SU1516158A1 - Apparatus for automatic control of strip thickness in rolling - Google Patents

Abstract

The invention relates to rolling, in particular to control and regulating devices of rolling mills, and can be used to reduce the longitudinal and transverse thickness variations of the strips rolled on continuous rolling mills, in particular on continuous broadband hot rolling mills. The purpose of the invention is to improve the accuracy of adjusting the thickness of the head sections of the strip and the stability of rolling by ensuring the dependence of the magnitude of the correction pressure in the hydraulic cylinders before the strip enters the stand from the stand deformation. This goal is achieved by the fact that when the head of the strip enters the cage, the signals of the meter 13 and the setting device 14 force, using the adder 15 and the multiplying unit 16, to calculate the pressure decrease in the hydraulic cylinders resulting from the deformation of the cage and correct the specified pressure value. 1 il.

Description

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The invention relates to rolling, namely to the control and regulating drives of rolling mills, and can reduce the longitudinal and 11 () H1e) rolling thickness variations of the rolling mills, in particular continuous and wideband hot rolling mills.

The purpose of the invention is to improve the accuracy of the adjustment. Heads of the knots of Nolos and rolling stability by ensuring the dependence of the magnitude of the corrective pressure in the hydraulic cylinders is not allowed by the passage of the strip into the stand from the deformation of the stand.

fla drawing |; | 1 data; 1a structure diagram usg) 1sgva .1. I am an automatic), i, i; i: .i stripes during rolling.

The usi 1 poiic iiio for; pch:) the mathematical regulation of the T (), iuuiHi, i bands during rolling contains a hydra |) chi. pm1d | pl 1 pillows of the i-th r. -rungs, connected to i idrostation 2, sensor: and setting pad 4 .unit in hydraulic cylinders. first ich ki - () | ibix is connected to

hydrostation

HeiiiK po. u i.riiiio, and WTO-

through the first sum; | p K) P1pi amplify. S, sensor (i pa. 1st of Mi ra.i. ia in the i-th stand, sensor 7 pa. difference. mma., 1-1 / -th stand, 11cen. 1ed () vatno (soy.chiyennyss laxore- perator 8, M-1 / th ktetn, 11.) I, the second summation of the successful tracker I), r / p element 11, output to K) ) 11i ;; connected to the entrance of ||) ag.lepi wee ;;. : Jaemo1 o K, 12, the output of which (. (The cells with the current input su.m.my | 1uk) above1 ohsile S 5, the sensors 7 n (with metal connections are connected respectively t BTOjiM.M and ipeibHM inputs 11nteg ) Ator U, and WTO) he 5th move of second su.mir} K) one of usi; | ite, 1i K) is connected to the output of the Taxoi eHejnnopa 8 (i -) - ii ic.ieTii, meter 13 and set peach 14, - and . ingt-rolling and pos. Singleton, | soy uilennye adder 15 p M; ; yui1.1; O iot, Hi. output KoTOpoi o connect c;. () .. t); pa,; .-. ted to k, batch 12, from. merpe,:, l and. i. iarCHIK 14 usI, 1ITELN npoK. la.lKi; with; . .l.ii lii ll / .; G;: ;;: ccstvipno with dimensional and i; ::: i, 1; .. P1 total 5a 15, BT iiimi 3x0: 1 mpo / ki. M south of the K) is connected with the output--: i.naT iii - ka 4 dav. K Neither | -Idrotsi.11P1.1ra ..

The device works as an opraz.

During mill adjustments, the rolled product range (the strip in cages (no iT) is present on the setting units 4 and 14 of the pump bar, respectively, given by the values of Q 1 and P: pressure in the (1 cylinder of I resist bending of workers). AM.MCH and rolling force.

If the pressure Q in the hydraulic cylinder. | 1ax I is not equal to the specified value (,):; by the action of hydrostation 2, it begins to change, while the central station is B1 on the spindle, 5

0

0

five

0

five

0

0

five

does not compare with setpoint 4; wherein the pressure in the hydraulic cylinders is set equal to the given, i.e., Q,:, i, where QO is the initially specified pressure in the hydraulic cylinders.

The pressure drop AQc in the roll bending hydraulic system as the strip enters the stand can be determined from the known equation for a closed system

Q. V const, (1)

where Q and V are the pressure and volume of the working fluid in the hydraulic system, respectively.

The differential equation (1), the transition from infinitely small increments to the finite ones and taking into account that the change in volume V when the strip enters the stand is connected only with the deformation of the stand, we find the relationship between the pressure increment and the change in the position of the hydraulic cylinders Lx

Q -K QAx (2)

where K is shkanna, defined by the design parameters of the hydraulic system.

At the moment when the strip enters the cage, the pressure in the hydraulic system corresponds to the sum of 1x) Qiin (in accordance with the required strip profile) and the corrective Q .. pressure, i.e.

Q {{. {,. ) Q.,. ,,. ,, ,, (3) In turn, the parameter. Lx of the cortical deformation of the stand under the action of the pressure drop on the rolls as the strip enters the stand and, therefore, can be represented by the equation

(R.-Ro). (four)

where K is the coefficient that determines the interchange of work roll pillows

by the force of rolling;

P I: s; : given nominal force pro | attacks; I ll the initial force on the rolls (wuxi,; and the first rolls),

 in: I p,; 5, that .Q --- AQ. , we will present with, JV (,} 11 (4) the expression for reset. I; 1.;,.: c; i, iH (2) in the final form

Q. K (P .., Po) (Q ...., + AQ., ..), (5) | q K - K K is the proportionality coefficient.

Algorithm. Calculate Corrective Pressure. ::. determined from the condition

Q,., Q. (6)

1;). 1С1 avi15 condition (6) into equation (5) and having carried out the simplest transformations, 11 rays, I eat

 , P -P) Q-- (7)

(ia 11р;: к1 1ке there is a relation .., with K (P ... -Ro) "1, and the expression for calculating the compensating yes1, laziness (7) can be rewritten in a simplified form

 0. (Pm-Pn). Q., a., (8)

From 18) it can be seen that the KOMiii-Hcii hydraulic pressure device generation scheme should contain setting devices for rolling force and pressure in hydraulic cylinders, a roll force meter before entering the strip stand, and the rolling force meter, as is well known, performs this function, as well as multiplying device and adder.

When the head section of the rolled strip enters the (i-1) -th fly, the sensor 7 of the presence of metal in this stand is triggered and connects the output of the tachogenerator 8 to the input of the integrator 9. The voltage at the output of the integrator 9 begins to increase in time, and at the output of the summing amplifier 10 - according to law

, U, ft + K.U.

where Ki, K2 - transfer coefficients of the amplifier 10, respectively, on the first and second inputs; UT - output voltage

tachogenerator 8;

t is the integrator time constant;

t current time

When the voltage is LJ. reaches a fair value of Un, the threshold element 1I is triggered and connects the output 12 of the duplication unit 16 to the second input of summing amplifier 5 via the control M1 | 1Y key; the setpoint pressure is increased by the value Q ..:.: in accordance with the voltage of the signal at the output of the multiplying device, and the pressure in the hydraulic cylinders I reaches the value

, a .. + AQ.,.

The time I, at which the threshold element 11 is triggered, is determined by the time tt for the front end of the strip to pass the distance between the (| 1) th and i th cells AND the specified time t,; ahead of turning on the correction signal QaA before the entrance of the strip to the i-th stand

t1 - I /, t-i

LJ li1 (1, If y,

where L is the distance between (i-d) th and i-th

cages of the camp; V speed of the strip at the entrance to the i-th

stand.

The parameters m and 1 of the integrator and the threshold element are determined from the condition

 t-t. from where

,, and and, K, 4- utn, to

In the particular case of K, - Kj- 1 inu t

tt

 and

0

five

0

five

0

five

in MCM), 1h .iK.M 2

i.:P,.r i 1I

sg; mi: ь.:;

After entering the band in the i-th k.kch orao; The sensor 6 of the presence of metal in this stand melts and converts the integrator and the linear state corresponding to zero voltage at its output; the threshold element 11 is also translated, and the controlled state is opened. Given value; at the entrance of the hydro station 2 snon. with equal rzad.

The actual pressure) of the working side of the bone in the hydraulic cylinders, due to the deformation of the stand, is reset to the value AQt and becomes equal to

Q, (a., + AQ. A., - AQ Q.,. + Q, where AQ. (AQsa.-AQc) is the actual deviation of pressure in the hydraulic cylinders from a predetermined value.

At AQ3,., AQ ;, AQ, 0. a.:, I.e., the pressure in the hydraulic cylinders of the work rolls bending is equal to the specified value, which determines the equality of the specified cross-sectional profile of the rolled strip on its head sections and the stability of the rolling process.

The magnitude of the correction pressure AQia.i is determined by the product of the difference between the signals at the outputs of the setter 14 and the meter 17 of the rolling force and the signal at the output of the setter 4 of pressure in the hydraulic cylinders and, therefore, can be represented by

AQ,., L, -Rp) - d. L, where P1 is the proportionality coefficient, determined by the transmission coefficient on the second input of summing amplifier 5.

The coefficient P1 can be on experimental data mule

determined by odds, 4J2

 a ".

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The use of the proposed device in comparison with the known one will ensure a reduction in the sorting of the metal into the second grade due to shape defects by an average of 0.01% due to an increase in the accuracy of lyration of the thickness of the head portions of the STRIP; reduction of rejects on under-products and shape defects by an average of 0.005% due to an increase in the stability of the rolling process of the head sections of the strip.

Claims (1)

Invention Formula A device for automatic adjustment of the strip thickness during rolling, containing bending hydraulic cylinders c; kchk () c. connected to the hydraulic station, the sensor and the pressure gauge in the hydraulic cylinders, which are connected to the hydraulic station directly, and the second through the first summing amplifier, the metal presence sensor in the i-th stand, the metal presence sensor in the (1-1) -th stand, connected in series tachogenerator (| -1) -th stand, integrator, second summing force and threshold element, the output of which is connected to the control input of the controlled key, the output of which is connected to the second, input of the first summing amplifier, metal presence sensors are connected respectively correspondingly with the second and 1) input1m inputs of the integrator, and the second input of fiioporo cyMMiipyHMuei o amplifier is connected with the output of a tachogenerator (1-1) st stand, characterized in that, in order to improve the accuracy of controlling the thickness of the head sections of the strip and the rolling stability By providing the dependence of the magnitude of the correction pressure in the hydraulic cylinders before the strip enters the stand on the deformation of the stand, it is equipped with a rolling force gauge and setting unit and connected in series by an adder and duplicating unit whose output is connected to the input of the controlled key, the rolling force gauge and setting unit are respectively connected to the first and the second inputs of the adder, and the second input the multiplying unit is connected to the output of the pressure unit in the hydraulic cylinders.