KR20020037973A - Immersion vessel of vacuum degassing system - Google Patents

Abstract

PURPOSE: A deposition pipe of vacuum degassing system is provided, to improve the refluxing amount by installing proper number of gas spray nozzle for refluxing the melt steel in proper angle. CONSTITUTION: The deposition pipe is such that it is installed in the lower part of the vacuum bath(10) of the vacuum degassing system(1) and has a gas spray nozzle(40) for ascending melt steel(30) ascended at a raddle(20) to the vacuum bath(10) and refluxing the melt steel(30). The gas spray nozzle(40) for refluxing the melt steel(30) is installed with inclination and diagonally in the center line of the deposition pipe internal brick(60) to promote the refluxing the melt steel(30) ascended into the deposition pipe(50). The gas spray nozzle(40) is installed to be sloped by equal angle to an X-axis and a Y-axis by the axis of the center line of internal brick(60).

Description

Immersion pipe of vacuum degassing facility which raised reflux {IMMERSION VESSEL OF VACUUM DEGASSING SYSTEM}

The present invention relates to a vacuum degassing system (VACUUM DEGASING SYSTEM), which is one of the off-shore refining facilities, and more particularly, a deposition pipe (rising pipe) installed above the ladle to reflux molten steel in the ladle in the vacuum degassing facility. By installing the gas injection nozzle for reflux of molten steel at the proper number and angle, the reflux of molten steel can be performed more smoothly, which reduces the operating time of the equipment due to the increased reflux and extends the life of the sedimentation pipe. It is about the deposition pipe of the vacuum degassing plant which raised the reflux amount to make it possible.

In general, the melted water in the electric furnace is not impurity, and most of the components of the special steel desired are less than the state. Therefore, it is received in a separate container (LADLE) and decarburized for removing impurities such as carbon component (C). This operation is referred to as an external refining operation, and the type of the external refining operation is mainly vacuum degassing (VD), vacuum decarburization (VOD) and vacuum degassing such as argon and oxygen decarburization (AOD) and oxygen or argon The gas is divided into several ways to remove impurities from the steel.

A typical vacuum degassing apparatus of such an off-road refining method is shown in FIG. 1.

That is, as shown in Figure 1, the two rising pipe and the down pipe 120, 130 is deposited on the upper portion of the ladle 110, the molten steel 100 is contained therein, and the upper and lower vacuum chamber thereon (140, 150) is located, the reflux operation of the molten steel 100 after the rising pipe 120 is deposited in the molten steel 100 of the ladle 110, the rising pipe 120, which is the deposition pipe of the lower portion of the vacuum tank 130, When the argon (Ar) or nitrogen (N2) gas is blown through the reflux gas injection nozzle 200 installed at the 120 and connected to the external reflux gas line 210, the bubbles 220 are injected into the molten steel 100. By gradually increasing the molten steel to the riser 120, if the vacuum exhaust in the vacuum pump equipment is started in full-fledged reflux operation.

That is, the reflux molten steel 100, which is gradually raised due to the intake of the vacuum exhaust and the reflux gas, is raised to a certain height of the lower vacuum tank 150, and the elevated molten steel 100 is lowered to the downcomer 130 due to its own static pressure. If it is lowered, and thus, the continuous reflux operation of the molten steel 100 as described above, the refining operation such as decarburization work is made.

At this time, as shown in Figure 2, looking at the injection nozzle 200 for the reflux gas installed in the conventional deposition pipe (rising pipe) in more detail, the conventional injection nozzle 200 is the outside of the deposition pipe 120 About six at a predetermined angle so as to face the center of the molten steel 100 in the riser 120 through the casing 230 and the inner shell 240 and the molten steel 100 in contact with the molten steel 100. Is installed, such injection nozzle 200 is connected to approximately six reflux gas line 210 is connected to the external fastening unit 212.

At this time, W and F which are not described are the cooling water passages and the flanges mounted on the outer periphery thereof.

Therefore, as illustrated in FIGS. 9A and 10A, argon or nitrogen gas injected by the conventional reflux gas injection nozzle 200 is sprayed only at the center of the riser 120 in a horizontal state. Blowing phenomenon in which the gas collides with each other generates a reflux reaction stagnant zone where reflux is not formed at the lower portion of the molten steel 100, which causes a problem of lowering the reflux amount of the molten steel.

As a result, the reflux of the molten steel is delayed or the reflux height of the molten steel passing through the lower vacuum tank 140 and the downcomer tube 130 in the rising pipe 120 is lowered, so that the amount of carbon (C) removed from the molten steel 100 is reduced.

This is because the higher the refluxing height, that is, the higher the rising height of the molten steel, the more carbon components of the molten steel are removed. If such decarburization is not performed smoothly, the cleanliness of the molten steel is lowered, thereby degrading the quality of the product. Due to the blowing phenomenon, the internal edges of the immersion pipe 120 are worn out rapidly, resulting in equipment defects at the same time, while decarburization and degassing work are delayed, thereby providing a cause of cost increase due to equipment operation. there was.

The present invention has been made in order to improve the various problems as described above, the object is that the reflux operation of molten steel in the vacuum degassing equipment proceeds extremely smoothly, decarburization and degassing work time is shortened according to the operation of the equipment While the cost is reduced, smooth reflux of molten steel proceeds, the decarburization amount is increased, and the cleanliness of molten steel is improved, thereby providing a deposition tube of a vacuum degassing facility having a high reflux amount which improves quality.

In addition, another object of the present invention is to reduce the blowing phenomenon during the gas injection to reflux the molten steel, thereby reducing the internal smoke and wear of the immersion pipe due to the gas collision, and thus the life of the equipment as well as the lag of the immersion pipe It is to provide a deposition tube of a vacuum degassing plant with an increased reflux amount to be extended.

1 is a schematic diagram showing the molten steel reflux operation of the general molten steel degassing equipment

(A) and (b) of FIG. 2 are schematic front and plan views showing a deposition tube and a reflux gas injection nozzle of a conventional vacuum degassing facility;

Figure 3 is an overall configuration showing the installation state of the immersion pipe of the vacuum degassing facility to increase the reflux amount of the present inventors

Figure 4 (a) and (b) is a schematic front and plan view showing the deposition pipe and the reflux gas injection nozzle of the vacuum degassing equipment to increase the reflux amount of the present invention

Figure 5 (a) and (b) is a schematic diagram showing the main part and the reflux state of the molten steel showing the gas injection nozzle in the deposition pipe of the vacuum degassing facility of the present invention with a high reflux amount

6 to 8 (a) and (b) is a main part side, a plan view and a side view showing the installation location and angle of the fuel gas injection nozzle of the deposition pipe according to the prior art and the present invention

9 to 10 (a) and (b) are plan views showing the molten steel reflux state in the immersion pipe according to the prior art and the present invention

Explanation of symbols on the main parts of the drawings

Degassing Equipment

20 ... ladle 30 ... molten steel

40 .... spray nozzle 50 ....

60 .... Inner smoke and C .... Inner smoke and centerline

X, Y axis ... longitudinal and transverse axis with inner edge

As a technical configuration for achieving the above object, the present invention is installed in the lower part of the vacuum chamber of the degassing equipment and raised in the ladle in the immersion pipe having a gas injection nozzle for raising the molten steel to the vacuum chamber and reflux of the molten steel In the molten steel reflux gas injection nozzle, the deposition pipe of the vacuum degassing equipment to increase the reflux is installed to be inclined diagonally from the centerline (C) of the inner side of the immersion tube to facilitate the reflux of the molten steel rising into the immersion tube. By providing.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 3 is an overall configuration showing the installation state of the immersion pipe of the vacuum degassing equipment to increase the reflux amount of the present invention, Figure 4 (a) and (b) is the deposition of the vacuum degassing equipment to increase the reflux amount of the present invention A schematic front and plan view showing a pipe and a reflux gas injection nozzle, and FIGS. 5A and 5B illustrate main parts of a gas injection nozzle in a deposition tube of a vacuum degassing facility having a high reflux amount according to the present invention, and It is a schematic diagram showing the reflux state of the molten steel according to.

Figure 3 shows a degassing plant 1 according to the present invention, the degassing plant 1 is a deposition pipe 50, that is, molten steel in the lower portion of the upper and lower vacuum chamber (10a) (10) A submerged tube 50 made of a descending tube 50a descending to the ladle 20 is installed through the rising tube 50 and the vacuum chamber 10, and the molten steel 30 is lowered to the submerged tube 50. ) Is placed ladle 20, the deposition pipe 50, that is, the riser 50, the inert gas, that is, argon (Ar) or nitrogen (N2) gas in the riser 50 for the reflux of the molten steel A reflux gas injection nozzle 40 blown into the molten steel is provided.

On the other hand, Figure 4 and Figure 5a shows the injection nozzle 40 in more detail, such a reflux gas injection nozzle 40, smoothly refluxing the molten steel 30 that is raised into the settling pipe (50). It is installed to be inclined diagonally from the center line (C) of the inner tube 60 and the dip pipe.

In addition, the gas injection nozzle 40 is inclined at the same angle with respect to the center line C of the inner edge 60 and the X axis and the Y axis, respectively, such a gas injection nozzle 40, As shown in FIGS. 6B to 8B, the center lines C of the inner edge 60 are inclined at 45 degrees on the X and Y axes, respectively.

In addition, such a gas injection nozzle 40, the inner edge 60 is separated from each other from the first stage inner edge (60c) of the bottom to the third stage inner edge (60a) of the upper in the same area separated by 90 degrees intervals. They are mounted diagonally in different rows.

And, as shown in Figure 4, the gas injection nozzle 40, each of the reflux gas pipe 42 along the inner edge 60 of the immersion pipe 50 is the inner edge of the immersion pipe 40 (60) , Consisting of a total of 12 are installed to pass through the iron shell 70 and the castable 80.

Referring to the operation and effects of the present invention made in the above configuration in more detail as follows.

3 to 10, when the molten steel 30 in the ladle 20 is refluxed in the vacuum degassing facility, which is an external refining facility, the molten steel 30 through the rising pipe 50 is more smoothly refluxed and removed. While the decarburization time of the gas equipment is shortened, the molten steel reflux height in the vacuum chamber 10 is increased to increase the decarburization amount, thereby improving product quality and depositing pipe 50 due to the blowing phenomenon of the injected reflux gas (G). The internal lead and the deposition pipe 50 of the vacuum degassing facility with the increased reflux amount of the present invention to effectively prevent the shortening of the life is as follows.

The molten steel 30 filled in the ladle 20 of the degassing facility 1 rises by the exhaust operation of the vacuum pump units of the vacuum tanks 10a and 10 to the rising pipe 50 above the ladle 20. When the injection nozzle 40 installed in the riser pipe 50 injects argon or nitrogen gas which is an inert gas to reflux molten steel in the riser 50, the carbon generated by the gas bubbles generated at this time is It is mixed with oxygen (O) and discharged outside as carbon monoxide (CO), and eventually carbon in molten steel is removed. Such carbon removal is called decarburization.

At this time, the important thing is that as the reflux of the molten steel proceeds smoothly, the reflux time of the molten steel increases to shorten the decarburization time, and the decarburization amount also increases, so that the reflux of the molten steel is smoother. X-axis of the reflux gas injection nozzle 40 installed in the ascending pipe 50 in a diagonal direction from the center line C of the inner tube 60 of the deposition tube, that is, the center line C of the inner edge 60 The same angle with respect to the Y axis and the Y axis is preferably installed at an inclination of 45 degrees.

At the same time, the gas injection nozzle 40 of the present invention, when the inner edge 60 is separated by 90 degrees, the first stage inner edge 60c of the bottom in the same area (A) and the third stage inner edge of the upper portion Up to 60a are mounted in different rows in diagonal directions, respectively.

That is, as shown in FIG. 6, the installation state of the gas injection nozzle 40 and the conventional injection nozzle 200 according to the present invention will be described in detail. In the related art, the injection nozzle 200 is applied to the internal edge 250 of the second stage. Compared to the 140 mm spaced in the center (Fig. 6a), in the present invention, the reflux gas is injected to each of the three stages of the inner edge (60a)-(60c) and installed in different rows (Fig. 5a) Is uniformly sprayed on the entire molten steel.

Next, as shown in FIG. 7 and FIG. 8, in the related art, gas is sprayed in the molten steel in a horizontal state along the centerline C of the soft wire 250, but in the present invention, The center line C is inclined at about 45 degrees with respect to the X and Y axes, respectively (FIGS. 7B and 8B), and as shown in FIG. 4, the inner lines 60 of the immersion pipe 50 are respectively A total of twelve reflux gas pipes 42 are connected to pass through the inner edge 60 of the immersion pipe 40, the steel bar 70, and the castable 80.

Therefore, as illustrated in FIGS. 9A and 10A, conventionally, the injected gas G has to collide at the center of the riser 120, so that a blowing phenomenon occurs due to a gas collision, and in particular, the molten steel below Part of the reflux stagnation portion is not generated, but as shown in Figure 9b and 10b, in the present invention, the gas injected from the nozzle 40 in a uniformly arranged state in the inclined state smoothly generates reflux As such, the molten steel 30 rises extremely smoothly through the rising pipe 50, which increases the reflux height of the molten steel 30 and decreases the decarburization time and increases the decarburization amount.

That is, in the present invention, the gas injection nozzle 40 is uniformly arranged in the diagonal direction between the inner edges of the first stage and the third stage and 60a-60c so that the molten steel 30 is below the riser 50. This is because the reflux gradually increases strongly from the part to the upper part, thereby increasing the reflux height.

In addition, as the injection gas is injected in the inclined direction, damage of the inner lead and 60 due to the gas collision is prevented, and eventually, the life of the inner pipe 60 of the immersion pipe 50 is increased to enable cost reduction.

Table 1 below shows the reflux amount according to the prior art and the present invention as a comparison table.

division Reflux (ton) Conventional (single stage) The present invention (three steps) 80N㎥ / min 150N㎥ / min 200N㎥ / min 100N㎥ / min 250N㎥ / min 300N㎥ / min 400 torr 71.1 96.6 105.4 81.4 102.6 110.5 200 torr 90.8 123.3 134.5 104 131 141.1 1 torr 155 210.3 229.5 177.4 223.5 240.8

(Reflux Q = 114 * G ^1/3 * D ^3/4 * [Ln * (P ₀ / P)] ^1/3 , where G is the amount of reflux gas (Nm ³ / min) and D is Immersion pipe diameter (0.73m), P ₀ is atmospheric pressure (torr), P is vacuum pressure (torr))

As can be seen in Table 1, the nozzle 40 of the present invention generates more reflux amount than the conventional nozzle 200, which in turn increases the reflux height of the molten steel to increase the decarburization efficiency.

Table 2 below shows the conventional and the present invention as a comparison table with respect to the life of the inner edge 60.

Yeonwa Contents Conventional The present invention part A B C D A B C D 3-stage Remaining (mm) 175 180 180 170 180 175 175 180 Survival rate (%) 0.15 0.23 0.19 0.19 0.20 0.19 0.19 0.20 Life Span 521 480 536 536 525 516 516 527 2-stage Remaining (mm) 120 150 145 139 140 135 142 140 Survival rate (%) 0.25 0.29 0.27 0.29 0.25 0.23 0.23 0.25 Life Span 415 425 420 426 409 420 425 415 1 stage Remaining (mm) 90 110 100 110 100 95 95 105 Survival rate (%) 0.34 0.32 0.34 0.31 0.39 0.31 0.31 0.27 Life Span 330 339 320 360 320 392 360 412

That is, as can be seen in Table 2, when the immersion pipe 50 is divided into four parts (AD) at intervals of 90 degrees, based on the number of uses of the injection nozzle 40, in the case of the present invention more than conventional It can be seen that the lifetime remains long, which in the present invention improves the inner edge and life of the immersion pipe 50.

Next, Table 3 shows the decarburization time by comparing the present invention with the prior art.

In case of ultra low coal processing Decarburization Rate (Ct) (%) Processing time (minutes) Decarburization Rate Constant (Kc) (min ^-1 ) Conventional 11.8 28.20 0.13 The present invention 15.2 22.12 0.15 Related Expressions C + O = steel decarburization scheme for CO (g) Ct = Co * exp (-Kc * t) Co; C concentration in initial molten steel Kc = Q / V * a _k / (Q + a _k ) Q; Molten steel reflux (Ton / min) V; Molten steel amount in ladle a _k ;

That is, as can be seen in Table 3, in the case of the present invention, the tantalum rate is improved and the decarburization time is shortened as compared with the conventional case, and the decarburization rate constant is further improved.

Therefore, as can be seen from Table 1-3, when the nozzle 40 of the present invention is used, the reflux amount of the vacuum degassing equipment is increased, the quality is improved by increasing the decarburization amount, in particular the inside of the immersion pipe 50 The lead 60 is extended to achieve cost savings.

Thus, according to the immersion tube of the vacuum degassing facility of the present inventors having increased the reflux amount, the reflux operation of molten steel in the vacuum degassing facility proceeds extremely smoothly, thereby reducing the cost of decarburization and degassing operation and reducing the cost of equipment operation. On the other hand, the smooth reflux of the molten steel is advanced to increase the decarburization amount has the advantage of improving the quality of the molten steel is improved.

In addition, since the blowing phenomenon is reduced during the gas injection to reflux the molten steel, the internal smoke and wear of the immersion pipe due to the gas collision is reduced, and accordingly, there is an excellent effect of further extending the life of the equipment as well as the lag of the immersion pipe. will be.

While the invention has been shown and described with respect to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit or scope of the invention as set forth in the claims below. I would like to know that those who have knowledge of this can easily know.

Claims (5)

The molten steel 30 which is installed under the vacuum chamber 10 of the degassing facility 1 and is raised in the ladle 20 is raised to the vacuum chamber 10 and a gas injection nozzle 40 for reflux of the molten steel 30 is performed. In the immersion pipe 50 having the The molten steel reflux gas injection nozzle 40 is installed to be inclined diagonally from the centerline (C) of the inner tube 60 of the immersion pipe so as to smoothly reflux the molten steel 30 that rises into the settling pipe 50. Sedimentation pipe of vacuum degassing facility which increased reflux According to claim 1, wherein the gas injection nozzle 40 to increase the reflux amount, characterized in that the inclined at the same angle around the X axis and the Y axis with respect to the center line (C) of the inner edge 60, respectively Sedimentation pipe of vacuum degassing facility 3. The vacuum degassing of claim 2, wherein the gas injection nozzle 40 is installed at an angle of 45 degrees to an X axis and a Y axis about the center line C of the inner edge 60, respectively. Sedimentation pipe of gas equipment 3. The gas jet nozzle (40) according to claim 2, wherein the gas injection nozzle (40) is formed at the upper end of the third stage inner edge (60c) at the first stage inner edge (60c) of the bottom in the same region separated from the inner edge (60) by 90 degrees ( Submerged pipe of a vacuum degassing facility with increased reflux, characterized in that it is installed diagonally in different rows up to 60a) According to claim 4, The gas injection nozzle (40) along the inner edge of the immersion pipe 50, each of the reflux gas pipe 42 is the inner edge of the immersion pipe 40, 60, the shell 70 ) And a total of 12 pipes connected through the castable 80 are installed to increase the reflux amount of the vacuum degassing equipment