KR101482340B1 - Electric furnace and method for controlling position of electrode - Google Patents

Abstract

The present invention relates to an electrode rod position control method and an electric furnace using the same, and more particularly, to an electric furnace according to an embodiment of the present invention includes an electrode rod for generating an arc to heat molten steel stored in a furnace body, A lance for generating a foam, and a body vibration sensor for generating a body vibration signal by measuring a structure borne noise generated in the body, a height of the slag foam by using a body vibration signal, And the control unit may adjust the height of the end of the electrode rod to a height obtained by subtracting a predetermined value from the height of the calculated slag foam.

Description

BACKGROUND OF THE INVENTION Field of the Invention [0001] The present invention relates to an electric furnace,

The present invention relates to an electrode rod position control method and an electric furnace using the same, and more particularly, to an electrode rod position control method for controlling the position of an electrode rod according to a height of a slag foam and an electric furnace using the method.

Generally, in electric arc furnace operation, it is possible to maintain the slag layer thickness so as to protect the arc so that the arc generated in the electrode rod is not exposed to the atmosphere. Therefore, the heat transfer efficiency of the arc to the molten steel can be improved, and nitrogen can be prevented from flowing into the atmosphere. However, in the past, techniques have been developed to improve the slag foam height rather than accurately predict slag thickness.

That is, in order to increase the slag thickness, carbon and oxygen may be blown into the slag by using a lance, and the resulting slag layer may be increased in thickness using the foaming phenomenon. Here, the thickness of the slag layer can be referred to as the slag foam height.

On the other hand, the slag foam height can be predicted by observing the state of the slag flowing out to the slag gate. However, since the position of the molten steel bath surface is not known, the slag height flowing out to the slag gate has a problem that the accurate slag height can not be known.

It is also possible to predict the height of the slag foam by directly hearing the magnitude of the arc noise. However, since the magnitude of the arc noise at the time of forming the slag foam is relatively small, unlike the case of dissolving the scrap iron, the human auditory ability is not easy to distinguish arc noise from other noise in the factory. Further, since the magnitude of the arc noise experienced by the operator may differ depending on the psychological state of the operator, it is difficult to reliably determine the accuracy of the determined slag foam height. Therefore, there is a problem that it is impossible to accurately predict the height of the slag foam in the electric furnace operation in the conventional method.

The present invention provides an electrode rod position control method capable of adjusting the position of an electrode rod according to a height of a slag foam, and an electric furnace using the same.

According to an embodiment of the present invention, there is provided an arc welding apparatus including: an electrode rod for generating an arc to heat molten steel stored in a furnace body; A lance for supplying slag foam to the molten steel to generate a slag foam inside the slag; A body vibration sensor for measuring a structure borne noise generated in the body and generating a body vibration signal; And a control unit for calculating a height of the slag foam by using the body vibration signal and adjusting a height of the electrode according to a height of the slag foam, An electric furnace is provided for adjusting the height of the slag foam to a height minus a predetermined value.

Here, the control unit may calculate the height of the slag form corresponding to the body vibration signal using a database in which the height change of the slag foam according to the body vibration is learned by using the artificial intelligence network (Neural network).

According to an embodiment of the present invention, there is provided an arc welding apparatus including: an electrode rod for generating an arc to heat molten steel stored in a furnace body; A lance for supplying slag foam to the molten steel to generate a slag foam inside the slag; A body vibration sensor for measuring a structure borne noise generated in the body and generating a body vibration signal; And a control unit for calculating a height of the slag foam by using the body vibration signal and adjusting a height of the electrode according to the height of the slag foam, wherein the control unit controls the height change of the slag foam according to the vibration of the body, The database calculates a height of the slag form corresponding to the nozone vibration signal using a database learned using an artificial intelligence network, and the database includes a slag gate for discharging the slag generated in the electric furnace to the outside There is provided an electric furnace which generates a reference signal with respect to the height of the slag foam by using an image signal picked up and matches the change of the reference signal with the artificial intelligence network according to the body vibration.

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Here, the controller may adjust the height of the end of the electrode using a table table including a magnitude of an arc voltage for generating an arc in the electrode and a height of the end of the electrode corresponding to the magnitude of the arc voltage.

According to an embodiment of the present invention, there is provided a method of manufacturing an arc furnace, comprising: a molten steel heating step of generating an arc by an electrode rod to heat molten steel stored in the furnace body; A slag foam forming step of supplying an additive to the molten steel with a lance to form a slag foam in the furnace body; A vibration measuring step of measuring a vibration of the vibration body generated by the vibration body using the vibration body vibration sensor to generate a vibration body vibration signal; A height calculation step of calculating a height of the slag foam by using the body vibration signal; And controlling the height of the electrode according to the height of the calculated slag foam, wherein the step of controlling the electrode includes controlling a height of the end of the electrode by subtracting a predetermined value from a height of the calculated slag foam The height of the electrode is controlled by adjusting the height of the electrode.

Here, the height calculation step may calculate the height of the slag form corresponding to the body vibration signal using a database in which the height change of the slag foam according to the body vibration is learned by using the artificial intelligence network (Neural network) .

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In addition, the means for solving the above-mentioned problems are not all enumerating the features of the present invention. The various features of the present invention and the advantages and effects thereof will be more fully understood by reference to the following specific embodiments.

According to the electrode position control method and the electric furnace using the electrode pole position control method according to an embodiment of the present invention, the height of the slag foam produced in the molten steel production process of the electric furnace can be precisely measured.

In addition, since the height of the electrode can be controlled according to the measured height of the slag foam, the electrode can generate an arc inside the slag foam. Therefore, it is possible to improve the electric power efficiency due to the protection of the furnace body and the thermal effect, and to improve the quality of the molten steel by blocking contact with nitrogen in the atmosphere.

Further, since the height of the electrode rod can be controlled according to the height of the slag foam, it is possible to prevent undue waste of the sub-raw material when adding a sub-raw material to increase the power input.

1 is a block diagram showing an electric furnace according to an embodiment of the present invention.
2 is a graph showing a result of measuring the height of a slag foam according to an embodiment of the present invention.
3 is a flowchart showing a method of controlling an electrode position according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, in order that those skilled in the art can easily carry out the present invention. In the following detailed description of the preferred embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In the drawings, like reference numerals are used throughout the drawings.

In addition, in the entire specification, when a part is referred to as being 'connected' to another part, it may be referred to as 'indirectly connected' not only with 'directly connected' . Also, to "include" an element means that it may include other elements, rather than excluding other elements, unless specifically stated otherwise.

The electric furnace uses scrap or the like as a main raw material, and can produce molten steel by dissolving the scrap iron using an arc generated between an electrode rod of the electric furnace and scrap iron. Specifically, a process for producing molten steel in the electric furnace will be described. The process for producing molten steel in the electric furnace may include a first furnace, a first melting furnace, a second furnace furnace, a second melting furnace, have.

First, the scrap metal used as the main raw material in the electric furnace can be divided into primary and secondary and can be charged into the electric furnace. Once the primary charging is completed, electricity can be supplied to the electric furnace to dissolve the scrap metal, which is the main raw material. After the primary charging of the scrap metal is completed, the secondary charging is performed. It can dissolve. Here, calcium oxide (CaO), dolomite, and the like may be supplied into the electric furnace in the middle of the primary dissolver and the secondary dissolver.

After the secondary dissolver, a lance can be used to blow in the furnace, that is, oxygen and foaming material (carbon powder). Here, the oxygen supplied by the lance can induce a decarburization reaction in which carbon in the molten steel is reduced in the last stage of the secondary dissolver, in which the scrap is completely dissolved, and in the booster.

C (molten steel) + (1/2) O2 (gas) = CO (gas)

At this time, the CO gas generated by the decarburization reaction can be collected in the slag formed on the molten steel, and the slag can be formed more than the actual volume by the CO gas to form the slag foam. This phenomenon is referred to as a slag foaming phenomenon. When the thickness of the slag foam is actively increased, the arc of the electrode rod is stabilized and the heat loss of the molten steel is reduced, so that the power consumption can be reduced. Generally, the higher the height of the electrode, the higher the arc voltage is applied, and the higher the arc voltage is applied, the higher the power efficiency of the electrode can be. Accordingly, the position of the electrode can be adjusted so as to generate an arc after the electrode rod is elevated as high as possible within the slag foam.

However, in the past, the height of the slag foam was determined based on the shape of the slag discharged from the operator to the slag gate or the arc noise due to the arc generation. Therefore, the accuracy of the slag foam height is lowered, and each operator has a large variation, so that efficient operation can not be achieved.

However, according to the electric furnace according to the embodiment of the present invention, the height of the slag foam is accurately measured, and the height of the electrode is adjusted according to the height of the slag foam, so that it is possible to operate at a high arc voltage. Hereinafter, this will be described in detail with reference to Fig.

1 is a block diagram showing an electric furnace according to an embodiment of the present invention.

Referring to FIG. 1, an electric furnace according to an embodiment of the present invention may include an electrode rod 10, a lance 20, a body vibration sensor 30, and a controller 40.

The electrode rod 10 can generate an arc to heat the molten steel stored in the furnace body 1. The electrode rod 10 can form an arc between itself and the molten steel by using an arc voltage applied thereto, and can heat the molten steel using arc heat generated by the arc. As the distance between the electrode rod 10 and the molten steel increases, the arc voltage for generating the arc can be increased. As the arc voltage is increased, the power efficiency and the power factor can be improved. The height of the electrode rod 10 can be adjusted, and in particular, the height of the electrode rod 10 can be adjusted according to a position signal sig_h output from the control unit 40. In addition, the magnitude of the arc voltage of the electrode 10 may be controlled by the controller 40.

The lance 20 may provide the molten steel with an additive material to produce the slag foam S in the furnace body 1. The additive may include oxygen and a foaming agent (carbon powder), and the slag may be swollen by the additive. As described above, the decarbonation reaction can be induced by the oxygen supplied from the lance 20, and CO gas can be generated in the furnace body 1 by the decarburization reaction. Thereafter, when the CO gas is collected in the slag formed on the upper portion of the molten steel, the slag foam S can be formed while the volume of the slag is increased. Here, it is also possible to adjust the degree of formation of the slag foam S by adjusting the amount of the sub-raw material supplied by the lance 20. That is, if the formation of the slag foam S is insufficient after the height of the slag foam S is measured, the amount of the sub material may be added. If the formation of the slag foam S is excessive, The supply amount can be reduced.

The body vibration sensor 30 can measure the body vibration generated in the body 1 to generate the body vibration signal sig_vib. The arc of the electrode rod 10 can oscillate the furnace body 1, and the height of the slag foam S can be changed by the arc. Therefore, after the correlation between the vibration of the furnace body 1 and the height of the generated slag foam S can be grasped, the height of the slag foam S can be measured using the furnace vibration signal sig_vib Do. The body vibration signal sig_vib generated by the body vibration sensor 30 can be transmitted to the controller 40. [

The control unit 40 can calculate the height of the slag foam S using the nozone vibration signal sig_vib and adjust the height of the electrode 10 in accordance with the calculated height of the slag foam S . At this time, the controller 40 may output the position signal sig_h to the electrode 10 to adjust the height of the electrode 10.

First, the control unit 40 measures the height S of the slag foam according to the noble body vibration signal sig_vib using the database in which the correlation between the body vibration and the height of the slag foam S is stored can do.

The database may be obtained by learning the change in the height of the slag foam S according to the vibration of the furnace body using a neural network. In the database, the slag foam S corresponding to each furnace vibration The height may be stored. Accordingly, when the nozone vibration signal sig_vib is input to the controller 40, the controller 40 can output the height of the slug form S corresponding to the nozone vibration signal sig_vib.

Here, in order to obtain a correlation between the height of the slag foam S and the height of the slag foam S, information on the exact height of the slag foam S may be required to form a database containing the correlation. Therefore, the image signal for the slag gate can be acquired by capturing the slag gate, and the height information of the slag foam S can be extracted from the image signal. Conventionally, since the operator identifies the height of the slag foam S using the shape of the slag discharged from the slag gate, the image signal of the slag gate is analyzed to extract the slug form height information, It is possible to use a reference signal.

Thereafter, the correlation between the nominal vibration and the height of the slag foam S can be obtained using the reference signal and the nodular vibration signal sig_vib corresponding to the reference signal. At this time, the correlation between the noise vibration and the slag foam S can be obtained by using a plurality of samples, and the correlation between the noise vibration and the slag foam S is learned using the artificial intelligence network can do. That is, it is possible to empirically derive the correlation between the body vibration and the slag foam S and to make a database.

In addition, a power supply signal sig_pwr for supplying a voltage and a current to the electrode rod 10 may be input together with the nozone vibration signal sig_vib, and the nozone vibration signal sig_vib and the current supply signal sig_pwr And the height of the slag foam S may be calculated to construct the database. That is, the database can be formed in such a manner that the artificial intelligence network learns the change of the reference signal according to the change of the body vibration signal sig_vib and the power-on signal sig_pwr. Therefore, the control unit 40 can use the database to determine the height of the slag form according to the power-on signal sig_pwr and the body-vibration signal sig_vib.

FIG. 2 is a graph illustrating a height measurement result of a slag foam according to an embodiment of the present invention, wherein L1 is a height of the slag foam extracted through the image signal, L2 is a height of the slag foam, The height of the slag foam. As shown in FIG. 2, according to the height measurement of the slag foam according to an embodiment of the present invention, it is confirmed that the height of the slag foam can be measured in a manner similar to the height of the actual slag foam by the image signal have.

When the height of the slag foam S is calculated, the controller 40 can adjust the height of the electrode 10 by using the calculated height of the slag foam S. As described above, it is preferable that the electrode rod 10 discharges an arc in the slag foam S, and maximizes the distance between the electrode rod 10 and the molten steel. That is, the control unit 40 may adjust the height of the electrode so that the end of the electrode 10 has a height minus a predetermined value from the height of the calculated slag foam. Here, the end of the electrode 10 may refer to the lowermost end of the electrode 10 that generates electric current through the molten steel to generate an arc.

Specifically, the controller 40 limits the height of the calculated slag foam to the limit height of the end of the electrode 10 so that the electrode 10 is always positioned inside the slag foam S . It is also possible to limit the height of the calculated slag foam S by a predetermined value to the limit height of the end of the electrode 10. In this case, The position of the electrode rod 10 can be more stably controlled.

The arc voltage applied to the electrode rod 10 is proportional to the distance between the electrode rod 10 and the molten steel so that the arc height of the arc electrode 10 applied to the electrode 10 It is also possible to set the size. That is, after setting the limit voltage corresponding to the predetermined height limit for the electrode 10, it is possible to restrict the arc voltage of the limit voltage or more not to be applied to the electrode 10.

Although there is generally a linear relationship between the arc voltage and the height of the electrode 10, it is also possible to control the height of the electrode 10 using a table table for more precise position control. That is, a table table can be constructed by obtaining the correlation between the magnitude of the arc voltage and the height of the electrode 10 by using experimental data or the like in advance, and the threshold voltage corresponding to the threshold height can be obtained through the table Can be set. Therefore, it is possible to make the position of the electrode 10 follow the height of the slag foam by setting the limit voltage applied to the electrode 10 using the calculated height of the slag foam.

3 is a flowchart showing a method of controlling an electrode position according to an embodiment of the present invention.

3, the electrode position control method according to an embodiment of the present invention includes the steps of heating molten steel (S10), forming a slag foam (S20), measuring a vibration (S30), calculating a height (S40) And a control step S50.

Hereinafter, an electrode position control method according to an embodiment of the present invention will be described with reference to FIG.

In the molten steel heating step (S10), an arc is generated by the electrode rod, and molten steel stored in the furnace body can be heated. As described above, when molten steel is formed using an electric furnace, the molten steel can be produced through a process of primary charging, primary melting, secondary charging, secondary melting, The heating step S10 may correspond to the booster. That is, the scrap or the like already dissolved through the dissolving process or the like can be heated by using the electrode.

Subsequently, in the slag foam forming step (S20), a liquefied additive may be supplied to the molten steel, and the slag foam may be formed in the furnace body by the additive. The additive may include oxygen and a foaming material (carbon powder), and the slag foam may be formed by the CO gas generated by the decarburization reaction by the oxygen. The degree of formation of the slag foam may be controlled by an arc generated by the electrode.

When the slag foam is formed, the vibration measurement step S30 can measure the vibration of the rotor body using the rotor vibration sensor and generate the rotor vibration signal corresponding to the rotor vibration. The height of the slag foam may be varied by the arc generated by the electrode, and vibration of the furnace body may be generated by the arc of the electrode. Therefore, the height of the slag foam can be calculated by using the furnace vibration signal measured in the vibration measuring step S30.

In the height calculation step S40, the height of the slag foam can be calculated using the body vibration signal. Specifically, the height calculation step (S40) may calculate the height of the slag foam using a database storing the correlation between the height of the slag foam and the body vibration. Here, the database may be obtained by learning the change in the height of the slag foam according to the vibration of the furnace body using the artificial intelligence network, and the height of the slag foam corresponding to the vibration of the furnace body may be stored in the database. Therefore, when the nozone vibration signal is input, the height of the slag foam corresponding to the nozone vibration signal can be output.

When the height of the slag foam is calculated, the height of the electrode can be adjusted through an electrode rod control step (S50). As described above, it is advantageous in terms of electric power efficiency and power factor to keep the distance between the electrode rod and the molten steel at a maximum while generating an arc in the slab foam. Therefore, in the electrode electrode control step S50, the height of the electrode can be adjusted to have a height obtained by subtracting the terminal height of the electrode from the calculated height of the slag foam by a predetermined value. That is, in the electrode electrode control step (S50), the electrode can be positioned inside the slag foam and maintain a high arc voltage.

Here, since the arc voltage applied to the electrode is a magnitude of a voltage for generating an arc in the electrode, the arc voltage may become larger as the distance between the electrode and the molten steel increases. That is, the magnitude of the arc voltage and the height of the electrode rod are proportional to each other. Therefore, it is also possible to perform the position control of the electrode by setting the magnitude of the arc voltage corresponding to the height of the set electrode. At this time, it is also possible to perform the position control of the electrode using a table table including the magnitude of the arc voltage and the height of the corresponding electrode.

The present invention is not limited to the above-described embodiments and the accompanying drawings. 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 by the appended claims, .

1: Noche 10: Electrode
20: Lance 30: Void vibration sensor
40:
S10: heating the molten steel S20: forming the slag foam
S30: Vibration measurement step S40: Height calculation step
S50: Electrode control step

Claims (8)

An electrode for generating an arc to heat molten steel stored in the furnace body;
A lance for supplying slag foam to the molten steel to generate a slag foam inside the slag;
A body vibration sensor for measuring a structure borne noise generated in the body and generating a body vibration signal; And
And a controller for calculating a height of the slag foam by using the body vibration signal and adjusting a height of the electrode according to a height of the slag foam,
Wherein the controller adjusts the height of the end of the electrode to a height obtained by subtracting a predetermined value from a height of the calculated slag foam.
The apparatus of claim 1, wherein the control unit
An electric furnace for calculating a height of the slag form corresponding to the furnace vibration signal by using a database in which the height change of the slag foam according to the furnace body vibration is learned by using an artificial intelligence network.
An electrode for generating an arc to heat molten steel stored in the furnace body;
A lance for supplying slag foam to the molten steel to generate a slag foam inside the slag;
A body vibration sensor for measuring a structure borne noise generated in the body and generating a body vibration signal; And
And a controller for calculating a height of the slag foam by using the body vibration signal and adjusting a height of the electrode according to a height of the slag foam,
Wherein the control unit calculates a height of the slag form corresponding to the body vibration signal by using a database in which the height change of the slag foam according to the body vibration is learned by using the artificial intelligence network,
Wherein the database is configured to generate a reference signal for the height of the slag foam by using an image signal of an image of a slag gate for discharging the slag generated from the molten steel to the outside, An electric furnace formed by matching with an artificial intelligence network (Neural network).
delete The apparatus of claim 1, wherein the control unit
And adjusting a height of an end of the electrode using a table table including a magnitude of an arc voltage generating an arc in the electrode and a height of an end of the electrode corresponding to the magnitude of the arc voltage.
A molten steel heating step of generating an arc by an electrode rod to heat molten steel stored in the furnace body;
A slag foam forming step of supplying an additive to the molten steel with a lance to form a slag foam in the furnace body;
A vibration measuring step of measuring a vibration of the vibration body generated by the vibration body using the vibration body vibration sensor to generate a vibration body vibration signal;
A height calculation step of calculating a height of the slag foam by using the body vibration signal; And
And controlling the height of the electrode according to the calculated height of the slag foam,
Wherein the electrode electrode control step adjusts the electrode height to a height obtained by subtracting a terminal height of the electrode from a predetermined height of the calculated slag foam.
7. The method of claim 6, wherein the height calculation step
A height of the slag foam corresponding to the body vibration signal is calculated using a database in which the height change of the slag foam according to the body vibration is learned by using an artificial intelligence network.
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