KR20040024021A - Apparatus for reducing amount of electrode used - Google Patents

Abstract

PURPOSE: A device for reducing consumption amount of electrode rod is provided to prevent the electrode rod from being oxidized by the atmosphere by preventing clogging of nozzle of cooling water ring, thereby improving cooling efficiency and prevent deterioration of productivity by preventing electric spark generated by skull stuck to center piece. CONSTITUTION: In an electrode rod consumption amount reducing device for reducing consumption amount of electrode rod(56) by injecting cooling water onto the electrode rod through nozzle of cooling water ring(12), the electrode rod consumption amount reducing device comprises an injection ring(14) which is installed at a lower part of the cooling water ring, and on which a nozzle is formed so that nitrogen is injected in a central direction of the electrode rod, wherein the injection ring is formed in such a manner that the nozzle is inclined downward to 45 to 75 degrees of an angle.

Description

Apparatus for reducing amount of electrode used}

The present invention relates to an electrode consumption reduction device for reducing the consumption of the electrode used in the electric furnace, and more particularly to the injection of nitrogen into the cooling water ring for spraying the cooling water to cool the electrode to prevent the nozzle from clogging and uniform the cooling water The present invention relates to a device for reducing electrode consumption, which reduces the consumption of electrodes by improving the cooling efficiency.

In general, as shown in FIG. 1, scrap metal, which is a raw material, is introduced into the furnace 50 using a bucket, and scrap metal injected into the furnace 50 is applied to the arc heat generated by the electrode 56. Is dissolved by

In this way, various secondary raw materials are added to refine the molten steel in the process of melting the scrap metal.

Here, the inside of the electric furnace is supplied with oxygen through the lance in order to promote the combustion of the blowing gas and the like oxidized component risk is maintained.

In addition, the supplied oxygen is directly injected into the scrap metal mass to crush the scraps of iron and directly into the molten steel to decarburize and heat up the molten steel.

On the other hand, the oxygen introduced into the electric furnace causes a chemical reaction with the surface of the electrode made of carbon to increase the required amount of the electrode.

In addition, as the temperature is increased, as shown in FIG. 5, as the temperature is increased, the rate of oxidation consumption of the electrode increases.

In addition, when the temperature of the electrode is 550 ℃ to 750 ℃ reaction rate is related to the temperature as the rate step, when 800 ℃ or more, diffusion rate is related to the rate of the atmosphere gas as the rate rate step, the consumption rate of the electrode increases as the surface area increases Increases.

Therefore, in order to prevent oxidation of the electrode rod by the chemical reaction, the electrode consumption of about 5% to 10% could be reduced by punching the cooling water by making a hole inside the annular pipe around the top of the electrode.

However, in this case, when cooling water is injected to the electrode to reduce the consumption of the electrode, the dust generated by the hot gas in the furnace is ejected into the gap generated between the center piece of the loop located in the hearth and the electrode, and the cooling water ring. Is attached to the nozzle.

As such, the dust attached to the nozzle of the cooling water ring is combined with the surrounding water and fixed to the nozzle of the cooling water ring to close the nozzle, thereby reducing the amount of cold water injected into the graphite electrode, thereby increasing the temperature of the electrode and increasing the surface of the electrode. The exposure to the outside air oxidizes, increasing the consumption of graphite electrodes.

In addition, when the cooling water is injected into the electrode to reduce the consumption of the electrode, the cooling water injected through the nozzle flows down to the surface of the electrode to cool the surface of the electrode, and part of it is converted into steam by the high temperature electrode to evaporate, and the rest is When the electric furnace is tilted, it is separated from the electrode surface by its own weight and falls around the center piece.

At this time, since the cooling water dropped around the center piece is lost, the amount of cooling water decreases, thereby decreasing the cooling ability of the electrode surface and increasing the amount of oxidation of the electrode.

In addition, moisture is penetrated into the centerpiece made of refractory, and the service life is reduced, and since the current and the slag are fixed around the centerpiece, electric sparks are generated and holes are formed in the water-cooling panel or the water-cooled ceiling. .

The present invention has been made in order to solve the above problems, it is to prevent the clogging of the nozzle of the cooling water ring installed around the electrode to improve the cooling efficiency is to prevent the electrode from being oxidized by the atmosphere. It is also another object to prevent the productivity drop by preventing the electric spark generated by the current attached to the center piece.

1 is a configuration diagram schematically showing a general electric furnace.

2 is a perspective view showing the electrode consumption consumption reducing apparatus according to the present invention.

3 is a view showing the installation state of the cooling water ring and the injection ring of the electrode consumption reduction device according to the present invention.

Figure 4 is a graph showing the amount of cooling water remaining according to the nitrogen injection angle in the electrode consumption reduction device according to the present invention.

5 is a graph showing the oxidation rate according to the temperature of the electrode.

<Description of the symbols for the main parts of the drawings>

10: nozzle 12: cooling water ring

14: spray ring 16: spray ring nozzle

56 electrode

Therefore, in order to achieve the above object, in the electrode consumption reduction device for reducing the consumption of the electrode rod by spraying the cooling water to the electrode through the nozzle of the cooling water ring, the nitrogen in the center of the electrode rod in the lower portion of the cooling water ring Provided is an electrode consumption reduction device including an injection ring formed with a nozzle to be injected.

Here, the injection ring is preferably formed in the nozzle 45 ° to 75 ° downwards.

Hereinafter, the electrode consumption consumption reduction apparatus according to the present invention will be described with reference to the accompanying drawings.

1 is a configuration diagram schematically showing a general electric furnace, Figure 2 is a perspective view showing the electrode consumption consumption reducing apparatus according to the present invention, Figure 3 is a state of installation of the cooling water ring and the injection ring of the electrode consumption consumption reducing apparatus according to the present invention 4 is a graph showing the amount of cooling water remaining according to the nitrogen injection angle in the electrode consumption consumption reduction apparatus according to the present invention.

According to the above drawings, the electric arc furnace (Electric Arc Furnace) is a refractory body consisting of a refractory and a water cooling panel (50), a roof (Roof) 52 installed on the top of the furnace body 50, and the refractory in the center of the roof 52 It consists of a center piece 54 made of, and one to three electrode bars 56 are formed so that the center piece 54 can be raised and lowered. Here, an arc is generated between the electrode rod 56 and the scrap metal inside the furnace body 50, and the scrap metal is melted due to the arc heat generated at this time.

On the other hand, a slag door 58 is formed at the center of the front side of the electric furnace, so that oxygen and carbon are injected through the slag door 58 so that cutting work and slag foaming of scrap metal can be performed. have.

In this way, the inside of the electric furnace is encouraged by the oxygen blown by the oxidizing component, this oxidizing atmosphere chemically consumes the electrode (56).

Electrode consumption reduction device according to the present invention is injected to the cooling water through the nozzle 10, the cooling water ring 12 for cooling the electrode 56, and is installed in the lower portion of the cooling water ring 12 to inject nitrogen to cool the water ring ( 12 is made of a spray ring 14 for preventing the clogging of the nozzle 10.

First, the cooling water ring 12 for spraying the cooling water is installed at 100 mm to 150 mm away from the outer circumferential surface of the electrode 56 so that the sparking does not occur with the electrode rod 56 and the cooling water can be smoothly injected.

In addition, the cooling water ring 12 is different depending on the diameter of the electrode 56, but 30 to 50 nozzles 10 are formed. In addition, the coolant is preferably installed to be inclined downward 40 ° to 50 ° from the horizontal line so as not to splash after reaching the electrode (56).

Next, the injection ring 14 is installed to the outside of the cooling water ring 12 in the lower portion of the cooling water ring 12. The spray ring 14 is formed such that the nozzle 16 is inclined downward toward the center of the electrode 56 so that nitrogen is injected into the electrode 56. Here, the forming direction of the nozzle 16 is preferably formed to be inclined downward 45 ° to 75 ° downward.

Example 1

In this embodiment, the residual amount of cooling water according to the injection angle of nitrogen was measured to select an appropriate blowing angle of nitrogen.

First, the spray angle of the coolant was horizontally 45 ° downward with respect to the electrode bar, and the amount of coolant was measured with the blowing angle of nitrogen being 0 ° to 80 °.

Here, the injection conditions of the cooling water and the blowing conditions of nitrogen are shown in Table 1 below.

Item Contents Coolant flow rate 1 L / min Nitrogen Blowing Pressure 2 kg / cm2 Nitrogen injection angle 0 to 80 ° Round bar diameter / length 28 inch / 1,000mm

As shown in FIG. 6, the amount of the coolant remaining in the lower portion of the electrode rod 56 according to the nitrogen blowing angle during the spraying of the coolant is shown in FIG. 6.

As shown in FIG. 6, as the injection angle of nitrogen increases, interference of blown nitrogen with respect to the cooling water decreases, and thus the amount of remaining coolant increases.

In addition, when the spraying angle of the coolant is 45 ° or less, the coolant and nitrogen are not properly delivered to the surface of the electrode rod 56 due to mutual interference, and thus the amount of coolant remaining rapidly decreases.

That is, in order to increase the amount of cooling water flowing to the surface of the electrode rod 56, the injection angle of nitrogen must be larger than the cooling water injection angle.

In addition, in order to minimize the effect of dust coming from the top of the furnace as shown in Figure 6 the blowing angle of nitrogen is appropriate 75 °.

On the other hand, when the blowing angle is 90 °, dust generated from the lower portion is infiltrated into the cooling water ring 12, the nozzle 10, and closes the nozzle 10.

Therefore, the blowing angle of nitrogen should be 45 ° or more so as not to interfere with the cooling water, and should be below 75 °, which is the proper blowing angle.

As such, the nozzle 16 of the injection ring 14 is preferably 45 ° to 75 ° such that the blowing angle of nitrogen is 45 ° to 75 °.

Example 2

Next, the injection ring 14 is installed so that the gas can be injected at a position of about 50 mm to 100 mm to the outside of the cooling water ring 12 for injecting the cooling water.

In order to minimize oxidation of the electrode, the injection gas used nitrogen (N 2), which is an inert gas.

The flow rate of the cooling water injected through the nozzle 10 of the cooling water ring 12 was set to 7-8 L / min, and the pressure of nitrogen injected through the nozzle 16 of the injection ring 14 was 5-6 kg / cm 2. Set.

At this time, the blowing angle of nitrogen was set to 60 °, which is larger than the blowing angle of the cooling water, to exclude the interference of the cooling water.

Table 2 compares when nitrogen is not blown through the injection ring (Comparative Example 1) and when nitrogen is taken through the injection ring (Comparative Example 2).

Item Comparative Example 1 Comparative Example 2 Electrode Cooling Method cooling water Coolant + nitrogen Gas (Nitrogen) Blowing Angle - 60 ° Coolant nozzle clogging rate (%) 60% 5% Electrode surface temperature (℃) 700 ~ 1,000 ℃ 600 ~ 800 ℃

As shown in Table 2 above, when the nitrogen is blown, the blockage of the cooling water ring 12 nozzle 10 for spraying the cooling water is remarkably reduced, so that the cooling water is uniformly injected to the electrode rod 56, and thus the electrode rod 56. It can be seen that the temperature of is reduced.

Example 3

When operating 40% of molten iron in an actual electric furnace, the results of the cooling of the electrode with nitrogen (Comparative Example 3) and the cooling of the electrode with conventional cooling water only (Comparative Example 4) are shown in Table 3 below. Same as

Item Comparative Example 3 Comparative Example 4 Electrode Consumption (kg / ts) 1.10 kg / ts 0.95 kg / ts Electrode exchange cycle (Ch / piece) 12.5 13.2 Center Piece Life (time / Ch) 100-110 170-200

As can be seen in Table 3 above, when cooling the electrode 56 using nitrogen, the consumption of the electrode 56 is reduced, and the cooling capacity and flow of the cooling water flowing on the surface of the electrode 56 are uniform, resulting in a center piece. Since the cooling water dropped to 54 is reduced, the service life of the center piece 54 is also improved.

As described above, according to the present invention, since the injection ring is provided outside the cooling water ring to blow in nitrogen, it is possible to prevent clogging of the cooling water ring nozzle.

Therefore, the cooling efficiency of the cooling water flowing through the electrode is increased to reduce the consumption of the electrode that is oxidized.

In addition, since the life of the electrode is improved, the maintenance time for replacing it is shortened, thereby increasing the productivity of the electric furnace.

Claims (2)

In the electrode consumption reduction device for reducing the consumption of the electrode rod by spraying the cooling water to the electrode rod through the nozzle of the cooling water ring, Electrode consumption reduction device characterized in that it comprises a spray ring formed with a nozzle so that nitrogen is injected in the lower direction of the electrode rod in the lower portion of the cooling water ring. The method of claim 1, The injection ring electrode consumption reduction device, characterized in that the nozzle is formed at 45 ° to 75 ° downward.