KR101044762B1 - Open nozzle of tundish with a function of preventing the formation of vortex of molten steel - Google Patents

Abstract

The present invention relates to a tundish open nozzle which can suppress the formation of molten steel vortex that can solve the injection instability caused by the molten steel vortex when the molten steel contained in the tundish in the continuous casting process is injected into the mold.

To this end, the present invention is a semi-conical shape is formed in a narrow narrow and the upper portion to be inserted and recessed in the tundish lower block 3, the molten steel inlet (4) is formed in the inner center, the molten steel inlet The molten steel vortex formation can be suppressed, characterized in that a plurality of vortex preventing grooves (1) formed at a predetermined interval around the molten steel inlet (4) to prevent the vortex phenomenon of the molten steel in the upper portion (4). It offers a tundish open nozzle.

As such, the present invention minimizes fluctuations in the surface of the infusion by injecting a stable mold and enables stable surface management, and contributes to the improvement of quality along with the prevention of facility accidents by the occurrence of regular oscillation marks, and the amount of scrap generated. Reduction can significantly reduce productivity and eliminate unproductive causes of performance.

Tundish, open nozzle, vortex prevention groove, molten steel inlet, molten steel injection

Description

Open-NOZZLE OF TUNDISH WITH A FUNCTION OF PREVENTING THE FORMATION OF VORTEX OF MOLTEN STEEL}

1 is a perspective view and a cross-sectional view of a molten steel injection state using a tundish and a tundish open nozzle conventionally used;

2 is a conceptual diagram illustrating a vortex generation situation due to rotational force during molten steel injection through a conventional open nozzle;

Figure 3 is a photograph of the unstable molten steel injection state due to the vortex phenomenon occurs when using a conventional open nozzle;

4 is a perspective view and a cross-sectional view of a tundish open nozzle capable of suppressing molten steel vortex formation according to the present invention;

5 is a plan view and a molten steel injection diagram showing a state in which a tundish open nozzle which can suppress vortex formation of molten steel according to the present invention is assembled to a tundish;

Figure 6 is a photograph of the molten steel injection flow state using a tundish open nozzle that can suppress the molten steel vortex formation according to the present invention;

7 is a graph comparing fluctuation deviations in the mold surface during injection of molten steel using the present invention and a conventional nozzle.

♣ Explanation of symbols for main part of drawing ♣                 

1: Vortex prevention groove 2: Open nozzle of the present invention 3: Turn dish block 4: molten steel inlet

100: molten steel 101: tundish 200: conventional open nozzle 201: conventional molten steel inlet

The present invention relates to a tundish open nozzle capable of suppressing vortex formation of molten steel, and more particularly, when injecting molten steel contained in a tundish in a continuous casting process into a mold, injection instability due to molten steel vortex can be solved. It relates to a tundish open nozzle capable of suppressing molten steel vortex formation.

In general, as illustrated in FIGS. 1 and 2, the open type tundish nozzle 200 used when injecting molten steel contained in the tundish into the mold may include the molten steel in the tundish 101. In the process of injecting 100 into the mold 102, the friction coefficient of the nozzle wall increases due to the shape of the fallopian tube model engraved in the center of the open nozzle type. The flow velocity deviation of the nozzle center part and the wall part is increased.

As a result, molten steel vortex (Vortex) is generated in the molten steel 100 injected into the mold 102 through the tundish nozzle 200, and due to the effect, the mold is in an unstable state (spreading phenomenon due to shaking). Is injected (see FIG. 3).

Due to the molten steel 100 injected into the mold 102 in an unstable state, irregular fluctuations in the surface frequently cause oscillation marks to be very unstable, causing the cast to be drawn and break-out and cast cracks. As cracks are generated, the amount of scrap is increased due to poor quality, and productivity is significantly reduced due to the occurrence of waiting time for recovering equipment accidents.

In particular, the molten steel fluctuation of the molten steel injected into the mold 102 in the continuous casting operation is automatically controlled by the sensor attached to the mold, but due to the irregular fluctuations frequently occurring, manual operation by the operator is inevitable and stable casting operation It is causing huge obstacles.

In order to solve the problems of the prior art as described above, the present invention is applied to the process of the molten steel in the tundish is injected into the mold by applying an open-type nozzle provided with a swirl prevention groove in the upper end of the nozzle center, preventing the swirl of the assembled nozzle The groove reduces the friction coefficient of the nozzle wall and reduces the flow velocity deviation between the nozzle center and the wall to prevent vortex or vortex, and minimizes the fluctuations of the molten steel injected into the mold due to the stability of the injection. The purpose of the present invention is to provide a tundish open nozzle which can prevent the formation of molten steel vortex that can perform stable casting work with quality improvement by preventing out and cracks.

In order to achieve the above object, the present invention is an open type nozzle for injecting molten steel contained in the tundish into a mold, the bottom is narrow and the upper portion is formed in a wide semiconical shape so as to be inserted and recessed in the tundish block A molten steel inlet is formed in the inner center of the molten steel, and a plurality of vortex preventing grooves are formed at regular intervals around the molten steel inlet to prevent the vortex of the molten steel on the upper portion of the molten steel inlet. Provides a tundish open nozzle with improved anti-shake performance.

In addition, the present invention is a tundish open nozzle capable of suppressing the molten steel vortex formation, characterized in that the molten steel inlet is formed in the upper portion is wide and narrow to the portion where the vortex prevention groove is formed, the lower portion is formed in a straight shape Will provide

In addition, the present invention is to provide a tundish open nozzle that can suppress the molten steel vortex formation, characterized in that the six vortex prevention groove is formed at intervals of 60 degrees around the molten steel inlet.

In addition, the present invention is inserted into the tundish block depth: the depth of the formation of the vortex preventing groove: the ratio of the depth of the straight molten steel inlet is formed in the ratio of 15: 40: 60 to suppress the vortex forming molten steel Provides a tundish open nozzle.

Hereinafter, the configuration of the present invention with reference to the accompanying drawings.

4 is a perspective view and a cross-sectional view of the tundish open nozzle that can suppress the molten steel vortex formation according to the present invention, Figure 5 is a tundish open nozzle that can suppress the molten steel vortex formation according to the present invention is assembled to the tundish It is a top view and molten steel injection figure which show the state.

The tundish open nozzle 2 capable of suppressing molten steel vortex formation according to the present invention is manufactured in the same shape as the conventional open nozzle 200.                     

However, the conventional open nozzle 200 is manufactured and used in a form in which the molten steel inlet 201 formed in the center portion becomes smaller in the shape of a straight line or a lower part, and thus it is not possible to suppress the occurrence of molten steel due to the rapid pressure drop caused by the molten steel discharge.

However, the tundish open nozzle 2 capable of suppressing the molten steel vortex formation according to the present invention is first inserted completely into the tundish lower block 3 as shown in FIG. Its appearance was changed to allow it to sink into depth.

That is, the conventional open nozzle 200 is formed so that the upper surface is located on the same line as the upper surface of the tundish lower block 3, the open nozzle 2 of the present invention is a tundish lower block (3) It is configured to facilitate the molten steel tapping by controlling the size so that the predetermined depth from the upper surface of the.

The outer shape of the open nozzle 2 according to the present invention is a semi-conical shape formed of a narrow bottom and a wide top.

A molten steel injection hole 4 into which molten steel is injected is formed at an inner center of the semi-conical shape.

On the upper portion of the molten steel inlet (4) is formed a plurality of vortex preventing grooves (1) to prevent the vortex phenomenon of the molten steel at regular intervals around the molten steel inlet.

That is, the vortex prevention groove (1) is formed in a plurality of intervals at a predetermined angle with respect to the molten steel inlet (4) looks like a flower shape.

Characteristic of the open nozzle (2) according to the present invention is the function of the vortex prevention groove (1) is the vortex prevention engraved on the upper portion of the nozzle center in the process in which the molten steel 100 in the tundish 101 is injected into the mold 102 The groove 1 reduces the friction coefficient of the nozzle wall surface and at the same time minimizes the flow rate deviation between the injection port 4 and the wall portion of the nozzle center to prevent the occurrence of molten steel vortex.

The mall vortex prevention groove (1) is formed with a plurality of predetermined angle intervals (45 to 90 degrees) centered around the molten steel inlet (4) is seen in the shape of a petal when viewed from the top, in this embodiment 60 degrees An open nozzle having six vortex preventing grooves 1 formed at intervals was used.

The more the vortex preventing groove 1, the more the vortex formation inhibiting ability of molten steel is improved, but the number of open nozzles 2, in which a larger number of vortex preventing grooves 1 are formed, shortens the life of the nozzle. It is preferable to form.

In addition, the present invention, as shown in the cross-sectional view of Figure 4, the depth (x) inserted into the tundish block (3): forming depth of the vortex preventing groove (1): the straight molten steel inlet The ratio of the depth z of (4a) was set to be 15:40:60.

As the depth x inserted and recessed in the tundish block 3 increases, the tapping speed of the molten steel increases more, but when the depth is formed too deeply, the tundish lower block 3 may result in severe erosion. The faster the speed, the shorter the life of the open nozzle 2, so the depth is determined in proportion to the total nozzle size.

In addition, the formation depth (y) of the vortex prevention groove (1) is a portion that is formed to have a fundamental function of preventing the vortex of the molten steel formed in the upper portion of the open nozzle (2), the depth should be shorter than the length of the nozzle lower portion Since molten steel can be stably injected into the mold, the depth of formation should be determined in proportion to the nozzle size.

Therefore, in the present invention, the depth (x) inserted into the tundish block 3 through a plurality of repetitive experiments (x): the forming depth of the vortex preventing groove 1 (y): of the straight molten steel inlet (4a) It was found that it is most preferable that the ratio z is formed to be 15:40:60.

Hereinafter, the operation of the present invention will be described.

6 is a photograph showing a molten steel injection flow state using a tundish open nozzle capable of suppressing the formation of molten steel vortex according to the present invention, Figure 7 is a variation in the mold surface during molten steel injection using the present invention and the conventional nozzle Is a graph comparing.

FIG. 6 prevents the vortex of the molten steel 100 injected through the open nozzle 2 of the present invention to prevent the shaking and spreading of the injection stream 105 injected into the mold 102 to perform stable molten steel injection. This is a picture of the ship.

FIG. 7 is a graph showing the fluctuation of the surface of the molten steel 100 injected into the mold 102 through the present invention and the open nozzle 2 and the open nozzle 200 used in the related art. Compared to the melt surface fluctuation of the molten steel injected into the mold 102 through the open nozzle (2) in which the vortex prevention groove 1 is formed according to the present disease, the variation of the melt surface injected into the mold 102 is more fine. (See Table 1).                     

As shown in Table 2, looking at the molten steel injection flow phenomenon according to the ratio of the depth (y) in which the vortex preventing groove (1) is formed and the depth (z) in which the straight molten steel inlet (4a) is formed, according to a preferred embodiment of the present invention Vortex prevention groove formation depth (y): The ratio of the formation depth (z) of the straight molten steel inlet (z) was found to be the best injection flow phenomenon when the ratio is 4: 6.

 As described above, the present invention prevents the vortex phenomenon of the molten steel injected into the mold in the tundish by using the open nozzle formed with the vortex prevention groove so that the molten steel can be stably injected into the mold without spreading or shaking of the injection stream.

In this way, stable mold injection of infusions minimizes fluctuations in the water surface, which enables stable water surface management, regular oscillation mark generation, and contributes to the improvement of quality along with the prevention of equipment accidents. It can contribute greatly to productivity by eliminating savings and non-productive causes of performance.

Claims (4)

In the open type nozzle for injecting molten steel contained in the tundish into a mold, It is coupled to the lower opening of the tundish block, the upper surface is disposed at a position lower than the bottom surface of the tundish block to form a step with the bottom surface of the tundish block, the lower surface is horizontal to the bottom of the outer surface of the tundish block A nozzle body formed in a semiconical shape having a narrow lower portion and a wider upper portion to be in close contact with the opening; A molten steel inlet formed in a central portion of the nozzle body along a length direction of the nozzle body, and having an inner diameter of an upper portion relatively larger than a lower portion thereof; And Is formed in the nozzle body so as to communicate with the molten steel inlet, it is formed including a plurality of vortex preventing grooves formed at a predetermined interval along the circumference of the molten steel inlet, The depth of formation of the vortex preventing groove is formed to be shorter than the length of the remaining portion of the molten steel inlet except for the portion connected in communication with the vortex preventing groove, and longer than the step depth formed by the bottom surface of the tundish block and the nozzle body. Tundish open nozzle, characterized in that formed. The method according to claim 1, The molten steel inlet (4) is a tundish open that can suppress the formation of the molten steel vortex, characterized in that the upper portion is wide and the lower portion is formed narrowly to the portion where the vortex prevention groove (1) is formed, the lower portion is formed in a straight shape Nozzle. The method according to claim 1, The vortex vortex prevention groove (1) is a tundish open nozzle that can suppress the vortex formation of the molten steel, characterized in that the six formed at intervals of 60 degrees around the molten steel inlet (4). delete

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