WO2021012201A1

WO2021012201A1 - Pneumatic swirling flow tundish for continuous casting

Info

Publication number: WO2021012201A1
Application number: PCT/CN2019/097403
Authority: WO
Inventors: 罗志国; 刘志远; 顾英杰; 杨伟栋; 邹宗树
Original assignee: 东北大学
Priority date: 2019-07-19
Filing date: 2019-07-24
Publication date: 2021-01-28
Also published as: CN110238375A

Abstract

A pneumatic swirling flow tundish for continuous casting. The pneumatic swirling flow tundish is composed of a tundish body (1) and an external tundish swirling flow chamber (2); the tundish body is communicated with the external tundish swirling flow chamber by means of a trench or groove (3); a plurality of inclined blowing air holes (4) are uniformly arranged in a side wall away a certain height from the bottom of the external tundish swirling flow chamber along the circumference, the trench or groove is positioned in the center of the tundish, the center surface of the trench or groove is coincided with the center surface of the tundish body and the external tundish swirling flow chamber; and the whole pneumatic swirling flow tundish is bilaterally symmetrical. The pneumatic swirling flow tundish for the continuous casting has the advantages of simple structure and low cost, and can implement the rotating flow of molten steel under the driving action of gas, and combines bubble impurity removal to improve the removal efficiency of inclusions in the tundish.

Description

Pneumatic swirl tundish for continuous casting

Technical field

The invention belongs to the technical field of continuous casting, and particularly relates to a pneumatic swirl tundish for continuous casting.

Background technique

In order to improve production efficiency, modern steel companies usually adopt continuous casting technology. In the continuous casting process, the molten steel in the tundish enters the mold through the sliding nozzle and the immersion nozzle, and the stopper rod and the sliding nozzle are used to achieve the amount of molten steel injected from the tundish to the mold and the flow of the molten steel in the mold. The control of behavior is of great significance for stable operation and guaranteeing the quality of slab. The removal of inclusions in the many metallurgical functions of the tundish has always been a part that metallurgists pay attention to. For molten steel continuous casting, the optimized design of the flow control device in the tundish plays an important role in the flow pattern, residence time and inclusion removal of molten steel.

In order to maximize the removal of inclusions in the tundish, metallurgical researchers have proposed many feasible technical measures, such as the use of flow control devices such as retaining walls and dams in the tundish, air curtain retaining walls in the tundish, and ladle nozzle blowing Argon, etc., these technologies are effective in the removal of large inclusions, but the removal efficiency of small inclusions is still low, and the venting bricks are complicated to manufacture, inconvenient to install, and easy to be blocked by molten steel.

In order to achieve the rotation of molten steel and the improvement of the removal rate of inclusions, the centrifugal tundish technology is proposed, which uses a magnetic field to rotate the molten steel in the cylindrical tundish and generate centrifugal force and huge turbulent energy to improve the deoxidation capacity and promote non-metal The floating and separation of inclusions, but the structure and operation of the electromagnetic cyclone device is more complicated, consumes electric power, and costs higher.

Based on the traditional turbulence controller and the design principle of the centrifugal tundish, the swirling tundish technology is proposed, that is, a swirling chamber is installed in the injection area of the ladle nozzle, and the molten steel flows into the swirling flow from the bottom of the swirling chamber in a tangential direction In order to achieve the purpose of transforming the potential energy of the molten steel into its rotational kinetic energy, the molten steel can rotate in the cyclone chamber to achieve a metallurgical effect similar to the centrifugal tundish. Although this method can make the molten steel spirally rise in the swirl chamber, extend the path of the molten steel in the tundish, and provide sufficient time for the inclusions to float; the rotation of the molten steel provides centripetal force for the inclusions, and the inclusions are under the action of the centripetal force Move to the center of the swirl chamber to promote the collision growth and floating removal of inclusions, but the swirl tundish structure is relatively complicated, and the ladle shroud outlet structure is L-shaped, which is difficult to produce and difficult to install and replace the ladle shroud.

Therefore, a pneumatic swirl tundish for continuous casting with simple structure, low cost and high inclusion removal efficiency is needed to solve the above problems. The structure consists of a tundish body and an external tundish swirl chamber. The inclined pores evenly arranged along the circumference at a certain height on the side wall of the swirl chamber are used for blowing. The blown argon gas drives the molten steel in the swirl chamber. The rotating flow combines the bubble removal of inclusions with the molten steel rotating flow, which greatly improves the removal efficiency of inclusions.

Summary of the invention

In view of the shortcomings of the prior art, the present invention provides a pneumatic swirl tundish for continuous casting, which has the advantages of simple structure and low cost. It can realize the rotating flow of molten steel under the driving action of gas, and combine with bubble removal. To improve the removal efficiency of tundish inclusions.

In order to overcome the defects in the prior art, the present invention adopts the following technical solutions:

A pneumatic swirl tundish for continuous casting is composed of a tundish body and an external tundish swirl chamber. The tundish body and the external tundish swirl chamber are connected by grooves or grooves. A number of inclined air blowing holes are evenly arranged along the circumference on the side wall at a certain height at the bottom of the swirling chamber. The height and inner diameter of the swirling chamber of the external tundish can be adjusted according to the actual situation.

The groove or groove between the tundish body and the external tundish swirl chamber is at the center of the tundish, and the center surface of the groove or groove is connected to the tundish body and the external tundish swirl chamber. The center planes coincide, and the aerodynamic swirl tundish is symmetrical.

The length of the groove or groove between the tundish body and the external tundish swirl chamber should be between 200mm-250mm, the width should be between 230mm-280mm, and the height should not be less than 200mm, according to actual conditions Need to be adjusted.

The height and inner diameter of the external tundish swirl chamber can be adjusted reasonably according to the capacity of the ladle and the continuous casting scale to ensure the smooth progress of the continuous casting work.

The blowing holes are evenly arranged along the circumference on the side wall of the external tundish swirling chamber, and their arrangement position on the sidewall of the external tundish swirling chamber should satisfy the horizontal centerline of the blowing holes to the bottom of the external tundish swirling chamber The distance is between 150mm-200mm, the number distributed along the circumference is 3-4, the aperture of the blowing hole is between 10mm-15mm, and the angle between the center line of the blowing hole and the horizontal direction of the tundish body is maintained at 45° Between -60°, the flow rate of argon in the blowing hole should be greater than the flow rate of molten steel in the ladle nozzle, and the specific parameters can be adjusted according to actual needs.

The arrangement position of the above-mentioned air blowing holes on the side wall of the external tundish swirl chamber should satisfy that the horizontal center line of the air blowing holes is higher than the exit position of the ladle shroud, and the ladle shroud is located in the center of the external tundish swirling chamber. .

Compared with the prior art, the beneficial effects of the present invention are:

(1) Compared with the traditional swirling tundish, the present invention installs the tundish swirling chamber on the outside of the tundish, and realizes the rotating flow of molten steel through gas drive, which promotes the collision and growth of inclusions, which is beneficial to the inclusion Float and remove.

(2) The argon gas blown into the swirling chamber of the external tundish adheres to the inclusions in the molten steel to complete the floating removal, which greatly improves the removal efficiency of the inclusions.

(3) Water model experiment and numerical simulation are performed on the aerodynamic swirling tundish of the present invention to verify the removal efficiency of inclusions. The results show that: compared with the traditional tundish, the aerodynamic swirling tundish has the removal efficiency of inclusions Significantly improved.

(4) The pneumatic swirl tundish according to the present invention has a simple structure and can be directly modified on the basis of the original tundish structure without changing the structure of the original tundish. For slabs, square billets, round billets, etc. Various process conditions can be universally used.

Description of the drawings

Figure 1 is a schematic diagram of the overall structure of a pneumatic swirl tundish for continuous casting of the present invention;

2 is a schematic diagram of the internal structure of a pneumatic swirl tundish for continuous casting of the present invention;

3 is a schematic diagram of the structure of an external swirl chamber of a pneumatic swirl tundish for continuous casting according to the present invention;

4 is a schematic diagram of the front sectional structure of a pneumatic swirl tundish for continuous casting of the present invention;

Figure 5 is a top view of a pneumatic swirl tundish for continuous casting of the present invention;

Figure 6 is a right view of a pneumatic swirl tundish for continuous casting of the present invention;

among them,

1- Tundish body; 2- External tundish swirl chamber; 3- Grooves or grooves; 4- Blow holes; 5- Ladle nozzles; 6- Tundish outlets.

Detailed ways

In order to better explain the present invention and facilitate understanding, the technical solutions and effects of the present invention will be described in detail below with reference to the accompanying drawings and through specific embodiments.

As shown in Figure 1 and Figure 2, a pneumatic swirl tundish for continuous casting is composed of a tundish body 1 and an external tundish swirl chamber 2, between the tundish body 1 and the external tundish swirl chamber 2. Connected by grooves or grooves 3, on the side wall at a certain height from the bottom of the external tundish swirl chamber 2, a number of inclined air blowing holes 4 are evenly arranged along the circumference. The arrangement of the air blowing holes 4 should meet the requirements for blowing The horizontal center line of the pores is higher than the exit position of the ladle shroud 5, which is located in the center of the external tundish swirl chamber 2.

The groove or groove 3 between the tundish body 1 and the external tundish swirling chamber 2 is at the center of the tundish, and the center surface of the groove or groove 3 is swirled with the tundish body 1 and the external tundish The center planes of the chamber 2 coincide, and the aerodynamic swirl tundish is symmetrical as a whole.

The length of the groove or groove 3 between the tundish body 1 and the external tundish swirl chamber 2 should be 200mm-250mm, the width should be between 230mm-280mm, and the height should not be less than 200mm. The size parameters can be adjusted according to actual needs. Reasonable size parameters can prevent the occurrence of drift phenomenon of the molten steel stream entering the tundish body 1 through the groove or groove 3; the height and inner diameter of the external tundish swirl chamber 2 should be To meet the needs of actual production, it can be adjusted reasonably according to the capacity of the ladle and the continuous casting scale to ensure the smooth progress of the continuous casting work.

A number of inclined air blowing holes 4 are evenly arranged along the circumference on the side wall of the external tundish cyclone chamber 2, and their arrangement position on the side wall of the external tundish cyclone chamber 2 should satisfy the horizontal centerline of the air blowing holes to the external tundish The distance between the bottom of the swirl chamber 2 is between 150mm-200mm, the number distributed along the circumference is 3-4, the pore diameter is between 10mm-15mm, and the angle between the centerline of the pore and the horizontal direction of the tundish body 1 is maintained at Between 45° and 60°, the flow rate of argon in the pores should be greater than the flow rate of molten steel in the ladle nozzle, and the specific parameters can be adjusted according to actual needs.

Example

Water model experiments and numerical simulations are used to study the metallurgical effect of the pneumatic swirl tundish described in this patent. The structure of the pneumatic swirl tundish used in the simulation research in the present invention is shown in Figures 1-3, and the size parameters are as follows As shown in Figure 4-6.

Among them, the top length L _{1 of the} tundish body 1 = 4180 mm, the width L ₄ = 1200 mm, the bottom length L _{2 of the} tundish body 1 = 3980 mm, the width L ₃ = 1000 mm, and the height of the tundish body 1 H ₁ = 1000 mm (the size shown is only It is the fluid area of the tundish, excluding the refractory material part); the inner diameter of the external tundish swirl chamber 2 is Φ ₁ =700mm, the outer diameter Φ ₂ =900mm, and the height H ₂ =800mm (excluding the refractory material part); The length of the groove or groove 3 between the package body 1 and the external tundish swirl chamber 2 is L=220mm, L'=240mm, width S=250mm, height H=200mm; the hole diameter of the blowing hole 4 is Φ ₃ ＝10mm, the angle between the center line of the air hole and the horizontal direction of the tundish body 1 is θ=45°, the vertical distance between the center line of the air hole and the bottom of the external tundish swirl chamber 2 H ₃ ＝200mm, the number of air holes is 3, each The angle between the center lines of the two air holes is 120°; the inner diameter of the ladle nozzle 5 is Φ ₄ ＝100mm, the outer diameter Φ ₅ ＝200mm, and the insertion depth of the nozzle H ₄ ＝700mm; the flow rate of molten steel is 1.5m/ s, the gas flow rate is 5m/s.

The molten steel enters the external tundish swirl chamber 2 from the ladle nozzle 5, and at the same time, the argon is blown by the inclined gas blowing holes 4 evenly arranged along the circumference on the side wall of the external tundish swirl chamber 2. The driving action causes the molten steel to spirally rise in the external tundish swirling chamber 2, flow into the tundish body 1 from the groove or groove 3, and finally flow into the mold from the tundish outlet 6. The process and results of the numerical simulation show that the structure not only achieves a good swirling effect, but also has no bias flow in the molten steel stream entering the tundish body 1 through the groove or groove. The most important thing is the inside of the tundish. The removal efficiency of inclusions is significantly improved.

The inclusions in the tundish are mainly Al ₂ O ₃ , and the removal rate is calculated by the following formula:

When using water model experiment, use the following formula to calculate:

Among them: η——Removal rate of inclusions in the tundish, %;

W _{Trap ——the} weight of the inclusions captured by the molten steel surface, kg;

W _{In ——weight} of inclusions added to molten steel, kg;

When using numerical simulation, use the following formula to calculate:

Among them: η——Removal rate of inclusions in the tundish, %;

N _{Trap ——the} number of inclusions captured by the molten steel surface, each;

N _In ——the number of inclusions added to the molten steel, each.

In this embodiment, the ANSYS finite element analysis software Fluent fluid analysis module is used for numerical simulation analysis, and the results obtained are shown in Table 1:

Table 1 Comparison of removal efficiency of inclusions (%)

It can be clearly seen from the numerical values in Table 1 that the removal rate of the pneumatic swirl tundish for continuous casting provided by the present invention is greatly improved compared with the traditional tundish.

Finally, it should be noted that the above descriptions are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall It is included in the protection scope of the present invention.

Claims

A pneumatic swirl tundish for continuous casting is composed of a tundish body and an external tundish swirl chamber, and is characterized in that: the tundish body and the external tundish swirl chamber are communicated with each other through grooves or grooves. A number of inclined air blowing holes are evenly arranged along the circumference on the side wall at a certain height from the bottom of the external tundish swirl chamber, and the height and inner diameter of the external tundish swirl chamber can be adjusted according to actual conditions.
The pneumatic swirling tundish for continuous casting according to claim 1, wherein the groove or groove between the tundish body and the external tundish swirling chamber is at the center of the tundish , The center surface of the groove or groove coincides with the center surface of the tundish body and the external tundish swirling chamber, and the aerodynamic swirling tundish is symmetrical.
The pneumatic swirling tundish for continuous casting according to claim 2, wherein the length of the groove or groove between the tundish body and the external tundish swirling chamber should be 200mm- Between 250mm, the width should be between 230mm-280mm, and the height should not be less than 200mm, which should be adjusted according to actual needs.
The pneumatic swirl tundish for continuous casting according to claim 1, characterized in that: the height and inner diameter of the external tundish swirl chamber can be adjusted reasonably according to the capacity of the ladle and the continuous casting scale to ensure The continuous casting work is proceeding smoothly.
The pneumatic swirling tundish for continuous casting according to claim 1, wherein the blowing holes are evenly arranged along the circumference on the side wall of the external tundish swirling chamber, which is on the side of the external tundish swirling chamber. The arrangement position on the wall should satisfy that the distance from the horizontal centerline of the blowing hole to the bottom of the external tundish swirl chamber is between 150mm-200mm, the number distributed along the circumference is 3-4, and the hole diameter of the blowing hole is 10mm Between -15mm, the angle between the center line of the blowing hole and the horizontal direction of the tundish body is maintained between 45°-60°. The flow rate of argon in the blowing hole should be greater than the flow rate of molten steel in the ladle nozzle. The specific parameters can be based on The actual demand is adjusted.
The pneumatic swirling tundish for continuous casting according to claim 5, characterized in that: the arrangement position of the blowing holes on the side wall of the swirling chamber of the external tundish should meet the horizontal centerline of the blowing holes. Higher than the exit position of the ladle shroud, the ladle shroud is located in the center of the swirling chamber of the external tundish.