RU2177847C1 - Rolling process control method - Google Patents

Abstract

FIELD: rolled stock production, namely controlling hot and(or) cold rolling processes. SUBSTANCE: method comprises steps of measuring parameters of strip in several points along rolling mill; selecting values of correction efforts acting upon actuating mechanisms; periodically measuring controlled parameters of strip, measuring angular velocity values of rolling rolls of stands and of rollers of roller tables; determining strip motion speed on base of measured angular velocity values; then on base of received results setting number of equal-sized portions of strip for further averaging at least of three values of measured controlled parameters in each strip portion and determining necessary correction efforts on base of averaged controlled parameters for each strip portion. Such method provides strict correspondence of controlled parameters to real volume of metal that is important for accuracy of controlling rolling process. EFFECT: enhanced accuracy of rolling process control method. 1 dwg, 2 tbl, 1 ex

Description

 The invention relates to rolling production and is intended to regulate the process of hot and / or cold rolling.

 A known method of regulating the rolling process, including changing the speed of rotation of the rolls depending on the presence of rolled material between them (Russian Patent 1665598, CL 21 21 37/00, 1995).

 The known method does not provide high accuracy control due to the fact that its implementation does not take into account the technological parameters of the rolling process.

 A known method of regulating the rolling process, including measuring the thickness of the rolled strip and introducing a corrective action on the actuators of the drive rolls when the thickness of the rolled strip deviates from the specified values (Patent of Russia 2125495, CL 21 V 37/00, 1999).

 The disadvantage of this method is the low accuracy of regulation, since they measure only one parameter and do not take into account the change in the speed of the rolled strip.

 The closest analogue to the claimed method is a method of regulating the rolling process, including measuring the technological parameters of the rolling process (rolled strip) with measuring instruments at several points along the length of the mill and the issuance of corrective actions on the actuators (Russian Patent 2078626, class B 21 V 37/00 , 1997).

Signs of the closest analogue, coinciding with the essential features of the invention:
1. Measurement of the controlled parameters of the rolled strip at several points along the length of the mill.

 2. The choice of corrective actions on the actuators.

 The known method does not provide high precision control of the rolling process, since in the process of measuring controlled technological parameters, their relationship with specific elements of the length of the rolled strip is not monitored. Therefore, when choosing corrective actions on actuators, it is not possible to accurately determine the time of application of corrective actions.

 The basis of the invention is the task of improving the method of regulating the rolling process, in which by tracking the relationship of the monitored parameters with specific elements of the length of the strip provides high accuracy control.

 The problem is solved in that in a method of regulating the rolling process, including measuring the controlled parameters of the rolled strip at several points along the length of the mill and the selection of corrective actions on the actuators, according to the invention, a discrete measurement of the controlled parameters is carried out, the angular speeds of the work rolls of the stands and roller conveyors are measured on the basis of measurements of angular velocities, a predetermined number of equal sections of the strip is isolated for subsequent averaging of at least three values and measured controlled parameters on each segment and determine the necessary corrective actions based on the averaged values of the controlled parameters.

 The measurement of the angular velocities of the work rolls of stands and rollers is necessary to highlight a given number of equal-sized segments of the rolled strip. Based on measurements of angular velocities, taking into account the diameters of the work rolls and rollers of the roller tables, the linear speed of the rolled strip is determined, for which the advancing and delay coefficients are introduced, depending on the assortment parameters and rolling modes.

 The allocation of a given number of equal-sized segments allows you to increase the reliability of determining the controlled parameters, because it allows you to track the relationship of the controlled parameters with specific elements of the strip length. Subsequent averaging of at least three values of the measured controlled parameters on each of the selected equal-sized segments also allows to increase the reliability of determining the controlled parameter due to the multiple measurements and averaging and to increase the accuracy of regulation. Moreover, if you average less than three measurement values of the controlled parameters, the reliability decreases, since random errors that occur in the measuring instruments significantly affect the measurement accuracy.

 Determination of the necessary corrective actions based on the averaged values of the controlled technological parameters allows you to get a strip with minimal deviations of the parameters from the set values.

 The essence of the proposed method is illustrated by the drawing, which conventionally shows a fragment of a rolling mill, consisting of two stands and a rolling table between them.

 A device illustrating the implementation of the proposed method contains a first stand in the form of a pair of work rolls 1, a second stand in the form of a second pair of work rolls 2 and a roller table located between them with rollers 3. The rolls and rollers are equipped with angular velocity sensors 4 associated with the computing unit 5, which can be made in the form of a personal computer equipped with appropriate software. Between the stands in the measuring position, a device 6 is installed, which provides the measurement of the controlled parameter. This can be a temperature meter (pyrometer), a width meter, a tape thickness meter, etc. The device 6 is also connected to a computing unit 5, the output of which is connected to a system 7 for collecting, storing and displaying information, the role of which can be played by a personal computer.

 The method is as follows.

 At the entrance of the rolling stock to the first stand and throughout the entire movement of the rolling stock in the rolling mill, from the sensors 4 of the angular velocity of the rolls of the working stands and rollers of the roller conveyors, information is received in the computing unit 5, based on which the unit determines the relative speed of the strip at any time and determines the moment of entry strip to the measuring position in which the device 6 for measuring the controlled parameter is located, after which it begins to record the information coming from it. In this case, each discrete measurement of the controlled parameter coming from the device 6 is fixed in combination with the measurement time. At the moment the strip exits from under the device 6, the recording of parameters stops and their processing begins. During data processing, for each recorded discrete measurement, the relative coordinate along the strip is calculated from the recorded speed of the strip and the measurement time. Then the entire length of the strip is divided into a given number of equal-sized segments, an analysis is carried out, to which segment does each discrete measurement belong? and measurements related to one segment are averaged.

 According to the results of measuring and averaging the values of the controlled parameters of the strip, the mill settings are adjusted accordingly directly during the rolling process, which significantly increases the accuracy of the rolling process regulation, ensuring its compliance with the specified final characteristics (permissible deviations in width, thickness, etc.).

 Example.

The proposed method of regulating the rolling process was carried out on a continuous broadband hot rolling mill. The method was used to control the installation of laminar cooling of a strip with a length of 900 m from steel grade 08YU before its winding into coils. The measured controlled parameter was the temperature of the strip after it exited the last stand of the finishing group of the mill stands. Based on the values of the strip temperature, the selection of corrective actions on the actuators of the laminar cooling installation was performed to obtain the winding temperature in the range of 600-620 ^o C.

 To measure the temperature of the strip after it exited the last stand of the finishing group of the mill stands, a pyrometer was used installed at the exit of the last stand at the beginning of the discharge roller table. The pyrometer performed discrete measurements of the strip temperature with a frequency of 10 times per second. The angular velocities of the work rolls of the last finishing stand and the rollers of the discharge roller table were measured by tachometers mounted on the drives of the last finishing stand and rollers of the roller table. The diameter of the work rolls of the last stand of the finishing group was 750 mm, and the diameter of the rollers of the discharge roller table was 350 mm. Based on measurements of angular velocities and taking into account the diameters of the rolls and rollers, the linear speed of the strip was determined, the values of which lay in the range of 6.5-11.2 m / s. 50 sections of 16 m each were allocated, and the period of passage of each section of the strip under the pyrometer was determined based on the linear speed of the strip. The selected number of segments is determined, on the one hand, by the speed of actuators, and, on the other hand, by the requirements for regulation accuracy. The measured discrete temperature values were averaged for each segment. The obtained temperature values were averaged for each segment. The data obtained are presented in table 1.

 The obtained average temperature values for each segment were used to determine the necessary corrective actions on the actuators in this case, to automatically turn on or off the sections of the laminar cooling unit during the passage of the strip through it.

 As can be seen from the table, the average temperature at 5 and 6 segments is significantly different from the average temperature of the remaining segments. If these sections are cooled in the same mode as the others, then the winding temperature of these two sections will go beyond the specified limits. In this regard, the corrective action was chosen in the form of the inclusion of one additional section of the laminar cooling installation during the passage of 5 and 6 segments through the scope of the additional section. Due to this, the temperature of the winding along the entire length of the strip, which is within the specified limits, is achieved. The obtained data on the temperature of the winding are presented in table 2.

 The proposed method provides high precision regulation, which leads to an increase in the quality of the finished product.

Claims (1)

 A method of regulating the rolling process, including measuring the controlled parameters of the rolled strip at several points along the length of the mill and selecting corrective actions on the actuators, characterized in that they carry out discrete measurement of the controlled parameters, measure the angular speeds of the work rolls of stands and roller conveyors, based on which the speed is determined the movement of the strip, based on the data obtained, a specified number of equal-sized segments of the strip is isolated for subsequent averaging not less than three values of the measured parameters controlled at every given interval and determine the required corrective action based on the average values of monitored parameters for a given segment.

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