KR20070103345A - Filler for ladle receiving molten steel - Google Patents

Abstract

A filler for steel ladle is provided to expand the volume of dicalcium silicate contained within the filler and rupture when the filler is cooled, thereby freeing the clogged injection port blocked by the sintered filler due to long hours of contact with the molten steel, consequently allowing high yield of molten steel being tapped. In a filler(300) filled at the injection port disposed at a lower part of a steel ladle, the filler contains 60 to 72% of CaO and 28 to 40% of SiO2 by weight respectively. The filler, while in use inside the injection port, forms dicalcium silicate. When the filler is cooled, the dicalcium silicate goes through a phase transformation and expands in volume, causing the filler to erupt and unclog the blocked injection port. The filler can contain 66% of CaO and 34% of SiO2 by weight respectively. The filler containing 42 to 68% of CaO, 4 to 36% of SiO2, and 10 to 40%of Al2O3 by weight respectively is injected inside the injection port, and while in use, forms the dicalcium silicate. The dicalcium silicate goes through a phase transformation when the filler is cooled, and expands in volume, causing the filler to burst and expose the injection port. The cooling of the filler is brought on by a non-active gas(85).

Description

Filler for steel ladle {FILLER FOR LADLE RECEIVING MOLTEN STEEL}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to fillers for receiving ladles, and more particularly to fillers for receiving ladles that can be easily discharged by being differentiated by volume expansion during phase transformation.

Referring to FIG. 1, which is a schematic cross-sectional view of a steel ladle carrying molten steel, the steel ladle 10 may blow inert gas to equalize the temperature or components in the wall 20 and molten steel 30 that are made of refractory materials. The outlet 40 is formed on the bottom of the wall 20 to cast the plug 40 and the molten steel 30 is completed and the sliding port for opening and closing the molten steel 30 and the outlet 50 The gate 60.

Referring to FIG. 2, which is an enlarged view of the outlet, the outlet 50 is formed by a well block 70 and a top nozzle 80. A fixing plate 90 and a fixing plate 90 which are fixed to the well block 70 and the top nozzle 80 under the discharge port 50 and have a first opening 91 through which molten steel can be discharged. The sliding nozzle plate 100 is formed to be movable in the lower portion and has a second opening 101, and is fixed to the lower portion of the sliding nozzle plate 100 to surround the second opening of the sliding nozzle plate 100. A shroud nozzle 110 having a third opening 111 is provided.

If the molten steel 30 in the receiving ladle having such a configuration blocks the sliding nozzle plate 100 while the molten steel 30 in the receiving ladle enters the top nozzle 80 and the well block 70, the molten steel 30 is the top nozzle. Due to the thermal contact with the 80 and the well block 70, the temperature is lowered to solidify and the molten steel 30 cannot be discharged. Therefore, the filler 200 is filled in the top nozzle 80 and the well block 70 before the molten steel is contained in the ladle to prevent intrusion into the discharge port 50 (see FIG. 1) and at the same time prevent solidification of the molten steel.

Such fillers include fillers comprising 70-90% of chromite sand and 10-30% of silica sand, having a size of 500-1000 μm, disclosed in US Pat. No. 6,051,514, and There is a filler of US Pat. No. 6,316,106 which further comprises 0.05-5% of carbon black in the filler disclosed in US Pat. No. 6,051,514.

However, even in the U.S. patent, when producing steel grades having a long processing time in ladles or using a large amount of alloy, sintering occurs in these fillers due to the contact between the hot molten steel and the fillers, and when integrated, Even if the sliding nozzle plate of the opening is not discharged, there is a problem that can not perform the continuous casting process.

In this case, the lower side of the filler is usually discharged because the sintering is not progressed, and the sintered layer remains only on the upper side. When the sintered layer is thin, oxygen may be blown out, but this may also be impossible if the sintered layer is formed thick. Therefore, the molten steel must be reloaded into the converter to remove the sintered layer and then the molten steel must be treated again. In addition, the process of removing the sintered layer by blowing oxygen has a problem that the molten steel is exposed to the air and deteriorates the quality of the cast steel because the operation is dangerous and the shroud nozzle for blocking the air cannot be used.

Accordingly, an object of the present invention is to provide a filler for a steel ladle that can be easily discharged even when the filler is in contact with molten steel for a long time and sintering occurs.

Filling ladle filler in the lower inlet in the receiving ladle according to the present invention comprises a dicalcium silicate (dicalcium silicate), the filler sintered in the inlet is differentiated by volume expansion by phase transformation during cooling Open the inlet.

In this case, the filler contains 60-72% CaO and 28-40% SiO ₂ , preferably 66% CaO and 34% SiO ₂ by weight. The filler may also contain 42-68% CaO, 4-36% SiO ₂ and 10-40% Al ₂ O ₃ . At this time, the cooling of the filler may be by air cooling, but is preferably performed by an inert gas.

By providing the filler for the steel ladle according to the present invention, the filler can be easily discharged even when sintering occurs in contact with the molten steel for a long time, thereby improving the error rate of the molten steel without deteriorating the quality of the cast steel.

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

Figure 3 is an enlarged view of the discharge port in which the filler for the receiving ladle according to the present invention.

Referring to FIG. 3, the outlet 50 (see FIG. 1) is formed by the well block 70 and the top nozzle 80. A fixing plate 90 having a first opening 91 fixed to the well block 70 and the top nozzle 80 and having a molten steel 30 through which the lower portion of the discharge port 50 can be discharged; (90) a sliding nozzle plate (100) formed to be movable in a lower portion and having a second opening (101), and a lower portion of the sliding nozzle plate (100) to surround a second opening of the sliding nozzle plate (100). A shroud nozzle 110 is provided which is fixed and has a third opening 111.

If the molten steel 30 in the receiving ladle having such a configuration blocks the sliding nozzle plate 100 while the molten steel 30 in the receiving ladle enters the top nozzle 80 and the well block 70, the molten steel 30 is the top nozzle. Due to the thermal contact with the 80 and the well block 70, the temperature is lowered to solidify and the molten steel 30 cannot be discharged. Therefore, the filler for the steel ladle according to the present invention inside the top nozzle 80 and the well block 70 before the molten steel is contained in the ladle to prevent intrusion of the molten steel into the discharge port 50 and prevent solidification of the molten steel. 300).

Filler 300 for the steel ladle according to the present invention includes dicalcium silicate (dicalcium silicate). The dicalcium silicate contains by weight 60-72% CaO and 28-40% SiO ₂ , preferably 66% CaO and 34% SiO ₂ . In addition, the steel ladle filler 300 according to the present invention is not limited to a two-component system, the present invention can be applied to a ternary or more filler having a composition in which dicalcium silicate is produced. For example, the filler for the steel ladle according to the present invention may further include 40% or less of Al ₂ O ₃ in addition to CaO and SiO ₂ .

The dicalcium silicate is stable at a high temperature of more than 1200 degrees Celsius α or α 'phase and transformed into a phase γ at 725 degrees Celsius, with about 16% volume expansion resulting in dicalcium silicate self-differentiation in the outlet. Therefore, since the filler 300, which is the dicalcium silicate in the lower portion of the outlet, is not sintered because of low temperature, when the sliding nozzle plate 100 is opened, the lower filler is discharged and sintered in contact with the molten steel 30. The upper filler is cooled from the lower. At this time, the dicalcium silicate present in the α or α 'phase undergoes about 16% volume expansion while transforming into the γ phase and is differentiated and discharged in the outlet.

In this case, an inert gas supply unit (not shown) formed inside the top nozzle 80 to cool the phase transformation of the dicalcium silicate to the phase transformation temperature or less within a short time may promote phase transformation more effectively.

Experimental Example 1

Experimental Example 1 was mixed into a total amount of 30g using a reagent CaO and SiO ₂ to investigate the differentiation of the filler for steel ladle according to the present invention using a phase transformation into a graphite crucible having a diameter of 30mm The ratio of the sample which passed through it by using a 1 mm sieve was hold | maintained for 3 hours in the electric furnace of 1500 degreeC, blowing in an inert gas for protecting a graphite crucible, and cooling to room temperature. Table 1 shows the chemical components of the samples and the experimental results. As can be seen from Table 1, it can be seen that part or all of the sample is differentiated only in the range in which the component range of the sample produces dicalcium silicate (CaO: 59-72%).

Sample Number One 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Compounding composition (%) CaO 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 SiO ₂ 50 48 46 44 42 40 38 36 34 32 30 28 26 24 22 -1mm ratio (%) 0 0 0 0 0 23 51 92 100 97 48 9 0 0 0

Experimental Example 2

This Experimental Example 2 is a reagent CaO, SiO ₂ to investigate the differentiation phenomenon of the filler for steel ladle according to the present invention using the phase transformation And after mixing so that the total amount is 30g using 10% Al ₂ O _{3 It} is placed in a graphite crucible having a diameter of 30mm and maintained for 3 hours in an electric furnace of 1500 degrees Celsius while blowing an inert gas to protect the graphite crucible. After cooling to room temperature, the ratio of the sample which passed through it using the 1 mm sieve was adjusted. Table 2 shows the chemical components of the samples and the experimental results. As can be seen from Table 2, it can be seen that a part of the sample is differentiated only in the range in which the component range of the sample produces dicalcium silicate (CaO: 54-68%).

Sample Number 16 17 18 19 20 21 22 23 24 25 26 27 Formulation Composition (%) CaO 50 52 54 56 58 60 62 64 66 68 70 72 SiO ₂ 40 38 36 34 32 30 28 26 24 22 20 18 Al ₂ O ₃ 10 10 10 10 10 10 10 10 10 10 10 10 -1mm ratio (%) 0 0 2 42 62 78 80 74 56 28 0 0

Experimental Example  3

Experimental Example 3 is the same as Experimental Example 2, except that the content of Al ₂ O ₃ is 20%. The results of this experimental example are shown in Table 3. As can be seen from Table 3, it can be seen that a part of the sample is differentiated only in the range where the component range of the sample produces dicalcium silicate (CaO: 52-66%).

Sample Number 28 29 30 31 32 33 34 35 36 37 38 39 Formulation Composition (%) CaO 48 50 52 54 56 58 60 62 64 66 68 70 SiO ₂ 32 30 28 26 24 22 20 18 16 14 12 10 Al ₂ O ₃ 20 20 20 20 20 20 20 20 20 20 20 20 -1mm ratio (%) 0 0 51 64 69 64 58 52 46 22 0 0

Experimental Example  4

Experimental Example 4 is the same as Experimental Example 2, except that the content of Al ₂ O ₃ is 30%. The results of this experimental example are shown in Table 4. As can be seen from Table 4 below, it can be seen that a part of the sample is differentiated only in the range in which the component range of the sample produces dicalcium silicate (CaO: 46-62%).

Sample Number 40 41 42 43 44 45 46 47 48 49 50 51 Formulation Composition (%) CaO 44 46 48 50 52 54 56 58 60 62 64 66 SiO ₂ 26 24 22 20 18 16 14 12 10 8 6 4 Al ₂ O ₃ 30 30 30 30 30 30 30 30 30 30 30 30 -1mm ratio (%) 0 18 32 46 51 48 44 48 30 14 0 0

Experimental Example  5

Experimental Example 5 is the same as Experimental Example 2, except that the content of Al ₂ O ₃ is 40%. The results of this experimental example are shown in Table 5. As can be seen from Table 5, it can be seen that a part of the sample is differentiated only in the range in which the component range of the sample produces dicalcium silicate (CaO: 42-58%).

Sample Number 52 53 54 55 56 57 58 59 60 61 62 Formulation Composition (%) CaO 38 40 42 44 46 48 50 52 54 56 58 SiO ₂ 22 20 18 16 14 12 10 8 6 4 2 Al ₂ O ₃ 40 40 40 40 40 40 40 40 40 40 40 -1mm ratio (%) 0 0 11 22 33 35 29 22 16 11 5

As can be seen through Experimental Examples 2 to 5, it can be seen that the content of Al ₂ O ₃ is more effective when less than 40%.

On the other hand, in the present embodiment, the experiment using the di- and tri-component dicalcium silicate, but the present invention is not limited to this, even when using a multi-component filler forming a dicalcium silicate, the same effect by the volume expansion due to phase transformation Will be readily understood by those skilled in the art.

1 is a schematic cross sectional view of a steel ladle carrying molten steel;

2 is an enlarged view of the outlet of the receiving ladle for carrying molten steel;

Figure 3 is an enlarged view of the discharge port in which the filler for the receiving ladle according to the present invention.

※ Explanation of code for main member of drawing ※

30: molten steel 70: well block

80: top nozzle 85: inert gas

90: fixing plate 91: first opening

100: sliding nozzle plate 101: second opening

110: shroud nozzle 111: third opening

300: filler

Claims (4)

In the filling ladle filler to be injected into the lower injection hole in the receiving ladle, The filler contains 60-72% CaO and 28-40% SiO ₂ by weight, and forms dicalcium silicate during use in the inlet, thereby reducing the volume by phase transformation of the dicalcium silicate upon cooling. A filler for a ladle, characterized in that to expand and differentiate to open the injection port. The method according to claim 1, The filler is a steel ladle filler by weight, containing 66% CaO and 34% SiO ₂ . In the filling ladle filler to be injected into the lower injection hole in the receiving ladle, The filler contains, by weight, 42-68% CaO, 4-36% SiO ₂ and 10-40% Al ₂ O ₃ , forming dicalcium silicate during use in the inlet. Filler for steel ladle, characterized in that the inlet opening is opened by volume expansion and differentiation by phase transformation of the dicalcium silicate during cooling. The method according to claim 1 or 3, And said cooling is carried out by an inert gas.

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