KR20020016457A - Electrode immersion depth measurement apparatus of electro slag remelting process and its method - Google Patents

Abstract

PURPOSE: Provided is an apparatus and method for measuring a dipped depth of an electrode dipped under the surface of melt, whereby it is possible to prevent the lower end of the electrode from contacting to the inner wall of the mold and to prevent excess current, thereby completing a stable ESR process. CONSTITUTION: The apparatus for measuring a dipped depth of an electrode dipped under the surface of melt in a mold during an ESR process includes a first weight measuring device having a plurality of rod cells and disposed at the top of the electrode to measure a weight of the electrode; a second weight measuring device having a plurality of rod cells and disposed at the bottom of the mold to measure a weight of the mold; a height change measuring device to measure the change of height from the bottom of the mold to the upper end of the electrode; and a signal processing device to determine the dipped depth of the electrode by calculating data from the first and second weight measuring devices and the height change measuring device.

Description

Electrode immersion depth measurement apparatus of electro slag remelting process and its method

The present invention relates to an apparatus for measuring the depth of immersion of an electrode immersed under the molten surface of a slab present inside a mold in an ESR (Electro Slag Remelting) process, and in particular, comprising the weight of the electrode being melted and the molten steel and slag An apparatus and method for measuring the depth of an electrode immersed below the surface of a slab by measuring the weight of a mold.

Ingots are generally agglomerates of castings injected into a certain form, and are made by injecting molten metal into a mold or sand mold.

In order to make such a general ingot of special steel, secondary refining is performed to remove impurities contained in the ingot. ESR (Electro Slag Remelting) process uses the ingot to be refined as a consumed electrode to apply a high voltage and high current to form a slag layer, and re-dissolves the electrode with resistance heat of molten slag and re-cools it by water cooling. It is a secondary refining process that produces high purity steel by removing impurities of molten steel through the reaction.

1 is a schematic view showing an ESR apparatus for secondary refining according to the prior art.

As shown in FIG. 1, the ESR apparatus supports and supports a mold 5 through which cooling water circulates, an electrode 1 which is an ingot inserted into the mold 5, and an upper end of the electrode 1. An electrode holder (2), a guide column (4) standing in parallel with the electrode (1), and one end of the guide column (4) to move up and down along the longitudinal direction of the guide column (4), and at the other end of the electrode A support 3 to which the holder 2 is fixed, and a power supply 8 for supplying power to the electrode 1 and the mold 5.

The secondary refining process in this ESR system is as follows.

The electrode 1 is inserted into the mold 5. Then, powder and slag are placed between the electrode 1 and the mold 5 so that a current flows through the electrode 1 and the mold 5. As such, when current is applied to the electrode 1 and the mold 5 by the powder and slag, heat of resistance is generated in the powder and slag, and the resistance heat melts the powder and slag, and gradually the electrode 1 is also melted. . In this process, impurities contained in the electrode 1 escape from the molten steel by chemical reaction with the slag and are contained in the slag to float on top of the molten steel. Through this process, all of the electrodes 1 are melted and recooled the molten steel, thereby obtaining high purity steel.

On the other hand, during this refining process, the electrode 1 should always be submerged below the molten slag. Therefore, it is necessary to keep the electrode 1 soaked under the hot water surface of the molten slag while transferring the support 3 supporting the electrode 1 downward along the longitudinal direction of the guide column 4.

However, conventionally, there was no separate immersion detecting means for measuring the immersion depth of the electrode 1 immersed below the water surface inside the mold 5, and the weight of the electrode 1 and the voltage of the power applied to the electrode 1 And the data of the process variables such as the current and the experimental results were collected to calculate the melt rate and to control the falling rate of the electrode without considering the immersion depth of the electrode 1 locked to the set melt rate. This conventional electrode immersion depth control method does not take into account the actual immersion depth of the electrode, and focuses only on the control of the melt rate, and if it is wrong, the electrode and the bottom of the mold may contact each other, thereby causing an overcurrent supply. There is a problem that adversely affects normal operation.

The present invention is provided to solve the problems of the prior art as described above, by measuring the weight of the electrode and the weight of the molten electrode and measuring the position of the electrode to measure the immersion depth of the electrode immersed below the surface of the mold It is an object of the present invention to provide an apparatus and a method for measuring the immersion depth of an electrode.

1 is a schematic view showing an ESR device for secondary refining according to the prior art,

Figure 2 is an ESR device with an apparatus for measuring the immersion depth of the electrode according to an embodiment of the present invention,

FIG. 3 is a block diagram illustrating an operation relationship of an apparatus for measuring an immersion depth of an electrode illustrated in FIG. 2.

♠ Explanation of symbols on the main parts of the drawing ♠

1 electrode 2 electrode holder

3: support 4: guide

5: mold 8: power supply

110: first load cell 120: second load cell

130: displacement sensor 140: signal processor

According to the present invention for achieving the object as described above, in the electrode immersion depth measuring device for measuring the depth of the electrode immersed below the molten surface inside the mold in an electro slag remelting (ESR) process, installed in the upper end of the electrode First weighing means for measuring the weight of the electrode, second weighing means for measuring the weight of the mold installed at the bottom of the mold, and height displacement from the bottom of the mold to the top of the electrode. Displacement measuring means for measuring, and the value measured from the first weighing means, the second weighing means and the displacement measuring means to calculate the depth in which the electrode is immersed below the surface of the molten slag molten in the mold An electrode immersion depth measuring apparatus including a signal processor is provided.

In addition, the first weighing unit and the second weighing unit of the present invention are composed of a plurality of load cells, and calculates the weight values of the electrode and the mold by summing the weight values measured from each load cell.

In addition, the signal processor of the present invention calculates the length of the electrode in the dissolution process by using the weight of the electrode measured in the first weighing unit by the equation (2), measured in the second weighing unit Using the weight of the mold to calculate the length of the ingot to be refined through the equation (3), and using the height displacement signal input from the displacement measuring means through the equation (4) from the lower end of the molten electrode An electrode immersion depth measuring apparatus is provided, which calculates a height to and calculates a depth in which the dissolved electrode is immersed below the surface of the slag through Equation 5.

In addition, according to the present invention, in the electrode immersion depth measuring method for measuring the depth of the electrode immersed below the molten surface inside the mold in an electro slag remelting (ESR) process, measuring the weight of the electrode and the weight of the mold And calculating a length of the electrode using the weight of the electrode, calculating a length of an ingot growing in the mold using the weight of the mold, and starting from the bottom of the mold. Calculating the length of the electrode, and calculating the length of the electrode immersed below the surface of the mold by using the calculated length of the electrode, the length of the ingot, and the height from the bottom of the mold to the top of the electrode. Provided is an electrode immersion depth measuring method comprising a.

In addition, in the step of measuring the weight of the electrode and the weight of the mold of the present invention by summing the values measured by a plurality of load cells installed on the top of the electrode and a plurality of load cells installed on the bottom of the mold, respectively An electrode immersion depth measuring method for measuring the weight and the weight of the mold is provided.

In the following, with reference to the accompanying drawings, a preferred embodiment of the immersion depth measuring apparatus and method of the electrode immersed below the surface of the mold according to the present invention will be described in detail.

2 is an ESR apparatus having an electrode immersion depth measuring apparatus according to an embodiment of the present invention, and FIG. 3 is a block diagram showing an operation relationship of the apparatus for measuring immersion depth of an electrode shown in FIG. 2.

As shown in FIGS. 2 and 3, first and second load cells 110 and 120 are disposed on an upper portion of the electrode 1 and a lower surface of the mold 5, respectively, so that the weight of the mold 5 and the electrode 1 ) Is measured and output as an electrical signal. In addition, the support 3 is provided with a displacement sensor 130 to measure the height of the change depending on the vertical movement of the support 3 and outputs as an electrical signal.

The electrical signals output from the first and second load cells 110 and 120 and the displacement sensor 130 are input to the signal processor 140, and the first and second load cells 110 and 120 are received from the signal processor 140. Calculate the depth of the electrode 1 is immersed in the water surface through the appropriate calculation process of the electrical signal with the weight information and the electrical signal with the changed height information according to the movement of the electrode (1). This calculation is described in detail below.

Meanwhile, the second load cell 120 measuring the weight of the mold 5 and the first load cell 110 measuring the weight of the electrode 1 are each composed of one load cell or a plurality of load cells. In the case of a single load cell, two weight information output from each load cell, that is, weight information of the mold 5 and weight information of the electrode 1 are used, but the weight of the mold and the electrode is measured using a plurality of load cells. In this case, the measurement accuracy is greatly improved by distributing and measuring loads applied to a plurality of load cells.

Therefore, in the present invention, the first and second load cells 110 and 120 for measuring the weight of the electrode 1 and the weight of the mold 5 will be defined in an embodiment consisting of a plurality of load cells.

The operation method of the immersion depth measuring device of the electrode immersed below the molten surface of the mold configured as described above will be described in detail.

As shown in FIG. 3, a weight value of the electrode 1 detected by the plurality of first load cells 110 installed at the top of the electrode 1 is measured, and a plurality of agents installed at the bottom of the mold 5. The weight of the mold 5 detected by the two load cells 120 is measured, and the position change of the support 3 is measured by the displacement sensor 130.

The measured values in the first and second load cells 110 and 120 are summed up as shown in Equation 1, respectively (S1).

EV = CE1 + CE2 + ..... + CEn

EM = CM1 + CM2 + ..... + CMn

Here, EV is the electrode weight value, EM is the weight value of the mold, CE is the weight value of the electrode measured from the respective load cells constituting the first load cell, CM is each load cell constituting the second load cell Is the weight of the mold as measured from the above, and n is the number of each load cell.

As in Equation 1, the weights of the electrode 1 and the mold 5 are measured using the weight values measured in each of the first and second load cells 110 and 120.

Then, in order to measure the depth of the slag immersed in the molten slag, that is, the bottom surface of the molten iron in the following process, it is necessary to first obtain the parameters required by the signal processor 140. The parameter is calculated as follows.

First, the value EV0 of the first load cell 110 and the value MV1 of the second load cell 120 are measured while the electrode 1 is not inserted into the electrode holder 2, and the electrode 1 is measured. Before the insertion into the electrode holder 2, the length EH1 of the electrode 1 is measured, and the value EV1 of the first load cells 110 is measured after inserting it into the electrode holder 2. Then, the electrode 1 is raised as much as possible, and the displacement sensor 130 value DV1 at this time and the lower end of the mold 5 at this time are zero, and the height L1 up to the upper end of the electrode 1 is determined. Actually, Then, the electrode 1 is lowered as much as possible, and the displacement sensor 130 value DV0 at this time and the height L0 to the upper end surface of the electrode 1 are measured using the lower end of the mold 5 as a zero point. do.

Next, the value EV2 of the first load cells 110 and the value MV2 of the second load cells 120 are measured when the dissolution process of the electrode 1 is completed. After completion of the melting, the length EH2 of the remaining part of the electrode 1 and the length HM2 of the new ingot generated by solidifying the dissolved electrode 1 are measured.

The measured values are parameters required by the signal processor 140, and the depths of the electrodes 1 immersed below the floor are calculated using these parameters.

Equation 2 below is a formula for calculating the length EH of the electrode 1 in the dissolution process using the parameters and the values of the first load cells 110 (S2).

EH = (EH1-EH2) / {(EV1-EV0)-(EV2-EV0)} × {EV- (EV2-EV0)} + EH2

Here, EV is the value of the first load cell, EH is the length of the electrode calculated by the signal processor 140 from the EV value, EV0 is the value of the first load cell without the electrode inserted in the electrode holder, EV1 is the value of the first load cell in the pre-melt state after inserting the electrode into the electrode holder, EH1 is the length of the electrode in the pre-melt state, EV2 is the value of the first load cell in the post-melt state after inserting the electrode in the electrode holder EH2 is the length of the electrode after dissolution.

In addition, the growth length of the growing ingot during the melting process is calculated as in Equation 3 (S3).

MH = MH2 / (MV2-MV1) × MV

Here, MV is the value of the second load cell, MH is the length of the grown ingot calculated by the signal processor 140 from the MV value, MV1 is the value of the second load cell without inserting the electrode before melting, MV2 is the value of the second load cell with the ingot in the mold after melting, and MH2 is the growth length of the ingot after melting.

Next, the height from the value of the displacement sensor 130 measured during the dissolution process to the upper end of the electrode 1 in the direct direction with zero as the lower end of the mold 5 is calculated as in Equation 4 (S4).

L = (L1-L0) / (DV1-DV0) × (DV-DV0) + L0

Where DV is the displacement sensor value, L is the height from the DV value to the upper end of the electrode, with the lower end of the mold calculated by the signal processor as zero, and DV0 is inserted into the electrode holder and lowered as far as possible. Is the displacement sensor value, L0 is the height from the bottom of the mold to the top of the electrode, and DV1 is the displacement sensor value when the electrode is inserted into the electrode holder and ascended up as much as possible, and L1 is DV1. In this case, it is the height to the upper end of the electrode with the lower end of the mold zero.

The depth of the electrode 1 is immersed below the water surface using the length of the electrode 1, the length of the ingot and the height information of the electrode 1 calculated using the above equations (2), (3), (4). It is calculated through the equation (5) (S5).

H = (EH-MH) -L

As described above, the apparatus for measuring the immersion depth of the electrode of the present invention measures the weight of the electrode, the weight of the mold containing the refined steel, and the displacement value of the support for supporting the electrode, and uses the previously set variables and the like below. Immersion depth of the immersed electrode can be calculated by

As described in detail above, the apparatus and the method for measuring the immersion depth of the electrode immersed below the molten surface of the mold of the present invention by measuring the immersion depth of the electrode during the refining process to contact the bottom of the electrode and the inner surface of the mold to flow overcurrent It has the advantage of being able to perform stable ESR process by preventing it.

Although the technical concept of the apparatus and method for immersion depth measurement of the electrode immersed below the molten surface of the mold of the present invention has been described together with the accompanying drawings, the present invention has been described by way of example only. It is not limited. In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

Claims (5)

In the electrode immersion depth measuring device for measuring the depth of the electrode immersed below the water surface in the mold in the electro slag remelting (ESR) process, A first weighing means installed at an upper end of the electrode to measure a weight of the electrode; A second weight measuring means installed at a lower end of the mold to measure the weight of the mold; Displacement measuring means for measuring a height displacement from a lower end of the mold to an upper end of the electrode; And a signal processor configured to calculate a value measured from the first weighing means, the second weighing means, and the displacement measuring means to measure a depth at which the electrode is immersed below the molten surface of the slag melted in the mold. Electrode immersion depth measuring device. The method of claim 1, The first weighing unit and the second weighing unit is composed of a plurality of load cells, the electrode immersion depth measuring apparatus, characterized in that to calculate the weight value of the electrode and the mold by summing the weight value measured from each load cell. The method according to claim 1 or 2, The signal processor calculates the length of the electrode in the dissolution process using Equation 1 using the weight of the electrode measured by the first weighing unit, and uses the weight of the mold measured by the second weighing unit. Calculating the length of the ingot refined through Equation 2, and using the height displacement signal input from the displacement measuring means to calculate the height from the bottom of the mold to the top of the dissolved electrode through Equation 3, The electrode immersion depth measuring apparatus, characterized in that to calculate the depth immersed below the molten surface of the slag through the dissolved electrode 4 through. Equation 1 EH = (EH1-EH2) / {(EV1-EV0)-(EV2-EV0)} × {EV- (EV2-EV0)} + EH2 Here, EH is the length of the electrode, EV is the value of the first weighing means, EV0 is the value of the first weighing means without inserting the electrode in the electrode holder holding the electrode, and EV1 is the electrode Insert the electrode into the holder and the value of the first weighing means in the pre-dissolved state, EH1 is the length of the electrode in the pre-dissolved state, and EV2 is the value of the first weighing means in the post-dissolved state after inserting the electrode into the electrode holder. Value, EH2 is the length of the electrode after dissolution Equation 2 MH = MH2 / (MV2-MV1) × MV Here, MV is the value of the second weighing means, MH is the length of the ingot, MV1 is the value of the second weighing means without the electrode inserted before melting, and MV2 is the ingot in the mold after melting. The value of the second weighing means in the present state, and MH2 is the growth length of the ingot after dissolution. Expression 3 L = (L1-L0) / (DV1-DV0) × (DV-DV0) + L0 Where DV is the displacement sensor value, L is the height from the DV value to the upper end of the electrode with the lower end of the mold calculated by the signal processor as zero, and DV0 is inserted into the electrode holder and lowered as far as possible. Is the displacement sensor value, L0 is the height from the bottom of the mold to the top of the electrode, and DV1 is the displacement sensor value when the electrode is inserted into the electrode holder and ascended up as much as possible, and L1 is DV1. In this case, it is the height to the upper end of the electrode with the lower end of the mold zero. Equation 4 H = (EH-MH) -L Where H is the immersion depth of the electrode, EH is the length of the electrode, MH is the length of the ingot, and L is the height from the bottom of the mold to the top of the electrode. In the electrode immersion depth measuring method for measuring the depth of the electrode immersed below the molten surface in the mold in an electro slag remelting (ESR) process, Measuring the weight of the electrode and the weight of the mold; Calculating a length of the electrode using the weight of the electrode; Calculating a length of an ingot growing in the mold using the weight of the mold; Obtaining a height from a lower end of the mold to an upper end of the electrode; And using the calculated length of the electrode, the length of the ingot, and the height from the lower end of the mold to the upper end of the electrode, calculating the length of the electrode immersed below the surface of the mold. Immersion depth measurement method. The method of claim 1, In the measuring of the weight of the electrode and the weight of the mold, the weights of the electrode and the weight of the mold may be calculated by summing the values measured by the plurality of load cells installed at the top of the electrode and the plurality of load cells installed at the bottom of the mold. Electrode immersion depth measuring method characterized by measuring the weight.