, bending roller force inaccurate, belt plate shape is difficult to control, and band steel toe overtaking wave shape is obvious.In addition, because the cumulative effect of the roll wear error of calculation, increasing when the roller figure place of roll, when plat control system surpassed to a certain degree to the departure of strip, plat control system can't control effectively to strip.

And roll wear and rhythm of production, chilled water and lubricating rollers, rolling procedure, roll material etc. are closely related, the wear model parameter of roll is steady state value in the plat control system that foreign side provides, to adjust by the condition of production at production line operation initial stage, through production in a few years, rolling procedure and rolling rhythm change a lot with the operation initial stage, these change the reflection of obtaining in the model that foreign side provides, thereby has affected the control accuracy of belt plate shape control system and roll gap model yet.

At publication number CN 101158984A, name is called in a kind of roll wear mathematical model optimizing method patent of the CSP of improvement product quality, its gordian technique is the bar strip continuous casting and rolling flow path for single, double stream production, the roll wear model adopts two sets of data, and can select according to the production automatic discrimination of single, double stream, thereby the roll wear calculated value is conformed to actual value, improve the strip shape quality with steel, enhance productivity and lumber recovery, promote at high proportion thin size hot-rolled plate production.And all do not relate to for Hot Continuous Rolling Mill Roll wearing and tearing Optimized-control Technique at present.

Summary of the invention

The technical problem to be solved in the present invention is: a kind of roll wear optimal control method for improving strip quality is provided, this optimal control method is optimized the roll wear model parameter by the roll of distinguishing unlike material, thereby improves belt plate shape quality and roll gap control accuracy.

In order to solve the problems of the technologies described above, the invention provides a kind of roll wear optimal control method for improving strip quality, the method may further comprise the steps:

Step 1: the roll classification, classify by the roll material breaker roll;

The roll configuration situation of different hot rolling lines is different.From at present known roll, can roughly be divided into the material of roll: high Gr grain roll, high Gr cast steel roll, high-speed steel roll, chilled cast iron roll (grey core), chilled cast iron roll (ball core), modified chilled cast iron, CPC (connecting the coating method of watering) high-speed steel roll seven class roll materials.

Step 2: the roll data acquisition for every kind of roll material, gathers two above rolling cycles front and back frame working rollers and surface temperature; Be preferably the rolling data that gathers 4 to 10 cycles.

For carrying out accurate parameter adjustment, need to guarantee the accurate of measurement data.In the DATA REASONING process, follow following flow process:

● measure the item

1. the rolling front shape of working roll up/down working rolls of frames (all);

2. the rolling front work roll surface temperature up/down working rolls of frames (all);

3. shape of working roll after the rolling cooling (all up/down working rolls of frames);

4. work roll surface temperature after the rolling cooling (all up/down working rolls of frames);

5. every coiled strip steel rolling data of measuring object roller system;

6. the roll information of measuring object roller system.

● measuring method

1. use roll shape instrument (roll forming of the roll measurement mechanism) to measure;

2. measured to the transmission side direction by active side;

3. measure beginning and end position General Definition at distance working roll end 20mm;

4. the spacing setting of roll shape instrument measurement is 5mm;

5. work roll surface temperature: at 3 points of distance working roll work side 150mm, central authorities and transmission side 150mm, measure with contact tehermometer.

Step 3: data-optimized processing, the data of utilizing step 2 to gather, total wear extent of the corresponding rolling cycle working roll of analog computation, and with the actual wear amount contrast of relevant work roller, adopt linear regression method optimization wearing and tearing reduction coefficient;

Calculate the wear extent that a rolling coiled strip steel produces at working roll

Working roll and with between steel and the friction between working roll and backing roll all can make working roll produce wearing and tearing.The wearing and tearing variation is a slowly process of accumulation, and its computational accuracy exerts an influence to strip crown setting, strip flatness control, strip surface quality improvement.The roll wear very difficulty of wear extent computing formula of deriving theoretically, usually consider the principal element of the impact wearing and tearing such as roll-force, mill length, roll material, wearing and tearing distances (contact arc length) after, adopt statistical regression model to calculate roll wear.

The roll wear computation model is:

ΔW(i，j)＝{a _w(i)·D _WR(i)+b _w(i)}·A(i，j) ^α(i)·B(i) ^β(i)·C(i) (1)

In the formula:

Δ W (i, j): a rolling coiled strip steel i frame, j order wear extent:

I: shelf number;

J: being 1-N, is the each point sequence number that the working roll length direction is got a point every a fixed range e (usually getting 5mm), and N is that roll length is that N=L/e is counted in total calculating on the barrel length direction of L;

A (i, j) is roll-force effect item;

B (i) is distorted area geometric influence item;

C (i) is rolled band steel effect length item;

D _WR(i): the diameter of i frame working roll;

a _w(i) wearing and tearing reduction coefficient work roll diameter item is 0;

b _w(i) wearing and tearing reduction coefficient distorted area geometric influence item;

α (i) draught pressure influence coefficient;

β (i) frictional distance influence coefficient.

Wherein, calculate the total wear extent of roll that rolling cycle produces, after a rolling cycle finishes, total wear extent of roll barrel each point equal this rolling scaduled in all with cumulative in body of roll corresponding point of steel wear extent, its mathematical expression is:

$\left\{\begin{array}{c}W(i,1)=\underset{k=1}{\overset{p}{\mathrm{\Σ}}}\mathrm{\Δ}{W}^k(i,1)\\ W(i,2)=\underset{k=1}{\overset{p}{\mathrm{\Σ}}}\mathrm{\Δ}{W}^k(i,2)\\ \·\·\·\\ W(i,N)=\underset{k=1}{\overset{p}{\mathrm{\Σ}}}\mathrm{\Δ}{W}^k(i,N)\end{array}\right.---\left(2\right)$

In the formula 2: Δ W ^k(i, j) is the wear extent that the k coiled strip steel produces at i frame, j point,

W (i, 1), W (i, 2) ..., W (i, N) be respectively after a rolling cycle the i frame body of roll the 1st point, 2 points ..., total wear extent of producing of N point, the curve that is linked to be is roll and calculates the wear curve profile, get the mean value that amounts to 50 points of barrel length direction middle position both sides as the calculating wear extent of these roll central authorities, be designated as

P is total band coil of strip number of a rolling cycle.

Adopt linear regression analysis optimization wearing and tearing reduction coefficient, in the formula 1, because wearing and tearing reduction coefficient work roll diameter item gets 0 usually, so the roll wear amount is the linear model relevant with the geometric influence item again.

To the upper and lower working roll of each frame, adopt respectively the relatively actual wear and calculating wearing and tearing (each rolling cycle point of working roll barrel length direction middle position, taked the data in several cycles that several points are just arranged), utilize linear regression to adjust the wearing and tearing reduction coefficient of roll, reach the purpose of optimizing the wearing and tearing computation model.

To every kind of roll material, each frame upper working rolls and lower working rolls, to calculate attrition value as horizontal ordinate, the actual measurement attrition value is ordinate, with data pair

Be drawn on the figure, find from the linear equation of each point square error minimum by linear regression analysis

y＝K _bw·x (3)

In the formula, K _BwAdjustment multiple for the wearing and tearing reduction coefficient multiply by K with former wearing and tearing reduction coefficient _BwAfter, the wearing and tearing reduction coefficient after just obtaining optimizing.

To all roll materials, the upper working rolls and lower working rolls of institute's organic frame is used linear regression to formula 3 respectively and is tried to achieve K _Bw

Pass through said method, suppose that mm finishing mill unit has 7 kinds of roll materials, then can obtain one large little be the parameter form of 7 (roll material type) * 7 (frame number) * 2 (upper working rolls and lower working rolls), wearing and tearing reduction coefficient distorted area geometric influence item coefficient is deposited in the inside.

Step 4: roll wear calculates and optimal control, the wearing and tearing reduction coefficient after optimizing is used for roll wear by different roll classification calculates, and realizes the optimal control to belt plate shape and roll gap.

Wearing and tearing reduction coefficient after optimizing is stored in process computer with form, is used for the On-line Control of wear model.According to used roll type of current rolling cycle, place frame and the corresponding wearing and tearing of upper working rolls and lower working rolls inquiry reduction coefficient, call again that wear model carries out in line computation in the plat control system.The wear data that calculates is used for plat control system control on the one hand with the plate shape of steel, is used on the other hand the roll gap that the roll gap model is controlled each frame.

Optimal control method of the present invention, minute different roll material types are carried out parameter optimization, can improve roll wear model computational accuracy, have improved thus strip shape quality and roll gap control accuracy with steel; And measurement setup and the parameter adjustment process is easy operates is convenient to implement.

Description of drawings

Fig. 1 is the synoptic diagram of the different subregions of roll wear calculating;

Fig. 2 is F5 frame parametric regression result schematic diagram;

Fig. 3 is F6 frame parametric regression result schematic diagram;

Fig. 4 is F7 frame parametric regression result schematic diagram.

Embodiment

Below, for a more detailed description to the present invention by reference to the accompanying drawings with embodiment.These embodiment only are the descriptions to best mode for carrying out the invention, scope of the present invention are not had any restriction.

Embodiment

At first hot continuous rolling unit roll wear computation model (only calculating the wear extent that a rolling coiled strip steel produces) is described.

Working roll and with between steel and the friction between working roll and backing roll all can make working roll produce wearing and tearing.The wearing and tearing variation is a slowly process of accumulation, and its computational accuracy exerts an influence to strip crown setting, strip flatness control, strip surface quality improvement.

The wearing and tearing minute permanent worn area in middle part and limit section concentrate worn area two parts.The main cause that forms the wearing and tearing aggravation of limit section is that limit section temperature reduces, loads in enhancing and the rolled piece metal three-dimensional flow of limit section zone effect.

As shown in Figure 1, different according to steel and roll contact position are divided into 7 parts with roll: middle part 14; Left and right the 1st limit section 11,11 '; Left and right the 2nd limit section 12,12 '; Left and right the 3rd limit section 13,13 '.For the difference of 7 part wear conditions, calculate respectively the wear extent of regional.L among Fig. 1 is band steel length, and S, T are band steel both sides section, O band steel center line.

Dw0 among Fig. 1, dw1, dw2, dw3 is for being used for the length of subregion; Kw1, kw2 are the gain coefficient that roll-force distributes along strip width.Dw0=162mm in the present embodiment, dw1=28.5mm, dw2=0, dw3=30mm, kw1=1.14, kw2=1, by dw0, dw1, dw2, the distance of the 1st limit section, the 2nd limit section, the 3rd limit section about four parameters of dw3 can be made.

Calculate the computation model of the wear extent that causes behind rolling every coiled strip steel:

ΔW(i，j)＝{a _w(i)·D _WR(i)+b _w(i)}·A(i，j) ^α(i)·B(i) ^β(i)·C(i) (1)

In the formula:

Δ W (i, j): a rolling coiled strip steel i frame, j order wear extent, unit: mm:

I: shelf number;

J: being 1-N, is the each point sequence number that the working roll length direction is got a point every a fixed range e, and N is that roll length is that total calculating is counted on the barrel length direction of L, N=L/e,

This routine e gets 5mm, L=2280mm, then N=457;

A (i, j) is roll-force effect item, unit: dimensionless;

B (i) is distorted area geometric influence item, unit: dimensionless;

C (i) is rolled band steel effect length item, unit: mm;

D _WR(i): the diameter of i frame working roll, unit: mm;

a _w(i) wearing and tearing reduction coefficient work roll diameter item is 0;

b _w(i) wearing and tearing reduction coefficient distorted area geometric influence item, unit: dimensionless;

α (i) draught pressure influence coefficient;

β (i) frictional distance influence coefficient.

Above-mentioned A (i, j), B (i), C (i), D _WR(i) item is relevant with rolling scaduled and rolling operating mode, that is, under given rolling procedure (rolling scaduled), the basic influence factor of every coiled strip steel wearing and tearing is that mill length, roll-force and contact arc length etc. all can calculate.

Above-mentioned a _w(i), b _w(i), α (i), β (i) are the undetermined parameter of roll wear model, wherein a _w(i) usually get 0, and α (i), β (i) can maintain static, thereby the parameter that needs to adjust is b _w(i), this patent is exactly by adjusting b _w(i) so that the calculating of working roll middle position wearing and tearing are approaching as far as possible with the actual measurement attrition value.

Formula (1) is exactly the roll wear computation model, and wear extent mainly is subjected to the impact of the factors such as roll-force, mill length and contact arc length, and roll-force and mill length product are larger, and then wear extent is larger.Because the wear condition of different subregions is different, so the attrition value on body of roll each point is different, it distributes shown in 10 among Fig. 1 along barrel length.In addition, the present invention defines Δ W (i, j) only just has value on the steel edge portion S of steel and roll contact portion, point in T both sides dw3 (the being generally 30mm) scope, and all the other points all are 0.

Total wear extent that a rolling cycle (rolling scaduled, as usually will to want rolling tens coiled strip steels) produces is calculated (wear extent of each coiled strip steel that superposes).Every rolling coiled strip steel can produce certain wearing and tearing at roll, and the wearing and tearing size is calculated by formula 1.After the rolling scaduled end, the total wear extent of roll barrel each point equals this, and all are with cumulative in body of roll corresponding point of steel wear extent in the works, and computing formula is as follows:

$\left\{\begin{array}{c}W(i,1)=\underset{k=1}{\overset{p}{\mathrm{\Σ}}}\mathrm{\Δ}{W}^k(i,1)\\ W(i,2)=\underset{k=1}{\overset{p}{\mathrm{\Σ}}}\mathrm{\Δ}{W}^k(i,2)\\ \·\·\·\\ W(i,N)=\underset{k=1}{\overset{p}{\mathrm{\Σ}}}\mathrm{\Δ}{W}^k(i,N)\end{array}\right.---\left(2\right)$

In the formula 2: Δ W ^k(i, j) is the wear extent that the k coiled strip steel produces at i frame, j point,

W (i, 1), W (i, 2) ..., W (i, N) be respectively after a rolling cycle the i frame body of roll the 1st point, 2 points ..., total wear extent of producing of N point, the curve that is linked to be is roll and calculates the wear curve profile.

P is total band coil of strip number of a rolling cycle.

The below is given in certain hot rolling and connects a concrete calculated example using this patent method on the production line.Total band coil of strip of this rolling cycle is counted p=70, and the roll material type is high Gr cast steel roll.The collection of the measured data of wearing and tearing is according to the method described above obtained corresponding computational data simultaneously from process machine data storehouse, as Model Parameter Optimization basic data (as shown in table 1).

Then, adopt the wear and tear optimization of reduction coefficient of linear regression analysis, regression result is shown in Fig. 2～4, and wherein, horizontal ordinate is calculated value, and ordinate is measured value.The final argument adjustment the results are shown in Table 2.

The working roller abrasion measured value that table 1 regretional analysis is used and calculated value [um of unit]

Illustrate: Top represents top working roll, and Bottom represents bottom working roll.

Table 2 wear model wearing and tearing reduction coefficient parameter optimization result

On the F5

Under the F5

On the F6

Under the F6

On the F7

Under the F7

Original parameter

1.53E-05

1.73E-05

2.59E-05

2.27E-05

4.34E-05

4.00E-05

Optimal Parameters

2.50E-05

2.71E-05

2.59E-05

3.22E-05

5.49E-05

4.64E-05

Adjust multiple

1.6404

1.5628

0.9992

1.4154

1.2643

1.1616

More than the linear regression analysis of 3 upper and lower working rolls of frame shown in Fig. 2-4, wherein, horizontal ordinate is calculated value, ordinate is measured value.Straight line on the accompanying drawing is exactly the result of linear regression, and straight slope is adjusted coefficient exactly.

Optimal control method of the present invention, minute different roll material types are carried out parameter optimization, can improve roll wear model computational accuracy, have improved thus strip shape quality and roll gap control accuracy with steel; And measurement setup and the parameter adjustment process is easy operates is convenient to implement.

Claims (6)

1. roll wear optimal control method that be used for to improve strip quality is characterized in that the method may further comprise the steps:

Step 1: the roll classification, classify by the roll material breaker roll;

Step 2: the roll data acquisition for every kind of roll material, gathers two above rolling cycles front and back breast roller roll shapes and surface temperature data;

Step 3: data-optimized processing, the data of utilizing step 2 to gather, total wear extent of the corresponding rolling cycle roll of analog computation, and with the actual wear amount contrast of corresponding roll, adopt linear regression method optimization wearing and tearing reduction coefficient;

Step 4: roll wear calculates and optimal control, the wearing and tearing reduction coefficient after optimizing is used for roll wear by different roll classification calculates, and the wearing and tearing reduction coefficient after the optimization is stored in process computer with form, is used for the On-line Control of wear model; According to used roll type of current rolling cycle, place frame and the corresponding wearing and tearing of top and bottom rolls inquiry reduction coefficient, call again that wear model carries out in line computation in the plat control system.

2. the optimal control method described in according to claim 1, it is characterized in that: described roll classification can be divided into by roll material: coating method high-speed steel roll seven class roll materials water in high Gr grain roll, high Gr cast steel roll, high-speed steel roll, chilled cast iron roll, chilled cast iron roll, modified chilled cast iron and company.

3. the optimal control method described in according to claim 1, it is characterized in that: the rolling cycle of described roll data acquisition is 4 to 10 cycles.

4. the optimal control method described in according to claim 1, it is characterized in that: in the described data-optimized processing procedure, the roll wear computation model of employing is:

ΔW(i,j)={a _w(i)·D _WR(i)+b _w(i)}·A(i,j) ^a(i)·B(i) ^β(i)·C(i)

In the formula:

Δ W (i, j): a rolling coiled strip steel i frame, j order wear extent, unit: mm:

I: shelf number;

J: being 1-N, is the each point sequence number that the roll length direction is got a point every a fixed range e, and N is that roll length is that N=L/e+1 is counted in total calculating on the barrel length direction of L;

A (i, j) is roll-force effect item, unit: dimensionless;

B (i) is distorted area geometric influence item, unit: dimensionless;

C (i) is rolled band steel effect length item, unit: mm;

D _WR(i): the diameter of i breast roller, unit: mm;

a _w(i) wearing and tearing reduction coefficient roller diameter item is 0;

b _w(i) wearing and tearing reduction coefficient distorted area geometric influence item, unit: dimensionless;

α (i) draught pressure influence coefficient;

β (i) frictional distance influence coefficient.

5. the optimal control method described in according to claim 1 is characterized in that: calculating the total wear extent formula of roll that a rolling cycle produces is:

$\left\{\begin{array}{c}W(i,1)=\underset{k=1}{\overset{p}{\mathrm{\Σ}}}\mathrm{\Δ}{W}^k(i,1)\\ W(i,2)=\underset{k=1}{\overset{p}{\mathrm{\Σ}}}\mathrm{\Δ}{W}^k(i,2)\\ ...\\ W(i,N)=\underset{k=1}{\overset{p}{\mathrm{\Σ}}}\mathrm{\Δ}{W}^k(i,N)\end{array}\right.$

In the formula: i: shelf number;

J: being 1-N, is the each point sequence number that the roll length direction is got a point every a fixed range e, and N is that roll length is that N=L/e+1 is counted in total calculating on the barrel length direction of L;

Δ W ^k(i, j) is the wear extent that the k coiled strip steel produces at i frame, j point,

W (i, 1), W (i, 2) ..., W (i, N) be respectively after a rolling cycle the i frame body of roll the 1st point, 2 points ..., total wear extent of producing of N point, the curve that is linked to be is roll and calculates the wear curve profile, get the mean value that amounts to 50 points of barrel length direction middle position both sides as the calculating wear extent of these roll central authorities, be designated as

P is total band coil of strip number of a rolling cycle.

6. the optimal control method described in according to claim 1, it is characterized in that: described linear regression method is specially, and to every kind of roll material, each frame top and bottom rolls, to calculate attrition value as horizontal ordinate, the actual measurement attrition value is ordinate, with data pair

Be drawn on the figure, find from the linear equation of each point square error minimum by linear regression analysis

y=K _bw·x

In the formula, K _BwAdjustment multiple for the wearing and tearing reduction coefficient multiply by K with former wearing and tearing reduction coefficient _BwAfter, the wearing and tearing reduction coefficient after just obtaining optimizing,

I: shelf number;

J: being 1-N, is the each point sequence number that the roll length direction is got a point every a fixed range e, and N is that roll length is that total calculating is counted on the barrel length direction of L, N=L/e+1,

W (i, 1), W (i, 2) ..., W (i, N) be respectively after a rolling cycle the i frame body of roll the 1st point, 2 points ..., total wear extent of producing of N point, the curve that is linked to be is roll and calculates the wear curve profile, get the mean value that amounts to 50 points of barrel length direction middle position both sides as the calculating wear extent of these roll central authorities, be designated as

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