KR101356940B1 - Method for dipping slag sampler for sampling of slag - Google Patents

Abstract

The present invention relates to a method for dipping a slag sampler for collecting slag, the method for dipping a slag sampler for slag collecting according to the present invention is a method for dipping a slag sampler for collecting slag on the surface of molten steel in a vacuum atmosphere during the refining process of stainless steel, Setting a position of a ring pipe provided in the slag sampler body; And setting a holding time after the ring pipe is immersed in the slag.

Description

Method for dipping slag sampler for sampling of slag}

The present invention relates to a method for immersing a slag sampler for collecting slag, and more particularly, to a method for immersing a slag sampler for collecting slag without releasing vacuum during a refining process.

In general, the slag covering the molten steel surface is very important in the steelmaking process because it has a refining effect, such as desulfurization, delineation, heat insulation, inclusions removal effect. In order to perform this action, an appropriate amount of slag must be used. Therefore, it is necessary to extract the slag to know its composition and amount. For steelmaking operations operating in the atmosphere, slag is collected using a ladle-type slag sampler with a long handle. The slag collected is crushed into fine powder, melted by heating, processed into discs, and analyzed by XRF. In the vacuum process, it is impossible to use a ladle-type slag sampler, which is a general slag collection method, without releasing the vacuum by placing a ladle in the vacuum tank.

Therefore, conventionally, two types of slag collection methods are known which are used in vacuum refining. Both methods use a sub-lance, which is already installed on top of the vacuum refining vessel for sampling and temperature measurements.

The first is to use a disk-type slag sampler. Referring to FIG. 1A, a sampling disk 12 having a hole H formed in the lower portion of the slag sampler main body 11 is positioned so that the slag sampler 10 descends by the sub lance and passes through the slag 14. The slag 14 passes through the disc support 13 made of MgO and goes up through the hole H at the bottom of the disc 12 in the direction opposite to gravity (d), thereby removing the steel disc 12 having a hollow space in the middle. Filled up. Here, the disk 12 is composed of an upper cover 12a and a lower cover 12c and a disk body 12b accommodated therebetween.

The slag sampler 10 of this type is difficult to collect because the slag 14 does not flow into the disk 12 when the slag 14 is not completely liquefied. In addition, when the slag sampler main body 11 is immersed so deeply that the position of the disk 12 enters the molten steel 15, the heavy molten steel 15 pushes up the light slag 14 and the inside of the disk 12 is molten steel. Filled with (15). On the other hand, after being collected, it is already present in the same form as the disk 12, so it does not need to be processed into a fine powder and melted and processed into the same form as the disk 12, which has the advantage of being able to be immediately analyzed by XRF.

The second method is to use a ring pipe type slag sampler. Referring to FIG. 1B, a ring pipe 22 processed in a form in which a plurality of metal rings are sandwiched is attached to the slag sampler body 21. The slag sampler 20 of this type can be collected even when the slag 24 is not completely liquefied because the slag 24 is collected by being buried on the surface of the ring pipe 22. On the other hand, there is a difficulty in controlling the depth of immersing the sub lance so that the immersion is too shallow, the slag 24 is not collected, if the immersion too deep, the ring pipe 22 enters the interior of the molten steel (25) slag (24) ) Is not collected. In addition, since the temperature of the molten steel 25 at the time of collection is 1600 degreeC-1750 degreeC high temperature, when the ring pipe 22 enters inside the molten steel 25, it is likely to be lost.

The present invention has been made to solve the above problems, to provide a method for immersing the slag sampler for slag sampling without the release of the vacuum slag covering the molten steel surface located in the ladle of the vacuum tank during the refining process. For that purpose.

According to an embodiment of the present invention, a method of dipping a slag sampler for collecting slag is a method of dipping a slag sampler for collecting slag on the surface of molten steel in a vacuum atmosphere during a refining process of stainless steel, the position of the ring pipe provided in the slag sampler main body. Setting up; And setting a holding time after the ring pipe is immersed in the slag.

The ring pipe may be provided between one end and the other end of the slag sampler, and may include a plurality of ring pipes including at least a first ring pipe closest to the one end and a second ring pipe closest to the other end.

When the direction in which the ring pipe is immersed is called a gravity direction, the plurality of ring pipes including the first ring pipe and the second ring pipe may be provided at predetermined intervals along the gravity direction.

Prior to setting the position of the ring pipe, the method may further include setting a first length from a surface close to the one end to a surface close to the other end of the second ring pipe. In this case, the first length is preferably 15 cm or more.

In setting the position of the ring pipe, it is possible to set a second length from the other end to the surface close to the other end of the second ring pipe, wherein the second length is preferably in the range of 45cm or more and 60cm or less. Do.

In the step of setting the holding time, the holding time is preferably 1 second or more and 2 seconds or less.

According to the present invention, it is possible to provide a method of immersing a slag sampler which can collect slag covering the molten steel surface located in the ladle of the vacuum tank at one time without releasing the vacuum during the refining process.

In addition, the slag can be collected at a time without fail by setting the holding width in an appropriate range after immersing the entire width, the position of the ring pipe, the ring pipe, and the ring pipe of the ring pipe slag sampler.

1A and 1B are schematic diagrams schematically showing a different type of conventional slag sampling slag sampler.
Figure 2 is a flow chart schematically showing the dipping process of the slag sampler for slag collection according to an embodiment of the present invention.
Figure 3 is a schematic diagram showing a slag sampler for collecting slag according to an embodiment of the present invention.
4A and 4B are optical micrographs of a slag sampler according to Example 1 and Example 3 of the present invention, respectively.
5A and 5B are optical micrographs of a slag sampler according to Comparative Example 5 and Comparative Example 8 of the present invention, respectively.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. Means that a particular feature, region, integer, step, operation, element and / or component is specified, and that other specific features, regions, integers, steps, operations, elements, components, and / And the like.

Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Commonly used predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

Hereinafter, a method of immersing a slag sampler for collecting slag according to an embodiment of the present invention with reference to the drawings.

Figure 2 is a flow chart schematically showing the immersion process of the slag sampler for slag collection according to an embodiment of the present invention, Figure 3 is a schematic diagram showing a slag sampler for slag collection according to an embodiment of the present invention.

2 and 3, the immersion step of the slag sampler 100 for slag collection according to an embodiment of the present invention, the slag 130 for collecting the slag 130 on the surface of the molten steel 150 in a vacuum atmosphere during the refining process of stainless steel. A method of immersing a sampler (1000), comprising: setting a position of a ring pipe (120) provided in the slag sampler body (110) (S2); And setting the holding time after the ring pipe 120 is immersed in the slag 140 (S3).

Here, the ring pipe 120 is provided between one end 110a and the other end 110b of the slag sampler 100 and is closest to the first ring pipe 121 and the other end 110b closest to the one end 110a. It may be formed of a plurality including the second ring pipe 122.

Here, when the direction in which the ring pipe 120 is immersed is called the gravity direction g, the plurality of ring pipes 120 including the first ring pipe 121 and the second ring pipe 122 may have a direction of gravity ( It may be provided at regular intervals along g).

In addition, in the immersion method of the slag sampler 100 for slag collection according to the embodiment of the present invention, before the step of setting the position of the ring pipe 120, the first ring pipe 121 is one end (110a) And setting a first length L1 from the surface 121a proximate to the surface 122a to the surface 122a proximate the other end 110b. Here, it is preferable that the 1st length L1 is 15 cm or more.

Before setting the depth to immerse the slag sampler 100 having the ring pipe 120 in the state in which the slag 140 is made during the vacuum refining process, the height of the molten steel 150 must be known. The height of the molten steel 150 can be inferred through the weight and density of the molten steel 150 and the contents of the ladle (not shown), as is well known. However, depending on the number of times the ladle is used, it is common that the fire resistant material of the ladle inner wall may be molten or adhered to the ladle. Therefore, the entire width of the ring pipe 120 should be at least about 15cm long.

In addition, in setting the position of the ring pipe 120, the second length L2 from the other end 110b to the surface 122a proximate the other end 110b. Can be set. Here, it is preferable that 2nd length L2 is the range of 45 cm or more and 60 cm or less.

In the step of setting the position of the ring pipe 120 in the state where the slag 140 is made during the vacuum refining process, the position of the ring pipe 120 of the slag sampler main body 110 is the position of the molten steel 150 and the slag 140. It must be located at the interface. When the slag sampler 100 is immersed too deeply, the ring pipe 120 is lost. On the contrary, when the slag sampler 100 is immersed too low, the slag 140 is not collected in the ring pipe 120. In general, in order to take a molten steel sample and measure the temperature, the tip portion of the molten steel sampler is adjusted to be 50 cm below the molten steel surface. This should also be applied when collecting the slag 140 so that the depth to immerse the slag sampler 100 to be immersed 50cm lower than the general molten steel. Therefore, when setting the position of the ring pipe in the slag sampler main body 110, the surface 122a in which the second ring pipe 122 approaches the other end 110b is 45 cm or more from the other end 110b of the slag sampler main body 110. It is preferable to locate in the range of 60 cm or less.

In addition, in the step of setting the holding time after the ring pipe 120 is immersed in the slag 140, the immersion holding time is preferably 1 second or more and 2 seconds or less.

In the step of setting the time to maintain this after immersing the slag sampler 100, if the immersion is maintained for 6 seconds to 7 seconds, such as when the molten steel 150 is collected, the slag under the influence of the high temperature molten steel 150 in the proper position Since the ring pipe 120 of the sampler 100 is melted or the slag sampler main body 110 is burned and lost, the immersion holding time is preferably 1 second or more and 2 seconds or less.

< Comparative Example  And Example  >

Hereinafter, the present invention will be described in detail through comparative examples and examples.

In Table 1, the overall widths of the ring pipes of Comparative Examples 1-10 and Example 1-4, the distance from the slag sampler main body to the ring pipe, the immersion holding time, and whether the slag was collected are shown.

When deoxidizing general stainless steel into aluminum after decarburization in a VOD (Vacuum Oxygen Decarburization) refining process, a slag sampler 100 having a ring pipe 120 is formed 10 minutes after the slag 140 is deoxidized. The test was carried out using.

As can be seen in Table 1, when the overall width of the ring pipe 120, that is, 15cm and 20cm of the first length (L1) is 15cm or more, the second ring at the other end (110b) of the slag sampler body 110 When the second length L2 to the pipe 122 is in the range of 45 cm or more and 60 cm or less, and the immersion holding time for maintaining it after immersing the slag sampler 100 is 1 second or more and 2 seconds or less, the present invention of FIG. Slag sampling was possible as in the optical micrograph of the slag sampler according to Example 1 and the optical micrograph of the slag sampler according to Example 3 of the present invention of Figure 4b.

However, even if the overall width of the ring pipe is 15 cm or more, the holding time is 3 seconds or more (Comparative Examples 1, 2, 5) and the distance from the other end of the slag sampler main body to the surface where the second ring pipe of the second ring pipe is close to the other end. Less than 45 cm, the slag collection failed as the ring pipe disappeared as shown in the optical micrograph of the slag sampler of Comparative Example 5 of FIG. 5A.

Also, the optical microscope of the slag sampler of Comparative Example 8 of FIG. 5B also when the distance from the other end of the slag sampler main body to the surface where the second ring pipe of the second ring pipe is close to the other end exceeds 60 cm (Comparative Examples 7, 8). As shown in the photo, the slag did not come out on the ring pipe.

In addition, when the total width of the ring pipe was less than 15 cm (Comparative Examples 1 and 3), the amount of slag collected was small and difficult to analyze, and when the immersion holding time was 3 seconds or more (Comparative Examples 2 and 4), Lost.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be apparent to those skilled in the art that various modifications may be made without departing from the scope of the present invention.

Claims (8)

In the method of dipping the slag sampler for collecting slag on the molten steel surface in a vacuum atmosphere during the refining process of stainless steel,
The ring pipe is provided between one end and the other end of the slag sampler, and consists of a plurality of rings including at least a first ring pipe closest to the one end and a second ring pipe closest to the other end,
Setting a first length from a surface proximate said one end of said first ring pipe to a surface proximate said other end of said second ring pipe;
Setting a position of a ring pipe provided in the slag sampler body; And
A method of dipping a slag sampler for collecting slag, comprising the step of setting a holding time after the ring pipe is immersed in the slag. delete The method of claim 1,
When the direction in which the ring pipe is immersed is called a gravity direction, the plurality of ring pipes including the first ring pipe and the second ring pipe are provided at predetermined intervals along the gravity direction. Method of immersion of molten slag sampler. delete The method of claim 1,
The first length is more than 15cm immersion method of the slag sampler for slag extraction. 6. The method of claim 5,
In setting the position of the ring pipe,
A method of dipping the slag sampler for slag collection, setting a second length from the other end to the surface close to the other end of the second ring pipe. The method according to claim 6,
The second length is a immersion method of the slag sampler for slag collection in the range of 45cm or more and 60cm or less. The method of claim 1,
In setting the holding time,
The holding time is the immersion method of the slag sampler for slag collection is 1 second or less 2 seconds.

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