SU1357100A1 - Automatic control system for accelerated cooling of rolled stock on exit side of section mill - Google Patents

Abstract

This invention relates to the automation of the process of thermal strengthening of rolled products on the output side of a rolling mill. The purpose of the invention is to improve the quality of rolled products. This is achieved by introducing an adaptive l parameter block for the model of the coefficient of heat transfer, a block for calculating the required rolling speed through an accelerated cooling unit, a comparison unit and a rolling motion speed correction unit through an accelerated cooling unit. Before the hire enters the cooling plant, the required water flow is calculated and determined according to the specified values of the process parameters, including the speed of the rolling stock. When a rental enters the cooling installation and the actual process parameters are obtained, the required speed of movement of the rental in the installation is fulfilled. The calculation of the required speed is carried out using the model of heat transfer coefficient. The parameters of the continuous model are refined in the adaptive identifier block, which makes it possible to take into account the effect on the heat transfer coefficient of a change in the heat exchange conditions between the cooled liquid and the heated metal. 1 hp f-ly, 1 ill. o 9 (L have eaten

Description

The invention relates to the technology of automatic control of rolling mills, in particular, to the automation of the process of thermal strengthening on the output side of a rolling mill.

The purpose of the invention is to improve the quality of rolled products.

The drawing shows a block diagram of an automatic control system for accelerated cooling of the rolled products on the output side of the section mill.

to the input of the rolling stock speed control circuit.

The system works as follows.

Signals from setpoint 8 of nominal values of rental parameters and cooling process (size R, rental temperature at the input of the installation of accelerated cooling T, rental temperature at the output of the installation of accelerated cooling of the movement speed of rolling Vj) go to the input system contains a sensor 1 of the computing device temperature 7 The calculation of the 15th required cooling flow rate. In addition, the inputs of the computing device 7 and the signals are received yes G20

rental tours at the entrance to the accelerated cooling unit, device 3 controlling the cross-sectional dimensions of the car, displacing speed sensor 4; neither hire, rolling temperature sensor 5 and the output of the accelerated cooling unit, sensor 6 of the cooler temperature at the accelerated cooling unit output.

A computing device 7 for calculating the required flow rate of the cooler, a sensor 8 of the nominal values of the rental parameters and a cooling process, an adaptive identifier of the parameters of the heat transfer coefficient model identifier 30 are entered into the control system circuit (- measurements, block 10 for calculating the required rolling speed through the accelerated cooling unit, the comparison unit 11, the setpoint correction unit 12 for the movement speed of the rolled stock through the accelerated cooling unit, the movement speed control circuit 13 and Coolant flow rate p 14. At the same time, the outputs of the rental temperature sensors 1 and 5 at the inlet and outlet of the accelerated cooling unit, respectively, of the rental speed sensor 4, the cross-sectional dimensions control device 3 are connected to the adaptive identifier inputs. The adaptive identifier output is connected to the input of the calculator the required moving speed of the procachik 6 of the cooler temperature; and from the output of the unit 10 for calculating the required moving speed of the rolling through the accelerated cooling unit.

In the computing device 7, the required flow rate of water required to cool the car for a given parameter of 25 meters t, t, V, R is calculated using the formula known from the theory of heat engineering, which for the cylinder is

Q rnVRMn

t, - t

H, d

H

(one)

35

40

the temperature of the car before cooling, C, t is the temperature of the car after

cooling, C, t is the temperature of the cooling water. WITH,

R is the outer radius of the rolled product (cylinder), m,

V is the speed of the passage through the cooling unit, m / s,.

m is a constant.

m

3600 JTf C

(2)

45

where C is the heat capacity of steel, kkDcgh

X ° C),

Р - steel density, kg / m, р - proportionality coefficient between heat transfer coefficient and water consumption per unit of surface cooled - steel density, kg / m, p - proportionality factor between heat return coefficient and water consumption per surface unit

kcal m C Signal from the output of the computational

not to the first input of the comparison block. The output of the velocity sensor is connected to the second input of the comparator unit. The output of the comparator unit is connected to the second input of the correction unit gg of the device 7, proportional to the distribution, to the first input of which the output of the setpoint speed channel is cooled to the counted value of the flow rate Q, is fed to the input of the regulator of the nominal values of the parameters. 14, where the specified output of the correction unit is processed (basic) flow rate is connected.

| where (-

chick 6 of the cooler temperature and from the output of the block 10 for calculating the required speed of moving the rolled stock through the accelerated cooling unit.

In the computing device 7, the required flow rate of water required for cooling the rolled products with the given parameters t, t, V, R is calculated using the formula known from the theory of heat engineering, which for the cylinder is

Q rnVRMn

t, - t

H, d

H

(one)

where (-

the temperature of the car before cooling, C, t is the temperature of the car after

cooling, C, t is the temperature of the cooling water. WITH,

R is the outer radius of the rolled product (cylinder), m,

V is the speed of the passage through the cooling unit, m / s,.

m is a constant.

(-

m

3600 JTf C

(2)

30 | where (-

45

where C is the heat capacity of steel, kkDcgh

50

X ° C),

P - steel density, kg / m, p - proportionality coefficient between heat transfer coefficient and water consumption per unit of cooled surface unit 7, proportional to the calculated value of the flow rate Q of the cooler, goes to the input of the regulator 14, where the specified (basic ) value of consumption.

kcal m C Signal from the output of the computational

Proceedings 7, proportional to the diluted value of the flow rate Q cooled, the regulator goes to the input where the specified local reserve value of the flow is processed.

3135

However, numerous data indicate that controlling the flow of water according to formula (1), taking into account the deviations of the parameters t, t, R, V from the given values, does not allow the desired temperature to be maintained with the required accuracy. Firstly

This is due to the fact that

heat transfer is a function of not only b, since it is necessary to adapt them to

the consumption of water per unit surface of the metal being cooled, as well as the temperature of the metal before and after cooling.

In addition, water flow control is inertial due to the difficulty of implementing high-speed flow control actuators.

Therefore, to compensate for deviations of the rolling temperature after cooling t at a given Q, control of the speed of movement of the prostate is used through an accelerated cooling installation, which is calculated in block 10 for calculating the required speed of rolling of rolling using the formula of a regular thermal regime

V,

Where

cooling unit length (constant)

the measured value of the outer radius of hire, the value of the heat transfer coefficient.

In this case, the heat transfer coefficient is represented by the model:

(four)

R dL

- bt, ct

2

where a, b, c are coefficients.

The cooling of the metal, which is heated significantly above the temperature of the coolant, usually occurs under film, transitional and bubble boiling regimes. Changes in boiling regimes occur with a decrease in the temperature of the metal surface. In this case, the heat transfer coefficient increases significantly. The heat transfer coefficient of bubble boiling is on the order of dock and more than film. Thus, the lower the temperature-metal before cooling and the lower at the end of cooling, the Bbmje average heat transfer coefficient.

Formula (4) in the linear approximation expresses the described physical phenomenon. The coefficients a, b, c of this formula depend on the thermophysical properties of the coolant, its temperature and the flow rate,

In this connection, besides the initial determination of the coefficients a,

15

25 o

20

thirty

During the operation of the system, seasonal fluctuations in coolant temperature and changes in the intensity of fluid outflow due to aging of the supply pipes are possible. The initial values of the coefficients can be obtained using a regression analysis apparatus. The adaptation of the coefficients a, b, c to improve the accuracy of control of the cooling process is carried out in node 9 of the adaptive identifier. The adaptation of the coefficients is performed according to the well-known Kacmage algorithm.

Thus, the goal is set to increase the accuracy of control of the process of accelerated cooling of rolled products.

Claims (2)

1. An automatic control system for accelerated cooling of rolled products on the output side of the section mill, comprising rental temperature sensors at the output and input of the accelerated cooling unit, a rolling movement speed sensor, a device for controlling the cross-sectional dimensions of the rolled product, a cooling process sensor, a temperature sensor for the cooler , computing device for calculating the required flow rate of the cooler, the flow controller of the cooler and the control circuit of the speed of movement and the cooler temperature sensor and the temperature sensor of the cooler are connected to the inputs of the computing device for calculating the required flow rate of the cooler, the output of which is connected to the input of the coolant flow regulator, in order to improve the quality of the rolled metal, it is equipped with an adaptive identifier of parameters of the heat-transfer coefficient model, a unit for calculating three 0 boil rolling speed through an accelerated cooling unit, a comparator unit and a setpoint correction unit for moving car speed through an accelerated cooling unit, the outputs of the rolling temperature sensors at the inlet and outlet of the accelerated cooling unit, the rolling speed sensor, the device for controlling the cross-sectional dimensions of the rolled products, outputs channels of a given cooling temperature and a given speed of moving the rental unit of the nominal rolling and process parameters cooling units are connected to the inputs of the adaptive identifier of the parameters of the heat transfer coefficient model, the output of which is connected to the first input of the unit for calculating the required rolling speed, the other sensors of the desired rolling speed are connected to the outputs of the rolling temperature sensor at the input of the accelerated cooling unit rolled section, the channel output setpoint cooling temperature of the rental unit of the nominal parameters of the rental and about The cooling unit, the output of the unit for calculating the required rolling speed is connected to the first input of the comparator unit, to the second flow of which the output of the rolling speed sensor is connected, the output of the comparator unit is connected to the second input of the correction unit, to the first input of which the output of the nominal setpoint speed channel is connected parameters, the output of the correction unit is connected to the input of the control circuit rolling speed. one 2. The system according to claim 1, characterized in that the node of the adaptive identifier of the parameters of the model of the heat transfer coefficient comprises a coefficient memory block, a calculation block 0 0 heat transfer coefficients, parameter memory block, calculation block, actual heat transfer coefficient, parameter D calculation block, three new coefficients calculation blocks, the outputs of new coefficients calculation blocks are connected to the input of the coefficient memory block, the first output of which is connected to the first inputs of new calculation blocks coefficients, the second inputs of which are connected to the first output of the parameter calculation unit D, the first input of which is connected to the first input of the actual heat transfer coefficient calculation unit and from the third The third input of the new coefficient calculation block is connected to the first output of the parameter memory block, which is also connected to the first input of the block for calculating the actual heat transfer coefficient, the second and 5 the third inputs of which are connected to the second and third outputs of the parameter memory block, the fourth and fifth outputs of which are connected to the second and third inputs of the parameter D calculation block, the fourth input of which is connected to the output of the actual heat transfer coefficient calculation block, the output of the coefficient memory block is connected with the first input of the heat transfer coefficient calculation unit, the second input  The heat transfer coefficient calculation unit is connected to the first input of the parameter memory block, which is the second input of the node, the second input of the heat transfer coefficient calculation block is the third input of the node, the fourth input of the heat transfer coefficient calculation block is the fourth input of the node and is connected to the second memory block input These parameters, the third input of which is connected to the output of the heat transfer coefficient calculation unit and is the output of the node, the fourth input of the parameter memory block is the fifth input of the node. thirty 40 45 Editor E. Papp Compiled by A.Sergeev Tehred I.Popovich Order 5923/7 Circulation 481 Subscription VNIIPI USSR State Committee for inventions and discoveries, 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, ul. Project, 4 Proofreader A.Ilyin