JPS608901B2 - Continuous casting mold level control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an in-mold scene level stabilization control device in continuous casting.

When manufacturing slabs by continuous casting, it is desirable to properly manage and maintain the level of the molten metal in the mold.

There are various causes of fluctuations in the level of the hot water inside the mold, but conventionally, relatively small level fluctuations are mainly controlled by changing the opening of the tundish nozzle, and large level fluctuations are mainly controlled by pinch rolls. This problem was addressed by changing the slab drawing speed. FIG. 1 is a diagram showing the above-mentioned sub-chassis device. As seen in the figure, the hot water level bell in the mold 1 is detected by a hot water level bell meter, and this detected value is used to detect the hot water level bell in the mold 1. The servo 3 is controlled by the dish nozzle controller LC1 (dead band is small).
The tundish nozzle 5 such as a sliding nozzle provided with the tundish nozzle 41 is controlled through the tundish nozzle 41, and the pinch roller 7 is controlled via the motor control device 6 by the pinch roller drive motor controller LC2 (large uncontrolled zone).
By controlling the speed of the motor M that drives the mold, the level of the hot water in the mold is kept constant.

However, the conventional device as described above has the following drawbacks. That is, there were cases where the tundish nozzle controller and the pinch roll drive motor controller interfered with each other.
From the viewpoint of the quality of slabs produced by continuous rust formation, control by changing the opening degree of the tundish nozzle is desirable, but when there are large fluctuations in the scratch surface, response speed becomes an issue. On the other hand, changing the drawing speed in steps is not preferable because it causes large fluctuations in the melt level. While the dummy bar is being pulled out, the pinch roll slips, which often causes large fluctuations in the hot water level. Since the settings of PID control coefficients and the like are manual and fixed, there is little adaptability to changes in mold size, sliding nozzle size, etc. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a continuous casting mold water leveling bell control device that can overcome the drawbacks of the conventional devices as described above.

The device of the present invention is an improvement on the conventional device described above, and includes a plurality of tundish nozzle control controllers,
Optimizing each PID coefficient etc. with respect to the nature of the fluctuations that may occur, and at the same time automatically switching each according to the detected nature of the fluctuations that occur or according to a predetermined sequence.

By detecting the drawing speed and applying feed forward control to the tundish nozzle control system based on that value, both control systems are organically engaged, and various variables such as PID coefficients used in each control system. It is characterized in that it is automatically changed by an automatic control constant setting device in accordance with changes in mold size, sliding nozzle diameter, etc. from time to time. FIG. 2 is a block diagram showing an embodiment of the mold water level bell control device according to the present invention.

In the figures, the same numbers as in FIG. 1 indicate the same parts. In FIG. 2, in addition to the device shown in FIG. 1, there is a switch 9, a motor speed detection device G, a feed forward control controller FF, a tundish nozzle opening controller LC3 for when the dummy bar is pulled out, an addition point 10, and various adjustments. A metering control constant automatic setting device 11, etc. is provided, and as can be seen from the figure, L
CI and LC3 are mutually coupled in parallel and selectively connected to one summing point by a switch 9. Further, the FF controls the servo device 3 via the addition point 10 based on the motor speed detection signal from G. The switch 8 automatically switches the control system depending on the magnitude of the deviation. These will roughly work as follows. That is, when the deviation of the hot water level bell from the reference value is small, the switch 8 is turned to LCI or LC3 to utilize the control of the tundish nozzle, and if the deviation becomes large due to some disturbance, the deviation is Switch 8 is automatically retracted toward LC2 until it becomes smaller, and the withdrawal speed is 0.
control by degree. The drawing speed is constantly detected and feed forward control is performed for the tundish nozzle control. While the dummy bar is being pulled out, the controller is controlled by the LC3, which has a PID coefficient set to sufficiently absorb large fluctuations in the hot water level due to slipping of the dummy bar, and during normal slab withdrawal, the normal PID coefficient is set. The switch 9 automatically operates so as to be controlled by the LCI. The constant automatic setting device 11 sets the PID coefficient and feedforward coefficient 0 that are optimal for the mold size and sliding nozzle diameter.
Set the number automatically. By using the device as described above, fluctuations in the level of the melt in the mold during continuous casting are significantly reduced, and the quality of continuously cast slabs is improved.
Since the hot water leveling bell control has been completely automated, which was previously impossible, there is also significant labor savings.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the secondary boiler level bell control device;
FIG. 2 is a block diagram showing a scene level control device according to the present invention. 1: Mold, 2: Hot water level detection device, 3: Servo control device, 4: Tandish, 5: Sliding nozzle, 6
: Motor speed control device, 7: Pinch roll, 8, 9: Switch, 10: Addition point, 1 unit 1: Constant automatic setting device,
LC1, LC2, LC3: Controller, M: Motor, G: Motor speed detection device, FF: Feedforward controller. Figure lFigure 2

Claims (1)

[Claims] 1. A mold level detection device, a tundish nozzle opening control device consisting of a tundish nozzle control servo device and a plurality of parallel-connected controllers for the servo device, a pinch roller drive motor, and A drawing speed control device comprising a motor control device and a controller for the motor control device, and a detection signal from the level detection device being selectively and automatically sent to the tundish nozzle opening control device or the drawing speed control device. a switch for selectively and automatically connecting the plurality of servo device controllers to a servo device for controlling a tundish nozzle;
a feedforward control device comprising a device that detects the speed of the motor and a feedforward controller that further controls the servo device using the detection signal; and a controller for the plurality of servo devices and a motor control device. A continuous casting mold surface level control device comprising a device controller and a device for automatically setting each constant of a feed forward controller.