JPH02207957A - Device for controlling level of molten steel in casting mold - Google Patents

Abstract

PURPOSE:To control a molten steel surface level always in a specified position by determining the deviation between the molten steel surface and a previously set molten steel surface level and adjusting the rate of injecting the molten steel from a tundish to a casting mold and the rate of drawing a steel ingot by the integrated value of the deviation. CONSTITUTION:The molten steel in the tundish 11 is poured into the casting mold 13 for continuous casting by a sliding nozzle 12 and is continuously drawn out as the steel ingot by a drawing roller 14. A level detector 15 for the molten steel surface in the casting mold is provided near the casting mold 13 in this case and is connected to a controller 16. The level value of the molten steel surface in the casting mold is previously set in the controller 16 and the deviation from the molten steel surface level by the level detector 15 is determined and is integrated by an integrating circuit in the controller 16. The rate of pouring from the sliding nozzle 12 into the casting mold and the drawing rate of the steel ingot in the drawing roller 14 by a driving device 17 are controlled by the integrated value thereof, by which the molten steel surface level in the casting mold 13 is maintained in the specified set position.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an in-mold molten steel level control device used in a continuous casting machine.

(Prior Art) In a continuous casting machine, molten steel (molten metal) is poured into a mold from a ladle through a tundish, and slabs are continuously drawn from the mold while cooling the mold. In this type of continuous casting machine, if the molten metal level in the mold is not maintained within a specified range, it will not only have a negative effect on the quality of the slab, but also cause the molten metal to overflow from the mold and cause a serious accident. be.

For this reason, continuous casting machines are equipped with a level detector that detects the level of the molten metal in the mold, and based on the level detected by this level detector, the amount of molten metal poured from the tundish into the mold is adjusted, and the amount of molten metal poured from the mold is adjusted. Controls the amount of slab pulled out.

Conventionally, when controlling the molten metal level in the mold, the above-mentioned molten metal amount and slab withdrawal amount are controlled based on the deviation between the detected molten metal level and the set molten metal level.

(Problems to be Solved by the Invention) Generally, when the molten metal in the ladle runs out, it is replaced with a ladle filled with molten metal. During this replacement work, the continuous casting machine is not stopped and the molten metal remaining in the tundish is poured into the mold.

However, during so-called normal casting, in which the molten metal is poured from the ladle into the mold via the tundish, and during so-called unsteady casting, when the molten metal remaining in the tundish is poured into the mold when the ladle is replaced, the control amount of the molten metal and the slab withdrawal are The control amount is different. In other words, when determining the control amount from the deviation between the detected level and the set scene level, the difference between normal casting and unsteady pouring is
The amount of molten metal poured into the mold is different for the same control amount (substantially the sensitivity of the control device is different).

For this reason, conventionally, the sensitivity of the control device has been set at an intermediate level between the normal casting time and the emergency steady state, so that it can be applied to both the normal casting time and the unsteady time.

However, as mentioned above, since the sensitivity is set between normal pouring and unsteady pouring, the scene level fluctuates greatly, especially during unsteady pouring, and it is difficult to control the level to the set level. be.

That is, there is a problem that sufficient control accuracy cannot be obtained.

An object of the present invention is to provide a control device that can provide sufficient control accuracy during normal casting and during unsteady operation.

(Means for Solving the Problems) According to the present invention, it is used in a continuous casting machine that includes a mold, pours molten steel into the mold, and continuously pulls out slabs, and detects and detects the level of molten steel in the mold. It has a molten steel level detector that sends out a level signal, and an adjusting means that calculates a deviation between the detected level signal and a preset molten steel level setting value, and sends out a molten steel level adjustment signal based on the deviation. In the in-mold molten steel level control device, the amount of molten steel poured into the mold is adjusted based on a molten steel level adjustment signal, and the amount of the slab withdrawn is controlled based on the molten steel level adjustment signal, wherein the adjusting means is an integrating means for integrating the deviation, a proportional element means for outputting the molten steel level adjustment signal based on the output of the integrating means, and a proportional element means for receiving the deviation and corresponding to the magnitude of the deviation. There is obtained an in-mold molten steel level control device characterized by having a setting means for changing the proportional amount linearly.

(Function) In the present invention, the setting means changes the proportional amount of the proportional element means in accordance with the magnitude of the deviation between the detected molten metal level signal from the molten steel level detector and the preset molten metal level setting value. let For example, if the deviation is small (during normal casting), increase the proportional amount. In other words, the sensitivity is weakened. On the other hand, if the deviation is large (unsteady), the proportional amount is reduced.

In other words, increase the sensitivity.

In this way, since the sensitivity of the adjustment means is changed according to the deviation between the detected molten metal level signal and the molten metal level setting value,
The molten metal surface level can be controlled with high precision during normal casting and during unsteady casting.

(Example) The present invention will be explained below with reference to Examples.

First, the configuration of a continuous casting machine will be outlined with reference to FIG.

A sliding nozzle 12 is connected to the ladle 11 via a tundish (not shown).

A mold is located below the sliding nozzle 12.
14 are arranged. Molten metal is poured from a sliding nozzle 12 into a mold 13, and while being cooled within the mold 13, it is gradually drawn out as a slab by a drawing roller 14.

A molten metal level detector 15 for detecting the molten metal level of the mold 13 is arranged near the mold 13, and this molten metal level detector 15 is connected to a controller 16. This controller 16 determines the deviation between a preset molten metal surface level setting value and the molten metal surface level detected by the molten metal surface level detector 15, and outputs an elution level adjustment signal in accordance with this deviation. Then, the amount of molten metal from the sliding nozzle 12 is adjusted based on this molten metal level adjustment signal. On the other hand, the molten metal level adjustment signal is
R control device) 17, and the drive device 17 controls the amount of drive of the drawing roller 14 based on this molten metal level adjustment signal.

Here, the controller 16 will be explained in detail with reference to FIG.

Detected molten metal surface level value (pv) and molten metal surface level setting value (S
V) is input to the subtracter 16a, where (PV-SV
) is calculated to find the deviation.

This deviation is integrated by the integrating circuit 16b and output as an integrated value. Further, this deviation is input to the function setting device 16c.

As shown in FIG. 3, the function setting device 16c is preset with a function in which the horizontal axis is the deviation and the vertical axis is the proportional amount setting value, and the proportional amount setting value decreases as the deviation becomes thicker. , outputs a proportional amount set value (amplification factor) corresponding to the deviation input to the function setter 16c, and provides it to the proportional amplifier 16d.Also, when adding a differential operation to the PV value, a differentiator circuit 16e is used. .

The signal from the proportional amplifier 16d is used as a molten metal level adjustment signal, and as described above, the amount of molten metal from the sliding nozzle 12 is adjusted by this molten metal level adjustment signal. Further, this molten metal surface level adjustment signal is sent to the driving device 17, and the driving device 17 controls the driving amount of the drawing roller 14 based on this molten metal surface level adjustment signal.

In this way, since the amplification factor of the amplifier 16d is changed depending on the deviation between the detected molten metal level value (pv) and the molten metal level setting value, the controller Since the sensitivity of 16 is changed, it is possible to precisely control the set level of the molten metal during normal casting and during unsteady casting.

(Effects of the Invention) As explained above, in the present invention, the proportional amount of the #hairdressing step is changed according to the deviation between the detected molten metal level value and the molten metal level setting value. Since the sensitivity of the molten metal is changed, the molten metal surface level can be controlled accurately during normal casting and during unsteady casting.

Figure 1

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining a continuous casting machine to which the present invention is applied, Fig. 2 is a diagram for explaining the controller shown in Fig. 1, and Fig. 3 is a diagram for explaining the function setting device shown in Fig. 2. FIG. 11... Ladle, 12... Sliding nozzle, 1
3... Mold, 14... Pulling roller, 15.
... Molten metal level detector, 16... Controller, 17...
・Drive device. Figure 3

Claims (1)

[Claims] 1. A molten steel level detector that is used in a continuous casting machine that is equipped with a mold, pours molten steel into the mold, and continuously pulls out slabs, and that detects the molten steel level in the mold and sends out a detection level signal; and an adjusting means for determining a deviation between the level signal and a preset molten steel level setting value and sending out a molten steel level adjustment signal based on the deviation, and the molten steel is poured into the mold based on the molten steel level adjustment signal. In the in-mold molten steel level control device that adjusts the amount of molten steel and controls the amount of the slab withdrawn based on the molten steel level adjustment signal, the adjusting means includes an integrating means for integrating the deviation, and the integrating means. a proportional element means for outputting the molten steel level adjustment signal based on the output of the molten steel level adjustment signal, and a setting means for receiving the deviation and changing the proportional amount of the proportional element means in a broken line in accordance with the magnitude of the deviation. Features an in-mold molten steel level control device.