KR101320352B1 - Device for forecasting number of continuous-continuous casting on continuous casting process and method therefor - Google Patents

Abstract

The present invention relates to an apparatus for estimating the number of soft-dries during continuous casting and a method for predicting the number of soft-dwelling nozzles by predicting the blockage of the immersion nozzle through the fluctuation level of the surface of the mold. Collects the water level level measured by the water level level periodically and the water level level measured by the water level level sensor, and measures the total number of times measured during the set unit period and the reference range is set After calculating the hit rate by using the number of abnormalities, the cumulative hit rate is calculated by accumulating the calculated hit rate on the previous hit level, and using the calculated cumulative hit rate, the central processing unit for predicting the number of possible performances is provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for predicting an open performance of continuous casting,

More particularly, the present invention relates to an apparatus and method for predicting an open-casting number during continuous casting in which the degree of clogging of an immersion nozzle is predicted to predict an openable number.

The continuous casting machine is a machine that is produced in the steel making furnace, receives the molten steel transferred to the ladle by the tundish, and supplies it to the mold for the continuous casting machine to produce the cast steel of a certain size.

The continuous casting machine includes a ladle for storing molten steel, a playing mold for cooling the tundish and the molten steel discharged from the tundish for the first time to form a casting cast having a predetermined shape, and the casting cast formed in the mold connected to the mold. It includes a plurality of pinch rolls.

In other words, the molten steel tapping out of the ladle and tundish is formed as a cast piece having a predetermined width, thickness and shape in a mold and is transferred through a pinch roll, and the cast piece transferred through the pinch roll is cut by a cutter. It is made of slabs (Slab), Bloom (Bloom), Billet (Billet) and the like having a predetermined shape.

Related prior art is Korean Patent Publication No. 2004-50195 (published: 2004. 06. 16).

The present invention provides an apparatus and method for estimating the number of strands in continuous casting, which can predict the number of strands by predicting the blockage of the immersion nozzle through the amount of fluctuation in the surface of the mold.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above.

An apparatus for estimating a soft run number of the present invention for realizing the above object comprises: a water level sensor configured to be fixed on an upper side of a mold to periodically measure a water level according to the flow of molten steel in the mold; And collects the water level level measured by the water level level sensor, calculates the water level hit ratio using the total number of times measured during the set unit period, and the number of times the water level level is out of the set reference range, and is then calculated. And a central processor configured to calculate the cumulative hit ratio by accumulating the previous hit surface hit ratio and predict the number of consecutive performances using the calculated cumulative hit ratio.

The reference range may be set within a range of ± 3mm based on the molten steel level in the mold.

The hit rate can be obtained using a value obtained by dividing the number of abnormalities measured during a unit period by the total number of measurements.

The cumulative hit rate may be calculated by cumulatively multiplying the hit rate per unit period.

In order to achieve the above object, the soft-drain prediction method of the present invention comprises the steps of: periodically measuring the surface level of the molten steel in accordance with the flow of molten steel in the mold; Counting the total number of times of measurement measured during the unit period and the number of abnormalities in which each level is out of the set reference range when the set unit period elapses; Calculating a hit ratio based on the total number of measurements and the number of abnormalities counted above; And calculating the cumulative hit ratio by accumulating the calculated hit surface hit ratio on the previous hit surface hit ratio, and using the calculated cumulative hit ratio, predicting the number of consecutive performances.

The unit period may be set based on the casting time or the length of the cast pieces.

According to the present invention as described above, by predicting the degree of blockage of the immersion nozzle using the variation in the level of the surface of the mold in the mold, it is possible to predict and prevent the decrease in productivity due to the situation such as decrease in casting speed or stop casting cast There is an advantage.

1 is a conceptual diagram showing a continuous casting machine according to an embodiment of the present invention mainly on the flow of molten steel.
FIG. 2 is a view showing an apparatus for predicting a running performance according to an embodiment of the present invention.
3 is a view showing a decrease in peripheral speed according to the amount of fluctuations in the level of molten metal in the mold.
FIG. 4 is a flowchart illustrating a process of predicting an annual performance number according to an embodiment of the present invention.
5 and 6 are diagrams for explaining the cumulative hit ratio according to the amount of fluctuation of the surface of the mold.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like elements in the figures are denoted by the same reference numerals wherever possible. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

1 is a conceptual diagram showing a continuous casting machine according to an embodiment of the present invention mainly on the flow of molten steel.

Continuous casting is a casting process in which a molten metal is continuously cast into a bottomless mold while continuously drawing a steel ingot or steel ingot. Continuous casting is used to manufacture slabs, blooms and billets, which are mainly rolled materials, and long products of simple cross-section such as square, rectangle, and circle.

The shape of a continuous casting machine is classified into a vertical type and a vertical bending type. In Fig. 1, a vertical bending type is illustrated.

1, the continuous casting machine may include a ladle 10 and a tundish 20, a mold 30, a secondary cooling stand 60 and 65, a pinch roll 70, and a cutter 90 have.

The tundish 20 is a container that receives the molten metal from the ladle 10 and supplies the molten metal to the mold 30. In the tundish 20, the supply rate of the molten metal flowing into the mold 30 is controlled, the molten metal is distributed to each mold 30, the molten metal is stored, and the slag and the nonmetallic inclusions are separated.

The mold 30 is typically made of water-cooled copper and allows the molten steel to be primary cooled. The mold 30 has a pair of structurally opposed faces open to form a hollow portion for receiving molten steel. In the case of manufacturing the slab, the mold 30 includes a pair of barriers and a pair of end walls connecting the barriers. Here, the end wall has a smaller area than the barrier. The walls of the mold 30, mainly short walls, may be rotated away from or close to each other to have a certain level of taper. This taper is set to compensate for the shrinkage due to the solidification of the molten steel M in the mold 30. The degree of solidification of the molten steel (M) will vary depending on the carbon content, the type of powder (steel cold Vs slow cooling), casting speed and the like depending on the steel type.

The mold 30 is formed such that a solidified shell or a solidified shell 81 is formed so as to maintain the shape of the casting pluck pulled out from the mold 30 and to prevent the molten metal from being hardly outflowed from flowing out. . The water-cooling structure includes a method using a copper tube, a method of water-cooling the copper block, and a method of assembling a copper tube having a water-cooling groove.

The mold 30 is oscillated by the oscillator 40 to prevent the molten steel from sticking to the wall of the mold. Lubricant is used to reduce friction between the mold 30 and the solidification shell 81 and prevent burning during oscillation. As the lubricant, there is oil to be sprayed and powder added to the molten metal surface in the mold 30. The powder is added to the molten metal in the mold 30 to become slag, as well as lubrication of the mold 30 and the solidification shell 81, as well as to prevent oxidation and nitriding of the molten metal in the mold 30, to keep warm, and to the surface of the molten metal. It also performs the function of absorption of emerging nonmetallic inclusions. A powder feeder 50 is installed to feed the powder into the mold 30. The portion of the powder feeder 50 for discharging the powder is directed to the inlet of the mold 30.

The secondary cooling zones 60 and 65 further cool the molten steel primarily cooled in the mold 30. The primary cooled molten steel is directly cooled by the spraying means 65 for spraying water while being maintained by the support roll 60 so that the coagulation angle is not deformed. The solidification of the cast steel is mostly made by the secondary cooling.

The drawing device adopts a multidrive method using a pair of pinch rolls 70 and the like so as to pull out the cast pieces without slipping. The pinch roll 70 pulls the solidified tip of the molten steel in the casting direction, thereby allowing the molten steel passing through the mold 30 to continuously move in the casting direction.

The continuous casting machine configured as described above allows the molten steel M accommodated in the ladle 10 to flow into the tundish 20. For this flow, the ladle 10 is provided with a shroud nozzle 15 extending toward the tundish 20. The shroud nozzle 15 extends into the molten steel in the tundish 20 so that the molten steel M is not exposed to the air to be oxidized and nitrided.

The molten steel M in the tundish 20 is caused to flow into the mold 30 by the submerged entry nozzle 25 extending into the mold 30. The immersion nozzle 25 is disposed at the center of the mold 30 so that the flow of the molten steel M discharged from both the discharge ports of the immersion nozzle 25 can be made symmetrical. The start, the discharge speed and the interruption of the discharge of the molten steel M through the immersion nozzle 25 are determined by a stopper 21 provided on the tundish 20 in correspondence with the immersion nozzle 25. Specifically, the stopper 21 can be vertically moved along the same line as that of the immersion nozzle 25 so as to open and close the inlet of the immersion nozzle 25. The control of the flow of the molten steel M through the immersion nozzle 25 may use a slide gate method different from the stopper method. The slide gate controls the discharge flow rate of the molten steel (M) through the immersion nozzle (25) while the plate material slides horizontally in the tundish (20).

Molten steel (M) in the mold (30) starts to solidify from a portion in contact with the wall surface of the mold (30). This is because the periphery of the molten steel M is liable to lose heat by the water-cooled mold 30. The rear portion along the casting direction of the cast slab 80 is formed into a shape in which the non-solidified molten steel 82 is wrapped in the solidifying shell 81 by the method in which the peripheral portion first coagulates.

As the pinch roll 70 (FIG. 1) pulls the tip portion 83 of the completely cast solid cast piece 80, the unsolidified molten steel 82 moves together with the solidified shell 81 in the casting direction. The non-solidified molten steel (82) is cooled by the spraying means (65) for spraying the cooling water in the up-shifting process. This causes the thickness of the non-solidified molten steel (82) to gradually decrease in the cast steel (80). When the cast steel 80 reaches one point 85, the cast steel 80 is filled with the solidification shell 81 of the entire thickness. The solidification casting 80 having been solidified is cut to a predetermined size at the cutting point 91 and is divided into a slab P such as a slab or the like.

FIG. 2 is a diagram illustrating an apparatus for estimating a soft frequency according to an exemplary embodiment of the present invention, wherein the prediction apparatus 100 includes a water level sensor 110, a memory 120, a display unit 130, an input unit 140, and a central processing unit. It consists of 150.

The surface level sensor 110 is fixedly disposed on the upper side of the mold to periodically measure the surface level according to the flow of the surface of the molten steel in the mold. Here, the water level sensor 110 may be an eddy current type sensor 110 for measuring the level of the water level by analyzing the induced voltage caused by the eddy current of the molten steel according to the excitation of the high frequency current.

The memory 120 stores a unit cycle for measuring the level of the water level, a reference range for determining an abnormality of the level of the water level, a periodically measured level of the water level, a rate of hitting the surface, and a cumulative hit rate.

The display unit 130 may graphically display the tangential level, the tangential hit rate, and the accumulated hit rate collected through the tang level sensor 110.

The input unit 140 is configured to receive various operation commands or setting reference values from the outside and transmit them to the central processing unit 150.

The central processing unit 150 collects the water level level measured by the water level level sensor 110, and uses the total number of times measured during a set unit cycle and the water level level using the abnormal number outside the set reference range. The cumulative hit rate is calculated by accumulating the calculated hit surface hit ratio to the previous hit surface hit ratio, and using the calculated cumulative hit ratio, the number of consecutive performances is predicted.

The reference range may be set within a range of ± 3mm based on the molten steel level (Mold Level) in the mold. For example, when the molten steel level is 800 mm, the reference range may be set within a range of 797 to 803 mm.

In addition, the unit period may be set based on the casting time (for example, 10 minutes) or the length of the casting piece 80 (for example, 20 m). The central processing unit 150 may count the measurement time when the unit cycle is time, and when the unit cycle is the length of the cast steel 80, the central processor 150 may know the length of the cast steel 80.

As described above, in the present invention, the water level level measured by the water level sensor 110 is collected, and the number of abnormalities collected during the set unit period outside the set reference range is divided by the total number of times measured during the unit period. The hit rate is calculated, the cumulative hit rate is calculated by accumulating and multiplying the calculated hit level by the previous hit level, and then predicting the number of consecutive performances using the calculated hit rate.

In general, when the molten steel cleanliness is lowered, molten steel reoxidation occurs and the immersion nozzle is clogged. When the immersion nozzle is clogged, as shown in FIG. 3, the mold level is severely fluctuated, so that normal casting is difficult, and when the level is fluctuated, the casting speed is reduced or the cast casting is performed. Must be discontinued (part ⓐ).

Therefore, in order to prevent a productivity fall, it is necessary to predict the possibility of the continuous performance by the immersion nozzle clogging.

In the present invention, the degree of blockage of the immersion nozzle is predicted in advance by using the amount of fluctuation in the level of the surface of the mold, thereby preventing a decrease in productivity due to an unexpected decrease in casting speed or interruption of cast casting.

4 is a flowchart illustrating a process of predicting a number of years according to an embodiment of the present invention, and looks at it with reference to the accompanying drawings.

First, the central processing unit 150 calculates the peripheral speed at the time of continuous casting through the rotational speed of the pinch roll 70, and determines whether the calculated peripheral speed is the target peripheral speed. When the casting speed reaches the target pitch, the process of predicting the number of concertos starts.

When the casting speed reaches the target circumferential speed, the central processing unit 150 periodically collects the noodle level value according to the noodle flow of the molten steel in the mold from the noodle level sensor 110, and stores the collected noodle level value together with time information. It is sequentially stored at 120. Of course, the water level sensor 110 measures the water level in accordance with the flow of the molten steel in the mold periodically (for example, 1 second unit) and transmits it to the central processing unit 150 (S11 and S12).

When the casting speed reaches the target circumferential speed, the central processing unit 150 calculates the unit period stored in advance in the memory 120 to continuously determine whether the set unit period has elapsed (S13). If the unit cycle is the casting time, the central processing unit 150 will count the time, and if the unit cycle is the length (m) of the cast steel 80 will calculate the length of the cast steel 80 using the main speed. . The unit cycle may be about 1 to 10 minutes or about 1 to 20m.

3mm 이내의 범위로 설정될 수 있다.When the set unit cycle has elapsed, the central processing unit 150 counts the total number of measurements during the unit cycle collected in the memory 120 (S14). Subsequently, the central processing unit 150 compares each of the water level levels collected during the unit period with the set reference range, and counts the number of abnormalities in which the water level is out of the reference range (S15). The reference range above is based on the molten steel level in the mold

It can be set within a range of 3mm.

The central processing unit 150 calculates the hit rate HR _ML using the total number of measurements and the number of abnormalities counted as described above (S16). The method for calculating the hit rate HR _ML is shown in Equation 1 below.

Equation 1

Here, the total number of times of measurement is the number of times the level is measured during the unit cycle, and the number of abnormal times is the number of times the level of the measured level during the unit period is out of the reference range.

For example, the unit cycle is 10m (the length of the cast steel), 100 times (the total number of times of measurement) during the unit cycle is measured, and the number of times that each measured level is outside the reference range is 5 times (the number of abnormal times). If it were, the hit ratio would be 0.95 (1- (5/100)).

The hit surface hit rate thus obtained is stored in the memory 120 together with the time information (S17).

The central processing unit 150 obtains a hit rate per hit period per unit cycle and then checks whether there is a previous hit rate hit in the memory 120 (S18). If there is a previous hit surface hit rate stored in the memory 120, the central processing unit 150 calculates a cumulative hit rate by multiplying the calculated hit surface hit rate cumulatively by the previous hit surface hit rate (S19). For example, if the previous hit surface hit ratio is 0.98 and the current hit surface hit ratio is 0.95, the cumulative hit ratio will be 0.93 (0.98 × 0.95).

Subsequently, when the cumulative hit rate is calculated, the central processing unit 150 predicts the number of consecutive performances through the cumulative hit rate (S20). The number of possible performances based on the cumulative hit rate (HR _ACC ) is shown in Table 1 below.

Cumulative Hit Ratio (HR _ACC ) Can be played annually Explanation 0.95≤HR _ACC ≤1.00 + 2Heat 2Heat performance is possible 0.90≤HR _ACC <0.95 + 1Heat Available for 1Heat HR _ACC <0.90 0Heat (casting stopped) The next lecture stopped.

As shown in Table 1, if the cumulative hit ratio is 0.95 or more, the number of consecutive casts is at least + 2Heat.If the cumulative hit ratio is 0.90 or more and less than 0.95, the number of consecutive casts is + 1Heat.If the cumulative hit ratio is less than 0.90, only the current casting is performed. Note stops. Here, 1Heat means casting of molten steel contained in one ladle.

If the cumulative hit rate is more than 0.95, the number of possible performance stars is + 2Heat, where the number of performance stars is not a cumulative value, but means the number of performance stars from the current cumulative hit rate.

) 내에 있어 탕면 적중률이 대부분 '1'이 산출되었고, 그에 따라 누적 적중률도 대략 1.00으로 유지되는 나타났다. 이 경우에는 +2Heat의 연연주가 가능하다.In the case of FIG. 5, the surface level measured by the surface level sensor 110 is a reference range (for a predetermined time).

In most cases, the hit rate was calculated to be '1', and the cumulative hit rate was also maintained at approximately 1.00. In this case, you can play + 2Heat.

) 내에 존재하다가, 1.75시간[Hour]이 경과되면서는 ⓑ구간에서는 탕면 레벨값이 기준범위를 심하게 벗어나는 것을 알 수 있다. 이 경우에는 탕면 적중률이 대부분 0.9를 초과하지 않을 것이며, 그에 따라 누적 적중률도 0.90 미만으로 낮아지는 것으로 나타났다. 이 경우에는 다음 연연주가 불가능한 것으로 예측하고 주조를 중단하게 된다.However, in the case of FIG. 6, the level of the level of water measured by the level of water level sensor 110 is almost the reference range (for a predetermined time).

), While 1.75 hours [Hour] has elapsed, it can be seen that in the ⓑ section, the level of the water surface is significantly out of the reference range. In this case, the hit rate will not exceed 0.9 in most cases, and the cumulative hit rate will be lowered below 0.90. In this case, casting will be discontinued, predicting that the next performance will be impossible.

Therefore, in the present invention, by predicting the degree of blockage of the immersion nozzle by using the amount of change in the level of the surface of the mold, it is possible to predict and prevent the factor of productivity decrease, such as a decrease in casting speed or stop casting of the lead cast.

The above-described soft playability prediction method is not limited to the configuration and operation of the embodiments described above. The above embodiments may be configured such that various modifications may be made by selectively combining all or part of the embodiments.

10: Ladle 15: Shroud nozzle
20: Tundish 25: Immersion Nozzle
30: mold 31: left short side
35: right short side 40: mold oscillator
50: powder feeder 51: powder layer
52: liquid fluidized bed 53: lubricating layer
60: support roll 65: spray
70: pinch roll 80: performance cast
81: Solidification shell 82: Non-solidified molten steel
91: cutting point 100: control unit
100: prediction device 110: water level sensor
120: memory 150: central processing unit

Claims (10)

A water level sensor arranged at an upper side of the mold and periodically measuring a water level according to the flow of molten steel in the mold; And
Collecting the noodle level value measured by the noodle level sensor, using the total number of times measured during a set unit period and the number of times the noodle level value is out of the set reference range is calculated the hit rate of the noodle level calculated after And a central processor configured to calculate a cumulative hit ratio by multiplying the previous hit surface hit ratio by cumulative and using the calculated cumulative hit ratio, to predict the number of consecutive performances.
The method according to claim 1,
The reference range is a continuous number prediction device during continuous casting is set to within a range of ± 3mm on the basis of the molten steel level in the mold.
The method according to claim 1,
The hot water hit ratio ( HR _ML ) is a continuous number prediction device during continuous casting is calculated by the following formula.
Equation

Here, the total number of measurements is the number of times the level is measured during the unit period, and the abnormal number is the number of times the level of the measured level during the unit period is outside the standard range.
The method according to claim 1,
The cumulative hit rate is a continuous number prediction device during continuous casting is calculated by multiplying the hit rate per hit per unit cycle cumulatively.
Periodically measuring the surface level of the molten steel in accordance with the flow of the molten steel in the mold;
Counting the total number of times of measurement measured during the unit period and the number of abnormalities in which each level is out of the set reference range when the set unit period elapses;
Calculating a hit ratio based on the total number of measurements and the number of abnormalities counted above; And
Calculating the cumulative hit ratio by multiplying the calculated hit surface hit ratio by the previous hit surface hit ratio cumulatively, and using the calculated cumulative hit ratio, predicting the number of consecutive casts.
The method according to claim 5,
The unit cycle is a continuous number prediction method during continuous casting is set based on the casting time or the length of the cast pieces.
The method according to claim 5,
The reference range is a continuous number prediction method during continuous casting is set within a range of ± 3mm on the basis of the molten steel level in the mold.
The method according to claim 5,
The hot water hit ratio ( HR _ML ) is a method of predicting the number of years of continuous casting during continuous casting.
Equation

Here, the total number of measurements is the number of times the level is measured during the unit period, and the abnormal number is the number of times the level of the measured level during the unit period is outside the standard range.
The method according to claim 5,
The cumulative hit rate is a method of predicting the number of consecutive weeks when continuous casting is calculated by multiplying the hit rate per hit per unit cycle cumulatively.
The method according to claim 5,
If the cumulative hit rate is less than 0.9 in the continuous casting is a method of predicting the number of consecutive weeks during continuous casting.

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