KR101761144B1 - Method for Detecting Slag employed in Appliance for producing Iron - Google Patents

Method for Detecting Slag employed in Appliance for producing Iron Download PDF

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Publication number
KR101761144B1
KR101761144B1 KR1020160006245A KR20160006245A KR101761144B1 KR 101761144 B1 KR101761144 B1 KR 101761144B1 KR 1020160006245 A KR1020160006245 A KR 1020160006245A KR 20160006245 A KR20160006245 A KR 20160006245A KR 101761144 B1 KR101761144 B1 KR 101761144B1
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South Korea
Prior art keywords
molten steel
tundish
ladle
slag
vibration
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KR1020160006245A
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Korean (ko)
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이인석
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태인시스템주식회사
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D2/00—Arrangement of indicating or measuring devices, e.g. for temperature or viscosity of the fused mass
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10—Supplying or treating molten metal
    • B22D11/103—Distributing the molten metal, e.g. using runners, floats, distributors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H1/00—Measuring characteristics of vibrations in solids by using direct conduction to the detector
    • G01H1/12—Measuring characteristics of vibrations in solids by using direct conduction to the detector of longitudinal or not specified vibrations
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Acoustics & Sound (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geology (AREA)
  • Remote Sensing (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geophysics (AREA)
  • Continuous Casting (AREA)

Abstract

A ladle for receiving molten steel, a tundish for supplying molten steel from the ladle, a long nozzle provided between the ladle and the tundish to provide a supply path for the molten steel, a molten steel from the tundish , A first valve for controlling the supply of molten steel from the ladle to the tundish, and a second valve for controlling the supply of molten steel from the tundish to the mold A method for detecting a slag of molten steel supplied from a ladle to a tundish is disclosed. While the supply of molten steel from the ladle to the tundish through the long nozzle is controlled by controlling the first valve, the weight of the tundish is measured, and when the rate of increase in weight is decreased below a predetermined reference value, .

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method for detecting slag in a steel production facility,

More particularly, the present invention relates to a method for detecting slag in molten steel supplied from a ladle to a tundish.

1 is a view schematically showing a general steel production facility.

The steel production facility used in the steelworks includes ladles 10 and 20 that receive molten steel, a tundish 70 that receives molten steel from the ladles 10 and 20, ladders 10 and 20, A long nozzle 50 provided between the tundish 20 and the tundish 70 for providing a supply path for the molten steel and an opening and closing means for interrupting supply of the molten steel from the ladle to the tundish A slide gate 40 constituting the tundish 70 and a mold 90 for molding the molten steel discharged from the tundish 70 into a steel P as a final product.

Two ladles 10 and 20 are typically provided and one ladle 10 is supplied with molten steel to the tundish 70 while the other ladle 20 is refilled with molten steel Is performed. The slide gate 40 controls whether or not molten steel is supplied to the tundish 70 by closing or opening the lower outlet of the ladle 10 by the sliding drive of the valve. When the life of the long nozzle 50 is shortened, the fixing part 60 moves the long nozzle 50 out of the long nozzle 50, After the replacement, it returns to the position shown in FIG. The tundish 70 serves to buffer the supplied molten steel in the process of supplying the molten steel from the ladles 10 and 20 to the mold 90 and supply the molten steel to the mold 90 through the tundish 70. [ Closing operation of the stopper 80 that opens and closes the discharge port of the motor.

In this steel production facility, a slag (S) is layered on the molten steel (F) filled in the ladle (10). The slag S is composed of impurities other than iron in molten steel F, mainly limestone or the like. The slag S is partially introduced into the tundish 70 in the process of supplying molten steel so that the slag S is also thinned in the molten steel F in the tundish 70. [ The slag may have a pure function of preventing the oxidation of the molten steel F by forming a film on the molten steel F, but as a result, it is preferable that the slag is minimized in order to prevent deterioration of the quality of the steel P because it is an impurity. Particularly, the slag S in the tundish 70 acts as an impurity in the molten steel supplied to the mold 90. When the slag is excessive, the slag S at the end of the finally produced steel P, It may cause the phenomenon that the steel (P) explodes because it does not cool well when sprayed. Accordingly, various attempts have been made to minimize the slag S in the tundish 70 in particular.

It is very important to block the slag S flowing from the ladle 10 into the tundish 70 in order to minimize the slag S in the tundish 70. [ Since the slag S is formed in the upper layer in the ladle 10, most of the molten steel F is discharged during the molten steel discharging operation in the ladle 10 to capture the point at which the slag S starts to be discharged Control is required to shut off the discharge using the slide gate (40). If the slide gate 40 is blocked in advance to completely block the introduction of the slag S into the tundish 70, the molten steel remains in the ladle 10, If the slide gate 40 is blocked too late, the amount of the slag S is increased and the steel P is deteriorated in quality.

1 and 2 show an example of a conventional method for preventing the inflow of the slag S. As shown in Fig. The conventional slag detecting apparatus includes a coil 100 wound around a section between a ladle 10 and a long nozzle 50, a current detector (not shown) for detecting a current flowing through the coil 100, And a controller 120 for controlling the slide gate 40 in accordance with the detection result of the slide gate 40.

Fig. 3 is a view for explaining the operation principle of the slag detection device shown in Figs. 1 and 2. Fig. When a metal material with a high dielectric constant passes through an inner space in which a coil is wound, a current (i) is generated in the coil, and this current is proportional to the amount and speed of movement of the metal. Since the molten steel F is iron, when the molten steel F is discharged from the ladle 10 and passes through the internal space in which the coil 100 is wound, a current is generated in the coil 100, . When the discharge of the molten steel F from the ladle 10 is completed and the discharge of the slag S is started, the amount of the current induced in the coil 100 starts to sharply decrease since the slag S is mostly a limestone component . Therefore, the controller 120 determines that the slag S has been discharged from the time when the amount of the current induced in the coil 100 starts to decrease during the discharging operation of the molten steel F, And the discharge port of the ladle 10 is blocked by the slide gate 40. [ Thus, the slag S is prevented from flowing into the tundish 70.

However, such a conventional method has the following problems.

In the conventional method, the coils 100 must be installed in all the ladles 10 and 20. Therefore, when the ladle 10 is replaced with another ladle 10, it is necessary to perform the operation of detaching the coil 100 from the ladle 10 and then attaching the new ladle 10 to the new ladle 10 do.

In addition, since the conventional method requires connecting wires to the coil 100 and the controller 120, a cable and a cable connector 110 must be in between. Accordingly, when the first ladle 10 completes the molten steel discharging operation in the state shown in FIG. 1, the second ladle 20 filled with molten steel is moved toward the tundish 70, The coil 100 attached to the ladle 10 must be separated from the coupling 110 and the coil 100 of the second ladle 20 must be connected to the coupling 110 again. Therefore, it is necessary to repeat the operation of detaching the coil 100 from the connector 110 every time the ladle 10, 20 is alternately changed.

A new method for determining whether the material discharged from the ladle 10 is molten steel F or slag S has been proposed and solved by the inventors of the present invention. In the proposed method, unlike the conventional method, the vibration applied to the long nozzle 50 is detected, and the presence or absence of slag is checked based on the detected vibration. (This does not mean that this method is well known before the invention of the present invention.) The vibration sensing method has a difference in the degree of vibration occurrence in the case where the material passing through the long nozzle 50 is molten steel and in the case of slag As a method focused on the point, when the molten steel having a specific gravity as high as about 7.7 flows, there is a large difference in vibration generated in the long nozzle 50 as compared with when the slag S having a specific gravity of 1.3 or less flows.

In the case of the vibration sensing method, two methods of sensing the angular velocity change and the position change due to the vibration caused by the vibration can be assumed. However, the method of detecting the vibration is affected by the change of the own vibration during the operation of the steel production facility. For example, while the molten steel F is being supplied from the ladle 10 to the tundish 70 at a constant speed, the vibrations due to the ladle 10 itself are constant, 90, the total vibration decreases while the molten steel F is discharged from the tundish 70 to the mold 90, while the total vibration increases. Thus, if the time at which the slag S begins to be supplied from the ladle 10 to the tundish 70 occurs accidentally while the tundish 70 is stopping the molten steel discharge into the mold, The vibration is further reduced in a small state, and the change of the vibration detection amount becomes insignificant, which causes malfunction in slag detection by the vibration detection system.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for detecting slag in a material supplied from a ladle to a tundish by a vibration sensing method, And to provide a method for enabling detection of a stable slag discharge time point in spite of a variation amount of vibration due to an operating state.

According to another aspect of the present invention, there is provided a ladle comprising: a ladle for receiving molten steel; a tundish for receiving the molten steel from the ladle; A first valve means for interrupting the supply of the molten steel from the ladle to the tundish, and a second valve means for supplying the molten steel from the tundish to the tundish, And a second valve means for controlling the supply of the molten steel from the dish to the mold so as to detect a slag of the molten steel supplied to the tundish from the ladle, a) measuring the weight of the tundish while controlling supply of molten steel through the long nozzle to the tundish from the ladle by controlling the first valve means; b) detecting whether the increase rate of the weight of the tundish decreases during the step a); And c) determining that the slag has begun to be discharged from the ladle when the weight increase rate is decreased below a predetermined reference value in the step b).

(A-1) repeating the supply and stop of the molten steel from the tundish to the mold by controlling the second valve means during the a) step; a-2) detecting whether the remaining amount of the molten steel in the ladle has decreased to a predetermined value during the a-1) step; a-3) continuously controlling the second valve means to continuously supply the molten steel from the tundish to the mold when the remaining amount of the molten steel is detected to decrease within a predetermined amount in the step a-2) ; a-4) stopping the supply of the molten steel from the tundish to the mold by controlling the second valve means after performing the step a-3) for a predetermined time; a-5) detecting vibration applied to the long nozzle during the step a-4); And a-6) determining that the slag has begun to be discharged from the ladle if it is detected that the vibration resulting from the detection in the step a-5) is reduced to a predetermined degree or more.

The step c) may be performed during the step a-4).

According to the present invention, it is possible to accurately detect slag by detecting a time point at which slag is detected in a material supplied from a ladle to a tundish by a vibration sensing method. At this time, it is possible to detect a stable slag discharge time point despite the amount of change of vibration due to the operating state of the steel production equipment itself.

Furthermore, even when the vibration detection is inaccurate due to an external factor, accurate slag detection is possible without error by detecting the weight change amount of the tundish.

1 is a schematic view of a general steel production facility;
Fig. 2 is an enlarged view of the long nozzle portion of Fig. 1; Fig.
3 is a view for explaining the principle of the slag detection device employed in Fig.
4 is a view showing a basic configuration of a slag detection device according to the present invention.
5 is a view showing an example of the displacement sensing device of Fig.
6 is another embodiment of Fig.
7 is a view for explaining a control process of the slag detection method according to the present invention.
8 is a view for explaining a slag detection process based on the weight of a tundish in the slag detection method according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the present invention, the construction of the steel production facility except for the construction of the slag detection apparatus is the same as that of the conventional art described with reference to FIGS. Therefore, repetitive description thereof will be omitted and used as a constitution of the present invention, and the same constituent elements will be referred to using the same reference numerals.

In the description of the present invention, first, the configuration of the vibration sensing method as a premise for implementing the control method of the present invention will be described. In the following description, the displacement sensing device 200 has been illustrated and described. Alternatively, the vibration sensing device 200 may also detect vibration by sensing a change in the angular velocity of the long nozzle 50 due to vibration. It will be appreciated that various other vibration sensing methods may be employed.

FIG. 4 is a view showing a basic configuration of a slag detection apparatus according to the present invention, and is a view as compared to the conventional art of FIG. 2. FIG. The apparatus for detecting slag according to the present invention comprises a displacement sensing device (200) and a determination unit (300).

The displacement sensing device 200 is installed at one point of the fixing part 60 which fixes the position of the long nozzle 50. [ However, the displacement sensing device 200 may be installed in the long nozzle 50 itself or in another member to which the vibration of the long nozzle 50 is transmitted. The displacement sensing device 20 senses the displacement of the long nozzle 50 or the fixed portion 60 due to the vibration generated in the long nozzle 50 while the molten steel F passes through the long nozzle 50. [

The determination unit 300 determines whether the substance passing through the long nozzle 50 is slag S based on the displacement sensed by the displacement sensing device 200. When the slag S is determined, The slide gate 40 as the opening and closing means for controlling the molten steel discharge of the ladle 10 is controlled to stop the discharge from the ladle 10 as in the case of FIG.

5 is a view showing an example of the displacement sensing apparatus of FIG. The displacement sensing apparatus 200 includes a main body 210, an elastic member 220, a reference body 230, and a distance sensor 240.

The main body 210 is formed by bending an iron plate to form a frame, and is fixed to the fixing portion 60 by the U bolts 212. The elastic member 220 is fixed to the inner space of the main body 210 and shows an example in which the sponge 220 is introduced as an example of the elastic member 220 in this embodiment. The reference member 230 is manufactured in the form of a metal plate attached to the end of the elastic member 220 and supported by the elastic member 220. The distance sensor 240 is installed at a position facing the reference member 230 in the main body 210 and is spaced apart from the plate surface of the reference member 230 by a predetermined distance d. The distance sensor 240 senses the distance d relative to the reference body 230. As an example of the distance sensor 240, a capacitance sensor may be used that senses the distance based on the capacitance between the end of the distance sensor 240 and the plate surface of the reference member 230.

The operation of the displacement sensing apparatus having such a configuration is as follows.

The molten steel F passes through the long nozzle 50 while the molten steel F is discharged from the ladle 10 to the tundish 70. [ At this time, due to the flow of the molten steel F, vibration is generated in the long nozzle 50, and the vibration is transmitted to the fixing portion 60. When vibration occurs in the fixing part 60, the vibration is transmitted to the main body 210, which causes the main body 210 to be shaken and the vibration is also transmitted to the distance sensor 240 fixed to the main body 210. However, the reference member 230, which is elastically supported by the elastic member 220, is absorbed or attenuated by the elastic member 220 so that the reference member 230 can be maintained without changing its position or the distance sensor 240 Only a very small position change occurs. The distance d between the distance sensor 240 and the reference body 230 changes in proportion to the magnitude of the vibration and the distance sensor 240 changes the capacitance between the reference body 230 and the reference body 230 This magnitude of the distance change is sensed. This distance sensing process is also performed when the discharge of the molten steel F is completed and the discharging of the slag S is started.

However, the specific gravity of the molten steel (F) is as large as 7.7, and the specific gravity of the slag (S) is as small as about 1.3, and the specific gravity difference is six times. Therefore, the vibrations of the long nozzle 50 during the discharge of the slag S compared with the vibration of the long nozzle 50 during the discharge of the molten steel F are significantly reduced, and the vibration of the long nozzle 50 is detected by the distance sensor 240 Is also detected to have decreased correspondingly. Accordingly, when the displacement detected by the distance sensor 240 maintains a certain level and suddenly a displacement is reduced, this point is determined to be the start point of the slag S discharge, and the determination unit 300 determines this point, (40).

6 shows another embodiment of the present invention, in which an example in which a coil spring 222 is adopted as an elastic member is shown. 5, a sponge is employed as an elastic member, but a coil spring 222 is employed in this embodiment. Even when the coil spring 222 is used, the operation is the same as in the embodiment of Fig. 5 described above.

Further, in this embodiment, a guide 225 for guiding the moving direction of the reference member 230 to be limited in the longitudinal direction (vertical direction in the drawing) of the coil spring 222 is additionally provided. When only the coil spring 222 is installed, the vibration in the lateral direction may also be applied to the outside in the up-and-down direction. In order to prevent this, the guide 225 guides the shaking direction so that the reference member 230 is displaced only in the vertical direction.

The guide 225 is fixed to the main body 210 and is configured as a rod configured to penetrate the inside of the coil spring 222. Alternatively, ). ≪ / RTI >

7 is a view for explaining a control process of the slag detection method according to the present invention.

As described in the description of the prior art, during the operation of the steel production facility, the variation of the vibration during its operation differs depending on the state of operation. During the discharge of the molten steel F from the tundish 70 to the mold 90, The vibration is reduced and conversely, the total vibration increases while the discharge of molten steel F from the tundish 70 to the mold 90 is stopped. Thus, if the time at which the slag S begins to be supplied from the ladle 10 to the tundish 70 occurs accidentally while the tundish 70 is stopping the molten steel discharge into the mold, The vibration is further reduced in a small state, and the change of the vibration detection amount becomes insignificant, which causes malfunction in slag detection by the vibration detection system. Hereinafter, a slag detection process in which the control method of the present invention is introduced to solve such a problem will be described.

In the following description, the slide gate 40 for controlling the supply of molten steel F from the ladle 10 to the tundish 70 is the first valve, and the molten steel F from the tundish 70 to the mold 90 The stopper 80 for controlling the discharge is referred to as a second valve.

1, the first valve 40 is opened at time t1 and the supply of molten steel F from the ladle 10 to the tundish 70 is started. The supply of the molten steel F is continuously performed.

While the molten steel F is being supplied from the ladle 10 to the tundish 70 through the long nozzle 50, the second valve 80 is controlled to move the tundish 70 from the tundish 70 to the mold 90 The supply and interruption of molten steel are repeated. 7, the water level of the molten steel F in the tundish 70 starts to increase from the time t1 when the supply of the molten steel F is started. When the second valve 80 is opened at the time t11, The molten steel discharging from the tundish 70 to the mold 90 is started and the water level of the molten steel F in the tundish 70 is decreased and the second valve 80 is closed at the time t12, The water level of the molten steel F in the tundish 70 increases as the discharge of molten steel into the tundish 90 is stopped. In this manner, control is repeated such that the second valve 80 is opened at time t13 and time t15, and the second valve 80 is closed at time t14 and time t16 therebetween. The second valve 80 is controlled such that the amount of the molten steel F in the tundish 70 is changed within a predetermined range R so that the tundish 70 is molten into the mold 90 (F) supply is smoothly performed without interruption.

While the above process is repeated, the water level of the molten steel (F) in the ladle 10 is continuously detected. Although not shown in the drawings, the iron production facility is provided with a water level sensor for continuously checking the amount of molten steel F in the ladle 10, F).

It can be detected that the remaining amount of molten steel in the ladle 10 has decreased to a predetermined value when the discharge of the molten steel F has continued and the molten steel F has fallen below the predetermined level. The predetermined amount Q1 at this time is larger than the usual amount of the slag S generated in the ladle 10 so that the molten steel discharge from the ladle 10 progresses to some extent, The amount of molten steel F is set to an amount necessary to detect whether or not the slag S is discharged and may be set to about 15% of the total amount of the molten steel F before the start of discharging the molten steel F in the ladle 10, for example.

The second valve 80 stops the repeated opening and closing control and opens the second valve 80 for a predetermined period of time (for a period of time from t2 to t3) And continuously discharges the molten steel F from the mold 70 to the mold 90. Accordingly, the amount of molten steel in the tundish 70 continuously decreases from t2 to t3. Then, at time t3, the second valve 80 is closed, whereby the discharge of the molten steel F from the tundish 70 to the mold 90 is stopped, so that the molten steel F in the tundish 70 The water level starts to increase again. the occurrence of the phenomenon that the slag S starts to be discharged from the ladle 10 after the time t3 becomes imminent. Therefore, after time t3, the vibration applied to the long nozzle 50 is detected by using the displacement sensing device 200 or the like. Of course, the detection of vibration may be continuously performed in all the time zones from time t1.

the slag S starts to be discharged from the ladle 10 at a time t4 after the time t3 and the vibration is sharply reduced by the discharge of the ladle 10. [ Therefore, when it is detected that the vibration as a result of the vibration detection is reduced to a predetermined degree or more, it is determined that the slag S has started to be discharged from the ladle 10, and the necessary subsequent action, that is, And performs an action to block additional emissions from the ladle (10). Accordingly, the molten steel F is prevented from being supplied to the tundish 70.

The third table in Figure 7 shows the magnitude of the sensed vibration.

As described above, while the molten steel F is being supplied from the ladle 10 to the tundish 70, the second valve 80 is closed (from the tundish 70 to the mold 90) The total vibration is increased and the second valve 80 is opened (in a state where the molten steel F is discharged from the tundish 70 to the mold 90) .

However, in the present invention, by reducing the amount of the molten steel F in the tundish 70 from the time t2 to the time t3 so as to deviate from the predetermined range F (that is, , To prepare for the start of slag discharge from the ladle 10.

The amount of molten steel F in the tundish 70 is significantly reduced so that the molten steel F from the tundish 70 is continuously discharged for a considerable period of time from time t3, It is possible to ensure that the time interval during which the water level of molten steel F in the molten steel F is increased (i.e., the time interval during which the total vibration is increased) is maintained to be long. Therefore, the entire vibration is maintained for a considerable period of time from the time t3, and the time point t4 at which slag (S) discharge from the ladle 10 is started can be stably trapped in the time interval where the vibration is largely maintained . Therefore, when the vibration is reduced at time t4, the reduction in the state where the total vibration is large can be clearly detected.

If the molten steel discharge / interruption from the tundish 70 is continuously repeated at the same time intervals as in the conventional general control, if the total vibration amount is very high, for example, from t11 to t12, t113 to t14 and t15 to t16 The state of low detection is continuously repeated. In this case, the time point t4 at which the discharge of the slag (S) starts may occur in a state where the vibration is detected as low as the above-mentioned time period. However, according to the present invention, by sufficiently discharging the molten steel F in the tundish 70 during the time period t2 to t3, it is possible to increase the water level of the molten steel F in the tundish 70 after the time t3 Can be secured to a very large value, and thus a sudden decrease in vibration can be clearly discriminated.

Meanwhile, in the process as shown in FIG. 7, since the vibration is largely generated in the time period after the time point t3, the slag discharge time point (t4 time point) is captured using the principle that the vibration suddenly decreases at the time of slag discharge. However, when the slag discharge is started for some reason, the vibration may not decrease. There are many possible reasons for this phenomenon, for example, the influence of noise due to the external environment, the influence of vibration caused by the impact applied to the equipment due to the external work, and the slag itself And the influence of strong vibration in case. Therefore, the slag detection may not be accurately performed only by the process shown in Fig. 7, and the present invention proposes an additional process for precisely detecting the slag separately or in addition to such a process.

8 is a view for explaining a slag detection process based on the weight of a tundish in the slag detection method according to the present invention.

In the present invention, while the first valve 40 is controlled to supply the molten steel F from the ladle 20 to the tundish 70 through the long nozzle 50, the weight of the tundish 70 . Tundish 70 For weight measurement, a separate weight sensor (not shown) is added to the tundish 70.

The weight of the tundish 70 is changed in the same manner as the graph of the tundish molten steel water level shown in Fig. That is, as the amount of molten steel increases, the weight of the tundish 70 increases and as the amount of molten steel decreases, the weight of the tundish 70 decreases.

During this process, the water level of the molten steel continuously decreases in the section from the time t2 to the time t3 of FIG. 7, so that the weight of the tundish 70 is continuously decreased as shown in FIG. Then, as the supply of molten steel to the tundish 70 from the time t4 is resumed, the weight of the tundish 70 also increases steadily.

In this state, when the material supplied from the ladle 20 is changed to slag S rather than molten steel, the specific gravity of the slag S composed of limestone or the like is much lower than that of steel composed of iron, (Supply amount per unit time) is the same, the weight increase rate of the tundish 70 decreases. That is, as shown in FIG. 8, the slope of the weight increase graph from the time point at which the slag S starts to be supplied at the time t4 is sharply reduced compared to the slope of the weight increase graph from the time t3.

Using this principle, it is detected whether the increasing rate of the weight of the tundish 70 is decreasing. When the weight increasing rate is decreased to a predetermined reference value or less, the slag 20 is moved from the ladle 20 to the tundish 70, (S) is started to be discharged, and the supply of the slag (S) supplied to the tundish (70) is stopped by shutting off the first valve (40). Herein, the standard value is determined in consideration of the specific gravity of the molten steel and the specific gravity of the slag, and considering the normal supply speed of the molten steel supplied by the first valve 40 in the steel production facility to which the present invention is applied, It is determined differently.

The control by the weight detection of the tundish 70 according to the present invention may be performed in parallel with the process of FIG. 7, or may be performed independently of the process control of FIG.

According to the embodiment of the present invention, it is possible to stably and accurately detect slag even when an environment in which vibration detection is inaccurate due to an external factor or an internal factor occurs.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims and their equivalents. Of course, such modifications are within the scope of the claims.

Claims (3)

delete A tundish which receives the molten steel from the ladle; a long nozzle provided between the ladle and the tundish to provide a supply path of the molten steel; A first valve means for supplying the molten steel from the tundish to mold the steel, a first valve means for interrupting the supply of the molten steel from the ladle to the tundish, and a second valve means for supplying the molten steel from the tundish to the mold, And a second valve means for controlling the slag of the molten steel supplied from the ladle to the tundish,
a) measuring the weight of the tundish while controlling supply of molten steel through the long nozzle to the tundish from the ladle by controlling the first valve means;
b) detecting whether the increase rate of the weight of the tundish decreases during the step a); And
c) determining that the slag has begun to be discharged from the ladle if the weight increase rate is decreased to a predetermined reference value or less in the step b);
/ RTI >
During the step a)
a-1) repeating the supply and stop of the molten steel from the tundish to the mold by controlling the second valve means;
a-2) detecting whether the remaining amount of the molten steel in the ladle has decreased to a predetermined value during the step a-1);
a-3) continuously controlling the second valve means to continuously supply the molten steel from the tundish to the mold when the remaining amount of the molten steel is detected to decrease within a predetermined amount in the step a-2) ;
a-4) stopping the supply of the molten steel from the tundish to the mold by controlling the second valve means after performing the step a-3) for a predetermined time;
a-5) detecting vibration applied to the long nozzle during the step a-4); And
a-6) determining that the slag has begun to be discharged from the ladle when it is detected that the vibration resulting from the sensing in the step a-5) is reduced to a predetermined degree or more;
Further comprising the step of:
3. The method of claim 2,
Wherein the step c) is performed during the step a-4).
KR1020160006245A 2016-01-19 2016-01-19 Method for Detecting Slag employed in Appliance for producing Iron KR101761144B1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115138832A (en) * 2021-03-29 2022-10-04 宝山钢铁股份有限公司 Method for prolonging number of pure steel pouring furnaces based on molten steel weight information

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115138832A (en) * 2021-03-29 2022-10-04 宝山钢铁股份有限公司 Method for prolonging number of pure steel pouring furnaces based on molten steel weight information
CN115138832B (en) * 2021-03-29 2024-01-09 宝山钢铁股份有限公司 Method for prolonging number of pure steel pouring furnaces based on molten steel weight information

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