KR102036793B1 - Refractory indicator brick and steelmaking ladle using the same - Google Patents

Abstract

The present invention relates to a refractory indicator brick and a steel ladle having the same to determine the degree to which the refractory constructed in the steel bar used to take molten steel in the steelworks to be melted by the molten steel.

Description

Refractory indicator brick and steelmaking ladle using the same}

The present invention relates to a refractory indicator brick and a steel ladle having the same.

Steel mills deal with hot molten iron and molten steel during the steelmaking process, and in order to handle them, fire bricks that withstand high temperatures are used inside the steel structure, and the refractory is subjected to continuous physicochemical erosion by contact with molten iron and molten steel. do. Accordingly, the refractory is eroded continuously and wears out, and when worn out to a certain level, the refractory is dismantled and new refractories are constructed. However, if the refractory is replaced too early, the economic damage occurs, and if it is replaced too late, there is a risk of leakage of molten steel. Therefore, it is very important to accurately determine the remaining amount of refractory.

Conventionally, thermocouples are installed on the outside to determine the remaining amount of refractory, and the temperature is sensed, and the insulation thickness of the refractory is calculated by calculating the thickness of the refractory and the inside of the container is scanned by laser to measure the remaining amount of the refractory. The technique is known, but enormous investment costs are required.

In addition, there is a method of dividing the refractory index with the refractory lead to the shade of the refractory in the hot, but there is a risk of falling off the lead during the erosion by the molten iron and molten steel.

Korean Patent Publication No. 10-2013-0083906 (IPC: C21C 7/00, B22D 41/02, G01B 11/24) Korean Patent Publication No. 10-2012-0053867 (IPC: F27B 3/28, F27B 3/08, F27D 21/00)

The present invention is to provide a steel ladle having an indicator brick that can be distinguished quantitatively in five stages in order to solve the conventional problems as described above.

In another aspect, the present invention provides an indicator brick that can prevent the indicator from falling off due to the erosion caused by the molten iron and molten steel due to the large difference in erosion rate with the existing refractory.

In another aspect, the present invention is to provide an indicator brick that can be distinguished by the thickness difference of the refractory eroded at the molten iron temperature to determine the remaining amount of the refractory.

In order to achieve the above object, the steelmaking ladle according to an embodiment of the present invention in the steelmaking ladle sequentially provided from the outer shell, permanent field and refractory, the refractory is for measuring the residual thickness of the refractory Including an indicator brick, the indicator brick includes a brick base material and an indicator, the indicator is 50 to 80% by weight of magnesia (MgO), 5 to 35% by weight of chromium material, 8 to 15% by weight of carbon (C), And 1 to 10% by weight of an additive.

In the steel ladle according to an embodiment of the present invention, the chromium material may include any one or two or more selected from chromium oxide (Cr ₂ O ₃ ), magnesia chromium and chromite (Chromite). .

In the steelmaking ladle according to an embodiment of the present invention, the residual thickness of the refractory is determined according to the number of the indicator which is at least one indicator and exposed to the outside.

In the steelmaking ladle according to an embodiment of the present invention, a first indicator is built in a first position in the thickness direction of the indicator brick, the second indicator in a second position spaced apart from the first position in the thickness direction Characterized in that is built.

In the steel ladle according to an embodiment of the present invention, the brick base material and the indicator may independently include magnesia (MgO) and carbon (C).

The present invention also includes an indicator brick.

The indicator brick according to an embodiment of the present invention includes a brick base material and an indicator, wherein the indicator is 50 to 80% by weight of magnesia (MgO), 5 to 35% by weight of chromium material, and 8 to 15% by weight of carbon (C). , And 1 to 10% by weight of the additive.

In the indicator brick according to an embodiment of the present invention, the chromium material may include any one or two or more selected from chromium oxide (Cr ₂ O ₃ ), magnesia chromium and chromite.

In the indicator brick according to an embodiment of the present invention, the residual thickness of the refractory may be determined according to the number of the indicators having at least one indicator and exposed to the outside.

In the indicator brick according to an embodiment of the present invention, a first indicator is built in a first position in the thickness direction of the indicator brick, and a second indicator is built in a second position spaced apart from the first position in the thickness direction. Can be.

In the indicator brick according to an embodiment of the present invention, the center of the first indicator and the center of the second indicator may be spaced apart in the longitudinal direction of the indicator brick.

In the indicator brick according to an embodiment of the present invention, a first step in which the first and second indicators are not observed, a second step in which the first indicator is exposed, and a second in which the first and second indicators are exposed The remaining thickness of the refractory may be determined in step 3, a fourth step in which only the second indicator is exposed, and a fifth step in which the second indicator is not observed.

In the indicator brick according to an embodiment of the present invention, the brick base material and the indicator may independently include magnesia (MgO) and carbon (C).

As described above, the ladle having the indicator brick according to the present invention can be easily distinguished by the shade difference of the thickness of the refractory eroded at the molten steel temperature.

In addition, since the indicator brick according to the present invention exhibits a mutual erosion rate of the brick base material and the indicator within 10%, the brick base material and the indicator are lost to a similar size during erosion by the molten iron and molten steel, thereby preventing the indicator from falling off. Can be.

In addition, the indicator brick according to the present invention has the effect of quantifying the degree of erosion in each step according to the number of exposure of the indicator.

On the other hand, even if the effects are not explicitly mentioned herein, the effects described in the following specification expected by the technical features of the present invention and its provisional effects are treated as described in the specification of the present invention.

1 is a cross-sectional view of a steel ladle according to an embodiment of the present invention.
2 is a schematic diagram showing an eroded state of the indicator brick 310 according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail. The embodiments and drawings introduced below are provided as examples in order to sufficiently convey the spirit of the present invention to those skilled in the art. In addition, unless there is another definition in the technical and scientific terms used in the present invention, it has the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs, the present invention in the following description and the accompanying drawings Descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter will be omitted. Furthermore, various elements and regions in the drawings are schematically drawn. Therefore, the technical idea of the present invention is not limited by the relative size or spacing drawn in the accompanying drawings. In addition, unless otherwise indicated in this specification,% means weight%.

The present invention inserts a pair of indicators, which are refractory for residual determination, inside the indicator bricks, and inserts the pair of indicators with a step, so that the indicator bricks are eroded by the molten iron and the molten steel. To provide a ladle with indicator bricks that can be quantitatively distinguishable.

The present invention, unlike the prior art, by using the brick base material and the indicator including all the magnesia, because the degree of erosion has an erosion rate of less than 10%, the erosion by the molten iron and molten steel can be prevented from falling off the indicator It can provide excellent indicator bricks.

In addition, since the thickness of the refractory eroded at the molten steel temperature of about 1300 to 1700 ℃ can be distinguished by the shade difference, the present invention can provide an indicator brick that can easily determine the remaining amount of the refractory.

Conventionally, there has been disclosed a method of scanning the inside of a ladle using a laser or installing a thermocouple inside the ladle to determine the remaining amount of refractory, but this method has incurred enormous investment costs. In order to solve this problem, a method of dividing the refractory index of the refractory to low by the refractory shade in the hot has been attempted, but the problem that the refractory is dropped from the ladle during the erosion by the molten iron and molten metal.

According to the present invention, as a result of repeated studies and experiments to provide a more suitable refractory material in a high temperature environment such as the molten steel temperature, it is difficult to prevent detachment of the refractory material in a component system having a high chromium content, and a low chromium content. With the component system having a shade difference is insufficient to identify easily with the naked eye, it was completed through additional research and experiments to solve this problem.

Hereinafter, the steelmaking ladle according to the present invention will be described with reference to FIGS. 1 to 2.

1 is a cross-sectional view showing a steel ladle according to an embodiment of the present invention, and an enlarged perspective view of an indicator brick installed in a refractory.

Referring to Figure 1, the steelmaking ladle according to an embodiment of the present invention has a space for receiving the slag, the shell 100, the permanent field 200 and the refractory 300 is sequentially provided from the outside.

The refractory 300 accommodates the slag in the inner space.

The indicator brick 310 according to the present invention may be installed at a stop portion of the refractory 300 or a portion contacting the upper portion of the slag.

In detail, Figure 2 is a schematic diagram showing an eroded state of the indicator brick 310 according to an embodiment of the present invention.

The indicator brick 310 according to an embodiment of the present invention may determine whether the refractory 300 remains at the beginning of use, in use, or end of use according to the use time. In detail, the refractory 300 is removed from the inner side of the refractory 300 by erosion of slag. Since the refractory 300 and the indicator brick 310 contains a brick material of similar components, the erosion rate is similar to each other. Accordingly, the replacement time of the refractory 300 can be predicted according to the extent to which the indicator brick 310 is eroded.

For example, the brick base material 311 and the indicator 312 constituting the indicator brick 310 may include magnesia (MgO) and carbon (C). The brick containing magnesia (MgO) and carbon (C) is excellent in heat resistance, corrosion resistance and the like.

On the other hand, the indicator brick 310 according to an embodiment of the present invention may include a brick base material 311 and the indicator 312. As shown in FIG. 2, the indicator brick 310 has movable surfaces and remaining surfaces on both sides thereof, and erosion proceeds from the movable surfaces in contact with the slag described above.

At this time, in order to know the degree of erosion of the refractory 300, it may be formed by inserting a pair of indicator 312 in the indicator brick 310.

In addition, the indicator 312 may include a predetermined chromium material so as to absorb the light at the molten iron temperature to show the effect of the shade difference. That is, the indicator brick 310 can be seen that the above-mentioned refractory 300 is eroded by the indicator 312 containing the chromium material at the molten steel temperature.

In addition, the indicator brick 310 according to an embodiment of the present invention, in the thickness direction of the indicator brick 310 so as to determine whether the remaining of the refractory 300 in the beginning, in use, or end of use. And a pair of indicators 312 inserted into the pair of indicators 312 so that one of the indicators 312 of the pair of indicators 312 is inserted deeper than the other indicator so that the opposite surfaces face each other. Can be.

That is, the indicator brick 310 according to an embodiment of the present invention may determine the remaining thickness of the refractory 300 according to the number of the indicator that is at least one indicator and exposed to the outside.

That is, the first indicator 312-1 is embedded in the first position in the thickness direction of the indicator brick, and the second indicator 312-2 is embedded in the second position spaced apart from the first position in the thickness direction. Can be.

In addition, the center of the first indicator 312-1 and the center of the second indicator 312-2 may be spaced apart from each other in the longitudinal direction of the indicator brick 310.

Accordingly, the indicator brick 310 according to the present invention includes a first step in which the first and second indicators are not observed, a second step in which the first indicator 312-1 is exposed, and the first and second indicators. The remaining thickness of the refractory 300 is determined in a third step of exposing the indicator, a fourth step of exposing only the second indicator 312-2, and a fifth step in which the second indicator 312-2 is not observed. It can be determined.

Therefore, the indicator brick 310 according to the present invention enables the determination of the remaining amount of the refractory 300 described above according to the number and position of the indicator 312 is exposed.

In addition, the indicator 312 according to an embodiment of the present invention may include 5 to 35% by weight of chromium material so that it can be seen with the naked eye at a molten iron temperature.

The chromium material is not necessarily limited, but may include any one or two or more selected from chromium oxide (Cr ₂ O ₃ ), magnesia chromium and chromite to achieve the desired effect in the present invention. have.

In addition, the indicator 312 may include 50 to 80% by weight of magnesia (MgO), 8 to 15% by weight of carbon (C), and 1 to 10% by weight of additives to improve corrosion resistance and heat resistance at the molten iron temperature. Can be.

Hereinafter, the composition of the indicator 312 which is a preferable aspect of the present invention will be described.

Magnesia: 50-80 wt%

The magnesia is a material having heat resistance and corrosion resistance to maintain strength even at a high temperature of 1000 ° C or higher. When the magnesia is contained in 50 to 80% by weight, it does not soften even at high temperatures, maintains its original strength, and can withstand chemical effects. The content of magnesia may be included in 50 to 80% by weight, but preferably 60 to 80% by weight, more preferably 65 to 80% by weight, in order to improve the strength of the above-described brick base material and adhesion strength.

Chromium raw material: 5 to 35 wt%

In the present invention, the chromium-based raw material is added to exhibit a shade difference with the brick base material at a high temperature of about 1000 ° C. or more. Examples of the chromium material are not necessarily limited, but selected from chromium oxide (Cr ₂ O ₃ ), magnesia chromium (MgO-Cr ₂ O ₃ ) and chromite (Chromite) to achieve the desired effect in the present invention It may include any one or more than two.

In the present invention, the chromium-based raw material is included in 5 to 35% by weight, when the chromium-based raw material is less than 5% by weight, it is difficult to distinguish the brick base material and the shade difference. When the chromium material is more than 35% by weight, the indicator according to the present invention can be detached from the brick base material by erosion. The content of the chromium raw material may be included in 5 to 35% by weight, but preferably 10 to 35% by weight, more preferably 15 to 35% by weight in order to facilitate shading with the naked eye. .

On the other hand, according to another embodiment of the present invention, the indicator 312 may include 65 to 80% by weight of the magnesia. When the magnesia is included in an amount of 65 to 80 wt%, the indicator brick 310 according to the present invention may satisfy the following Equation 1.

[Relationship 1]

1 ≤ Erosion index ≤ 1.1

(Equation 1, the erosion index is B / A, A is the erosion amount of the brick base material 311, B is the erosion amount of the indicator 312.)

Carbon: 8-15 wt%

In the present invention, the carbon is added to improve the corrosion resistance of the indicator 312, wherein the carbon may be 8 to 15% by weight. If the amount of carbon added is less than 8% by weight, the corrosion resistance to molten steel is lowered, while if it exceeds 15% by weight, the consumption by oxidation of carbon increases, making it difficult to achieve the corrosion resistance to be achieved in the present invention.

In addition, the indicator 312 according to the present invention may include 1 to 10% by weight of the additive. The additive may include a binder and a metal component. When the additive is included in 1 to 10% by weight, it is possible to improve the moldability of the indicator 312 according to the present invention, and to suppress the oxidation of the above-described magnesia and chromium raw materials.

As a specific and non-limiting example, the binder may be a phenol resin. At this time, the phenol resin may be added in about 0.5 to 5% by weight.

As another specific and non-limiting example, the metal component may include aluminum, silicon, and the like. At this time, the metal component including aluminum and silicon may be added in about 0.5 to 5% by weight. In particular, the metal component may include 0.5 to 2.5% by weight of aluminum, and 0.5 to 2.5% by weight of silicon, but the present invention is not limited thereto.

The present invention will be described in more detail with reference to the following Examples. However, the following examples are merely examples of various embodiments of the present invention, and the present invention is not limited to the following examples.

(Examples 1-5, Comparative Examples 1-2)

As a raw material of the brick base material, the clay containing magnesia and carbon was shape | molded to width: 200 mm, length: 200 mm, height: 80 mm. A pair of indicators having the composition of Table 1 was inserted into the molded body. Subsequently, the molded body molded into the same component and size as the clay was placed on the molded body having an indicator inserted therein, and then pressed to produce an indicator brick in which the indicator was embedded.

Measurement Example 1

Shading Decision

The indicator bricks prepared in Examples and Comparative Examples were observed for 1 hour at 1400 ° C., and the colors (brightness) indicated by the indicators were visually observed and listed in Table 2 below. In addition, Table 2 lists whether the indicator is attached to the indicator brick under the same environment.

From this, MgO is preferably included in an amount of 65 to 80% by weight in order to improve the brick base material and the adhesion strength, and Cr ₂ O ₃ is preferably included in an amount of 15 to 35% by weight in order to facilitate shading with the naked eye. It can be seen.

Measurement Example 2

Erosion Experiment

The erosion index of the indicator bricks prepared in Examples and Comparative Examples was measured using a rotary erosion machine.

Specifically, the indicator brick was charged to a rotary erosion machine and then maintained at a temperature of about 1,600 degrees. Thereafter, Slag (slag) and Metal-Fe (metallic water) having a basicity of 2.86 were added at a weight ratio of 1: 1, and the rotary erosion machine was rotated for 50 minutes to proceed 1 cycle. After 14 cycles of performing 1 cycle 14 times, it was cooled to measure the erosion index of the eroded indicator brick. Next, the eroded indicator brick was cut, and the remaining thicknesses of the brick base material and the indicator were respectively measured from the cut surface of the indicator brick. The amount of erosion was obtained from the remaining thicknesses of the brick base material and the indicator, and the erosion index of the relational formula 1 was obtained. Here, the erosion amount is obtained by subtracting the thickness of the brick base material (or indicator) after erosion from the thickness of the initial brick base material (or indicator) before erosion.

Referring to Table 3, it can be seen from the Examples 1 to 5 that MgO is preferably contained at least 65% by weight in order to apply to steelmaking ladle considering the erosion index.

In the present invention as described above has been described by specific embodiments and limited embodiments and drawings, but this is only provided to help a more general understanding of the present invention, the present invention is not limited to the above embodiments, the present invention Those skilled in the art can make various modifications and variations from this description.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and all the things that are equivalent to or equivalent to the claims as well as the following claims will belong to the scope of the present invention. .

100: iron
200: permanent field
300: refractory
310: indicator brick
311: brick
312 indicator
312-1: first indicator
312-2: second indicator

Claims (12)

In the steelmaking ladle sequentially provided from the outside of the bark, permanent field and refractory,
The refractory includes an indicator brick for measuring the residual thickness of the refractory,
The indicator brick includes a brick base material and an indicator which absorbs light at a molten iron temperature inside the brick base material and shows an effect of shade difference.
The indicator is steel ladle comprising 65 to 75% by weight of magnesia (MgO), 15 to 20% by weight of chromium raw material, 8 to 15% by weight of carbon (C), and 1 to 10% by weight of the additive. .
The method of claim 1,
The chromium raw material is
Steelmaking ladle comprising any one or two or more selected from chromium oxide (Cr ₂ O ₃ ), magnesia chromium and chromite (Chromite).
The method of claim 1,
Steel ladle, characterized in that for determining the residual thickness of the refractory according to the number of the indicator is at least one indicator and exposed to the outside.
The method of claim 3,
The steel ladle, characterized in that the first indicator is built in a first position in the thickness direction of the indicator brick, the second indicator is built in a second position spaced apart from the first position in the thickness direction.
The method of claim 1,
The brick base material and the indicator ladle for steelmaking, characterized in that it comprises magnesia (MgO) and carbon (C) independently of each other.
In the indicator brick for measuring the residual thickness of the refractory provided in the steelmaking ladle,
The indicator brick includes a brick base material and an indicator which absorbs light at a molten iron temperature inside the brick base material and shows an effect of shade difference.
The indicator is an indicator brick, characterized in that it comprises 65 to 75% by weight of magnesia (MgO), 15 to 20% by weight of chromium raw material, 8 to 15% by weight of carbon (C), and 1 to 10% by weight of the additive.
The method of claim 6,
The chromium raw material is
Indicator brick comprising any one or more selected from chromium oxide (Cr ₂ O ₃ ), magnesia chromium and chromite (Chromite).
The method of claim 6,
And an indicator brick for determining a residual thickness of the refractory according to the number of the indicators having at least one indicator and exposed to the outside.
The method of claim 6,
The indicator brick is a first indicator is built in a first position in the thickness direction of the indicator brick, the second indicator is built in a second position spaced apart from the first position and the thickness direction.
The method of claim 9,
The center of the first indicator and the center of the second indicator is an indicator brick spaced apart in the longitudinal direction of the indicator brick.
The method of claim 10,
A first step in which the first and second indicators are not observed, a second step in which the first indicator is exposed, a third step in which the first and second indicators are exposed, and a fourth step in which only the second indicator is exposed And an indicator brick for determining a residual thickness of the refractory in a fifth step in which the second indicator is not observed.
The method of claim 6,
The brick base material and the indicator is an indicator brick containing magnesia (MgO) and carbon (C) independently of each other.

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