JPH05302111A - Slag flowing-out and method for predicting slopping in converter - Google Patents

Abstract

(57) [Summary] [Purpose] Sloping is performed with little influence of disturbance, no time required for detection and analysis, no damage to the equipment required for detection, and no need for large-scale equipment modification. Predict. [Structure] A pair of a transmission coil 2 and a reception coil 3 which are opposed to each other with a slug 7 in between are installed in the vicinity of a tap hole 1 of a converter, and are generated between the transmission coil 2 and the reception coil 3. Measure the induced voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slag outflow detector and a converter sloping prediction method using the same.

[0002]

BACKGROUND OF THE INVENTION Slopping is a phenomenon in which slag and molten steel in a furnace are suddenly jetted out of a furnace during blowing of a converter. That is, it is a phenomenon that tends to occur when the slag layer in the middle stage of blowing is formed up to the height near the furnace opening by the CO gas generated from the steel bath. In particular, when soft blow or a large amount of iron oxide-based auxiliary material is added, FeO in the slag increases, and a CO reaction occurs explosively at the slag-molten steel interface.

The slopping disturbs the molten steel composition, reduces the yield of steel output, and causes various problems such as an increase in refining time, a reduction in OG gas recovery rate, a reduction in working environment, and damage to peripheral equipment. Therefore, it is necessary to prevent the occurrence of sloping by recognizing the slag foaming condition in the middle stage of blowing of the converter in real time and appropriately correcting the converter operating condition at the optimum timing. Therefore, various converter sloping prediction methods have been conventionally proposed.

(I) Japanese Unexamined Patent Publication No. 54-33790 discloses a method of estimating the slag height from changes in the frequency and intensity of sound in the furnace during blowing, and in Japanese Unexamined Patent Publication No. 58-48615. A method for predicting the occurrence of sloping from the change in the furnace surface temperature, and a method for estimating the slag height from the change in the vibration generated by the lance or the furnace body are proposed in JP-A-54-114414. Has been done. However, since all of these methods indirectly measure slag height from other surrogate properties,
There is a problem that the influence of disturbance is large and the measurement accuracy is not high.

(Ii) Japanese Unexamined Patent Publication No. 54-114414 proposes a method of estimating the slag height by measuring the amount or composition of exhaust gas generated during blowing, but it is not suitable for analysis and analysis of exhaust gas. It takes some time, so it is difficult to apply it in reality.

(Iii) Japanese Unexamined Patent Publication No. 57-140812 proposes a method of projecting a microwave from the upper part of the furnace mouth toward the inside of the furnace and estimating the slag height from the reflected wave. The microwave sensor that needs to be installed above the mouth is easily damaged by the frame.

(Iv) Japanese Unexamined Patent Publication No. 60-228928 discloses a method in which a through hole is provided in a side wall of a furnace and a photodetector is installed in the through hole, and a color signal is measured to detect occurrence of sloping. However, since it requires a large-scale converter remodeling such as the installation of through holes, it is hard to say that this is a desirable method.

In recent years, there have been proposed some methods of predicting sloping by imaging the tap hole of the converter and its vicinity and processing the captured image. For example, in Japanese Laid-Open Patent Publication No. 1-15311, an image pickup device provided facing a taphole of a converter takes an image of the taphole and its vicinity, and the taken image is a monitor of a furnace condition display device. Is displayed and observed, and the signal from the image pickup device is input to an arithmetic device through an image processing device for preprocessing, where the luminance of the tap hole of the converter or its temporal change is quantitatively obtained.
There has been proposed a method of predicting the occurrence of sloping by inputting this value into an alarm device and issuing an alarm from the alarm device when the value falls within a range where sloping may occur.

[0009]

However, the method proposed by Japanese Patent Laid-Open No. 1-15311 is premised on the use of an image pickup device, and therefore dust and dust existing between the image pickup device and the tap hole If the lens of the image pickup device becomes dirty due to smoke or the like, it causes a change in the amount of light, and there is a problem that the detection accuracy is extremely reduced.

Further, there is a problem that the field of view of the image pickup device is changed due to the vibration of the building so that the image pickup cannot be performed or the image pickup device is easily damaged.

The object of the present invention is to solve the problems of the prior art, to reduce the influence of disturbances, to reduce the time required for detection and analysis, to prevent damage to the equipment required for detection, and to further increase An object of the present invention is to provide a slag outflow detector that does not require large-scale facility modification and a converter sloping prediction method using the same.

[0012]

Means for Solving the Problems As a result of various studies to solve the above problems, the present inventor has found that the outflow phenomenon of the mixed metal slag from the tap hole of the tap hole of the converter is sloping. Considering this as a sign, by detecting the outflow of mixed metal slag from the tap hole of the converter by installing a pair of transmitter coil and receiver coil so as to sandwich the tap hole, it is possible to solve the above problems. Based on the findings, the present invention was completed.

Here, the gist of the present invention is that a pair of a transmission coil and a reception coil, which are installed to face each other with an outflow portion of a slag mixed with metal in between, and between the transmission coil and the reception coil. It is a slag outflow detector characterized by comprising a measuring device of an induced voltage.

From another aspect, the transmission coil and the reception coil of the above-mentioned slag outflow detector are installed so as to face each other at a position sandwiching a tapping hole of a tapping port of a converter, and the transmission coil and the receiving coil are disposed. It is a converter sloping prediction method characterized by predicting the occurrence of sloping by measuring an induced voltage generated between them.

[0015]

The present invention will be described in detail below with reference to the accompanying drawings together with its effects. FIG. 1 is an explanatory diagram showing an example of a slag outflow detector according to the present invention installed near a tap hole 1 of a converter. FIG. 1 (a) is an enlarged view of the vicinity of the tap port 1. 2B is a longitudinal sectional view shown in FIG. 3B, and FIG. 3B is a sectional view taken along line AA in FIG.

In FIG. 1, a pair of transmitter coil 2 and receiver coil 3 are installed to face each other with a steel tapping hole 1'of the converter, which is the outflow portion of the slag 7, interposed therebetween, and an alternating current is passed through the transmitter coil 2. As a result, an electromagnetic field 6 is formed between the receiving coil 3 and the receiving coil 3. The transmitter coil 2 and the receiver coil 3 may be installed directly on the iron shell 4 or may be embedded in the brick 5 inside the iron shell 4.

In the present invention, the transmitter coil 2,
The receiving coil 3 may be a known one and is not limited to a particular one. Further, the shapes and installation positions of the tap hole 1 and tap hole 1 ', and the kind of the brick 5 are not limited in the present invention. Further, although not shown in FIG. 1,
Cables 13 and 14 connect the measuring devices for the induced voltage generated between the transmitting coil and the receiving coil.

FIG. 2 is an explanatory view showing a structural example of the entire apparatus for carrying out the converter slopping prediction method according to the present invention. In FIG. 2, the slag outflow detector according to the present invention shown in FIG. 1 (only the transmitting coil 2 and the receiving coil 3 are shown in FIG. 2) is installed near the tap hole 1 of the converter 8. Hereinafter, the converter slopping prediction method according to the present invention will be described with reference to FIGS. 1 and 2.

A slag 7 containing a mixture of metal, which has entered the inside of the tap hole 1'by slag foaming during converter blowing.
However, when the electromagnetic field 6 formed between the transmission coil 2 and the reception coil 3 is crossed, the magnetic permeability between the transmission coil 2 and the reception coil 3 changes. The change in the induced voltage detected by this change is amplified by the preamplifier 10 connected through the terminal box 9, and the control panel 12 outputs an output waveform.

In the present invention, this waveform, particularly the height of the wave (the magnitude of the induced voltage), is used to directly detect the invasion state of the slag 7 into the tapped hole 1'and prevent the sloping of the converter 8. Predict. After predicting the sloping, a signal is output to the operation panel 11 in the converter operation room to issue an alarm to the operator. Therefore, according to the present invention, since the occurrence of sloping can be predicted with certainty, it is possible to change the operating conditions of the converter before the occurrence of sloping, and to easily cope with sloping.

Further, according to the present invention, the transmitter coil and the receiver coil may be installed at the tap hole of the converter, and the measuring device for measuring the change in the induced voltage between them may be installed. It is small, does not require time for detection and analysis, does not damage the equipment required for detection, and can be performed without requiring large-scale facility modification. Further, the present invention will be described in detail with reference to Examples, but this is an example of the present invention and the present invention is not limited thereto.

[0022]

[Examples] With the molten steel composition and operating conditions shown in Table 1, FIG.
And the converter blowing was performed using the apparatus of the structure shown in FIG. The conditions for applying the current to the transmission coil 2 were set as shown in Table 2.

[0023]

[Table 1]

[0024]

[Table 2]

During blowing of about 50 heats, a change in induced voltage of about 10% as shown in FIG. 3 was observed. Those that exceeded a preset alarm level (induced voltage: 2.5V) were predicted as sloping, and the correspondence with the actual occurrence of sloping was investigated. The results are shown in Table 3.

[0026]

[Table 3]

As is clear from Table 3, according to the present invention, it was possible to predict the occurrence of sloping with an extremely high probability. Moreover, neither the transmitting coil nor the receiving coil was damaged at all, and sloping prediction of at least 5000 heats or more was possible.

[0028]

As described in detail above, according to the present invention, it is possible to perform sloping prediction with high accuracy without requiring time for detection and analysis and without requiring large-scale facility modification. At the same time, it has become possible to predict sloping over a long period without maintenance.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a state in which an example of a slag outflow detector according to the present invention is installed in the vicinity of a tap hole 1 of a converter,
1A is an enlarged vertical sectional view showing the vicinity of the tap hole 1, and FIG. 1B is a sectional view showing a cross section taken along the line AA in FIG. 1A.

FIG. 2 is an explanatory diagram showing a configuration example of the entire apparatus for carrying out the converter slopping prediction method according to the present invention.

FIG. 3 is a graph showing changes with time of induced voltage in Examples.

[Explanation of symbols]

 1: Steel tap hole 1 ': Steel tap hole 2: Transmission coil 3: Reception coil 4: Iron coil 5: Bricks 6: Electromagnetic field 7: Slag 8: Converter 9: Terminal box 10: Preamplifier 11: Operation panel 12: Control panel 13: Cable 14: Cable

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshio Sato No.3 Hikari, Oshima, Kashima-machi, Kashima-gun, Ibaraki Prefecture Sumitomo Metal Industries, Ltd. Kashima Steel Works

Claims (2)

[Claims] 1. A pair of transmitting coils and receiving coils, which are installed so as to face each other with an outflow portion of slag mixed with metal in between, and a measuring device of an induced voltage between the transmitting coils and the receiving coils. A slag outflow detector characterized by. 2. The transmission coil and the reception coil of the slag outflow detector according to claim 1 are installed so as to face each other at a position sandwiching a tapping hole of a tapping port of a converter, and between the transmission coil and the receiving coil. A converter sloping prediction method characterized by predicting the occurrence of sloping by measuring the induced voltage generated.