阅读说明：本技术 一种分体式中间包湍流控制器 (Split type tundish turbulence controller ) 是由 卢金霖 罗志国 邹宗树 杨伟栋 赖卿锐 史本慧 于 2020-11-19 设计创作，主要内容包括：一种分体式中间包湍流控制器,包括中间包本体和外置控流区两部分。外置控流区包括控制器上部、控制器下部以及腔室。本发明通过在外置控流区加入湍流控制器,使钢液从长水口进入湍流控制器,冲击底部控制器下部产生强烈向上回流,而后由控制器上部挡住向上冲击的钢液流,使之向下沿外置控流区底部流动,而后从湍流控制器与外置控流区壁面之间向上流出外置控流区,最后流向中间包本体。本湍流控制器一方面削弱钢液的湍流强度降低湍动能,降低了钢液对渣金界面的冲击；另一方面能削弱钢液进入中间包主体的速度,增大活塞流体积,减少死区体积,提高钢液的停留时间,为夹杂物去除创造良好的流场,更有利于夹杂物的上浮去除。(A split tundish turbulence controller comprises a tundish body and an external flow control area. The external flow control area comprises an upper controller part, a lower controller part and a chamber. According to the invention, the turbulence controller is added in the external flow control area, so that molten steel enters the turbulence controller from the long nozzle, the lower part of the bottom controller is impacted to generate strong upward backflow, the upward impacting molten steel flow is blocked by the upper part of the controller and flows downwards along the bottom of the external flow control area, and then the molten steel flows out of the external flow control area from the space between the turbulence controller and the wall surface of the external flow control area and finally flows to the tundish body. On one hand, the turbulence controller weakens the turbulence intensity of the molten steel, reduces the turbulence energy and reduces the impact of the molten steel on a slag-metal interface; on the other hand, the speed of molten steel entering the tundish body can be weakened, the volume of piston flow is increased, the volume of dead zones is reduced, the residence time of the molten steel is prolonged, a good flow field is created for removing inclusions, and the floating removal of the inclusions is facilitated.)

1. The split tundish turbulence controller is characterized by comprising a controller upper part, a cavity, a controller lower part and an external flow control area, wherein the external flow control area is connected with a tundish body through a groove, the external flow control area is of a cylindrical structure with an opening at one end, the controller lower part is arranged on the upper surface of a bottom plate of an external flow control area, the controller upper part is arranged above the controller lower part, the cavity is formed between the controller upper part and the controller lower part, a long water gap communicated with the controller upper part is arranged at the top of the controller upper part, the controller upper part and the long water gap are integrally formed, and the long water gap is connected with a steel ladle outlet.

2. The split tundish turbulence controller of claim 1, wherein: the tundish body is of an open square structure, tundish outlets are formed in two ends of a bottom plate of the tundish body, a boss is formed in the middle of the bottom plate and protrudes inwards, the boss is located between the two tundish outlets, blocking dams are arranged along wide edges of the boss, retaining walls are symmetrically arranged between the two blocking dams, and the end portions of the retaining walls are connected with the inner side surface of a long plate of the tundish body.

3. The split tundish turbulence controller of claim 1, wherein: the long nozzle, the upper part of the controller and the lower part of the controller are positioned on the same central line; the inner surface of the upper part of the controller is a circular table surface, and an included angle theta between the inner surface of the upper part of the controller and the axis of the long nozzle₁0-30 degrees, the inner surface of the lower part of the controller is a circular table surface, and the included angle theta between the inner surface of the lower part of the controller and the axis of the long nozzle₂Is 0 to 30 degrees.

4. The split tundish turbulence controller of claim 1, wherein: the height H of the lower part of the controller₃Not more than chamber height H₄One half of (c), controller upper height H₂>Height H of chamber₄One half of (d), controller lower height H₃And the height H of the upper part of the controller₂The sum being the chamber height H₄0.9-1.3 times of the height of the chamber H₄Less than or equal to the height H of the cylindrical part of the external flow control area₁One half of (a).

5. The split tundish turbulence controller of claim 1, wherein: the diameter d of the lower part of the controller₃Is greater than the diameter d of the long nozzle₁Twice the diameter d of the upper part of the controller₂Is larger than the diameter d of the lower part of the controller₃Is one half to three times and the square d of the internal diameter of the external flow control area₆ ²Is larger than the square d of the diameter of the upper part of the controller₂ ²Twice as much.

6. The split tundish turbulence controller of claim 2, wherein: included angle theta between the side wall of the groove and the tundish body₃75 to 90 degrees; the central plane of the groove is superposed with the central planes of the tundish body and the external flow control area, the vertical section of the groove is rectangular, and the sectional area is adjusted according to the molten steel flow rate of the water gap and the sectional area of the water gap.

7. The split tundish turbulence controller of claim 1, wherein: the upper part of the controller and the long water gap are made of refractory materials with high erosion resistance and service life.

8. The split tundish turbulence controller of claim 1, wherein: the upper part and the lower part of the controller are cylindrical or cubic.

Technical Field

The invention belongs to the technical field of continuous casting, and particularly relates to a split tundish turbulence controller.

Background

Modern steel enterprises generally adopt a continuous casting technology in order to improve production efficiency. In the continuous casting process, molten steel in a tundish enters a crystallizer through a sliding water gap and a submerged nozzle, and the stopper rod and the sliding water gap are matched to control the injection amount of the molten steel from the tundish to the crystallizer and the flowing behavior of the molten steel in the crystallizer, so that the method has very important significance for stable operation and casting blank quality guarantee. The degree of inclusion removal in the many metallurgical functions of the tundish has been a significant concern for metallurgists. For continuous casting of molten steel, the optimal design of the flow control device in the tundish plays an important role in the flow mode, the residence time, the inclusion removal and the like of the molten steel.

The flowing state of the molten steel has great influence on the removal of the impurities, and the flowing of the molten steel in the steel ladle is mainly divided into piston flow, complete mixed flow and dead zones. The larger the volume of the dead zone is, the smaller the effective volume of the ladle is, and the shorter the retention time of the molten steel is, so that the floating removal of impurities is not facilitated; the larger the volume of the piston flow is, the more stable the molten steel flows in the steel ladle, and the floating removal of impurities is facilitated. The tundish usually adopts measures such as a turbulence controller, a retaining wall dam, an air curtain retaining wall and the like to optimize a molten steel flow field, and the methods can improve the flow of the molten steel to a certain extent, reduce a dead zone of the molten steel and improve the retention time of the molten steel. However, these methods have limited improvement in the flow field of the injection zone and placing turbulence controllers in the tundish has a greater impact on the ladle slag-metal interface.

In recent years, a design concept of a split tundish is provided, namely a flow control area is arranged outside the tundish and is connected with a tundish main body through a groove, so that the turbulent flow of molten steel is controlled in the external flow control area, and the influence of the molten steel flow injected through a long nozzle on the whole flow field of the tundish is weakened. Molten steel enters the external flow control area through the long nozzle, the flow velocity of the molten steel is reduced by a series of methods, the volume of the piston flow area is increased, the volume of a dead zone is reduced, the residence time of the molten steel is increased, and floating removal of inclusions is facilitated.

Disclosure of Invention

The invention aims to solve the problems in the prior art, and aims to provide a molten steel turbulence energy dissipation device which is simple in structure, simple and convenient to machine and operate, capable of dissipating the turbulence energy of molten steel in an external flow control area, reducing the flow velocity of the molten steel entering a tundish, avoiding molten steel splashing and molten steel exposure, improving the piston flow volume of the tundish, prolonging the retention time of the molten steel and creating good conditions for floating and removing inclusions.

In order to achieve the purpose, the invention adopts the following technical scheme:

a split tundish turbulence controller comprises a controller upper portion, a cavity, a controller lower portion and an external flow control area, wherein the external flow control area is connected with a tundish body through a groove, the external flow control area is of a cylindrical structure with an opening at one end, the controller lower portion is arranged on the upper surface of a bottom plate of an external flow control area, the controller upper portion is arranged above the controller lower portion, the cavity is formed between the controller upper portion and the controller lower portion, a long nozzle communicated with the controller upper portion is arranged at the top of the controller upper portion, the controller upper portion and the long nozzle are integrally formed, and the long nozzle is connected with a steel ladle outlet.

The tundish body is of an open square structure, tundish outlets are formed in two ends of a bottom plate of the tundish body, a boss is formed in the middle of the bottom plate and protrudes inwards, the boss is located between the two tundish outlets, blocking dams are arranged along wide edges of the boss, retaining walls are symmetrically arranged between the two blocking dams, and the end portions of the retaining walls are connected with the inner side surface of a long plate of the tundish body.

The long nozzle, the upper part of the controller and the lower part of the controller are positioned on the same central line. The inner surface of the upper part of the controller is a circular table surface, and an included angle theta between the inner surface of the upper part of the controller and the axis of the long nozzle₁0-30 degrees, the inner surface of the lower part of the controller is a circular table surface, and the included angle theta between the inner surface of the lower part of the controller and the axis of the long nozzle₂Is 0 to 30 degrees.

The height H of the lower part of the controller₃Not more than chamber height H₄One half of (c), controller upper height H₂>Height H of chamber₄One half of (d), controller lower height H₃And the height H of the upper part of the controller₂The sum being the chamber height H₄0.9 to 1.3 times of the total amount of the active ingredient. ChamberHeight H₄Less than or equal to the height H of the cylindrical part of the external flow control area₁And one half of the total height of the external flow control area, wherein the height of the external flow control area is adjusted according to actual needs.

The diameter d of the lower part of the controller₃Is greater than the diameter d of the long nozzle₁Twice the diameter d of the upper part of the controller₂Is larger than the diameter d of the lower part of the controller₃Is one half to three times and the square d of the internal diameter of the external flow control area₆ ²Is larger than the square d of the diameter of the upper part of the controller₂ ²Twice as much. External flow control area inner diameter d₆And the height H of the cylindrical part of the external air flow area₁According to the size of the tundish.

Included angle theta between the side wall of the groove and the tundish body₃75 to 90 degrees; the central plane of the groove is superposed with the central planes of the tundish body and the external flow control area, the vertical section of the groove is rectangular, and the sectional area is adjusted according to the molten steel flow rate of the water gap and the sectional area of the water gap.

The upper part of the controller and the long water gap are made of refractory materials with high erosion resistance and service life.

The upper part and the lower part of the controller are cylindrical or cubic.

Compared with the prior art, the invention at least comprises the following beneficial effects:

1. compared with the traditional rotational flow tundish, the tundish rotational flow chamber is arranged on the outer side of the tundish, the tundish is divided into a turbulence area and a steady flow area, the turbulent energy dissipation of molten steel is concentrated in the external flow control area, and the inclusions promote the collision polymerization of the inclusions to grow under the action of the turbulent energy of the molten steel; in the tundish body, the flow of molten steel is stable, the residence time is longer, and floating removal of inclusions is facilitated.

2. The split tundish turbulence controller provided by the invention is subjected to numerical simulation to verify the flowing state of molten steel, and the result shows that: compared with the traditional tundish, the turbulence controller has the advantages that the change of a molten steel flow field is obvious, the volume of a piston flow area is increased, and a dead zone is reduced.

3. The numerical simulation is carried out on the split tundish turbulence controller to verify the removal efficiency of the inclusions, and the result shows that: compared with the traditional tundish, the efficiency of removing the impurities in the pneumatic cyclone tundish is obviously improved.

4. The split tundish turbulence controller provided by the invention has a simple structure, can be directly reconstructed on the basis of the original tundish structure, does not need to change the original tundish structure, and is matched with a retaining wall dam, an air curtain retaining wall, a long nozzle argon blowing and the like to better optimize a tundish flow field.

5. Molten steel enters the bottom of the impact controller from the water gap, and the controller bottom device is arranged at the bottom of the impact controller, so that the flowing of the molten steel is more uniform and stable, the dissipation rate of turbulent kinetic energy of the molten steel is greatly increased, and the turbulent kinetic energy is mainly dissipated in the controller. The upper control device can restrain the molten steel flowing upwards from the lower control device, and the speed of the molten steel flowing out from the controller is greatly reduced, so that the impact of the molten steel on the molten steel surface of the slag metal is greatly weakened, and slag entrapment is reduced.

Drawings

FIG. 1 is a schematic diagram of a split tundish turbulence controller according to the present invention;

FIG. 2 is a schematic diagram of an external flow control area of the split tundish turbulence controller of the present invention;

FIG. 3 is a top view of the split tundish turbulence controller of the present invention;

FIG. 4 is a cross-sectional view of the external flow control zone of the split tundish turbulence controller of the present invention;

FIG. 5 is an overall cross-sectional view of the split tundish turbulence controller of the present invention;

1-long water gap; 201-controller upper part; 202-controller lower part; 203-a chamber; 3-external flow control area; 4-a groove; 5-tundish outlet; 6, blocking a dam; 7-retaining wall; 8-tundish body.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

As shown in fig. 1 to 5, a split tundish turbulence controller comprises an upper controller portion 201, a chamber 203, a lower controller portion 202 and an external flow control portion 3, wherein the external flow control portion 3 is connected with a tundish body 8 through a groove 4, the external flow control portion 3 is a cylindrical structure with an open end, the lower controller portion 202 is arranged on the upper surface of a bottom plate of an external flow control portion, the upper controller portion 201 is arranged above the lower controller portion 202, the chamber 203 is formed between the upper controller portion 201 and the lower controller portion 202, a long nozzle 1 communicated with the upper controller portion 201 is arranged at the top of the upper controller portion 201, the upper controller portion 201 and the long nozzle 1 are integrally formed, and the long nozzle 1 is connected with a ladle outlet.

The tundish body 8 is of an open square structure, tundish outlets 5 are formed at two ends of a bottom plate of the tundish body 8, a boss is formed in the middle of the bottom plate and protrudes inwards and is located between the two tundish outlets 5, blocking dams 6 are arranged along wide edges of the boss, retaining walls 7 are symmetrically arranged between the two blocking dams 6, and the end portions of the retaining walls 7 are connected with the inner side surface of a long plate of the tundish body 8.

The long nozzle 1, the controller upper part 201 and the controller lower part 202 are positioned on the same central line. The inner surface of the upper part 201 of the controller is a circular table surface, and an included angle theta between the inner surface of the upper part 201 of the controller and the axis of the long nozzle 1₁Is 0-30 degrees, the inner surface of the lower part 202 of the controller is a circular table surface, and the included angle theta between the inner surface of the lower part 202 of the controller and the axis of the long nozzle 1₂Is 0 to 30 degrees.

The height H of the lower part 202 of the controller₃Less than or equal to the height H of the chamber 203₄One-half of the height H of the controller upper portion 201₂>Height H of chamber 203₄One-half of (c), height H of controller lower portion 202₃And the height H of the controller upper part 201₂The sum of which is the height H of the chamber 203₄0.9-1.3 times of the height H of the chamber 203₄Less than or equal to the height H of the cylindrical part of the external flow control area 3₁One half of (a). The height of the external flow control area 3 is adjusted according to actual needs.

The diameter d of the controller lower portion 202₃Is larger than the diameter d of the long nozzle 1₁Twice the diameter d of the controller upper portion 201₂Is larger than the diameter d of the lower part 202 of the controller₃Is a factor of two to three and the square d of the inner diameter of the outer flow control zone 3₆ ²Is larger than the square d of the diameter of the upper part 201 of the controller₂ ²Twice as much. External flow controlZone 3 internal diameter d₆And the height H of the cylindrical part of the external air flow area₁According to the size of the tundish.

The included angle theta between the side wall of the groove 4 and the tundish body 8₃75 to 90 degrees; the central plane of the groove 4 is superposed with the central planes of the tundish body 8 and the external flow control area 3, the vertical section of the groove 4 is rectangular, and the sectional area is adjusted according to the flow rate of molten steel at the water gap and the sectional area of the water gap.

The controller upper part 201 and the long nozzle 1 are made of refractory materials with high erosion resistance and service life.

The controller upper part 201 and the controller lower part 202 are cylindrical or cubic in shape.

Example 1

The metallurgical effect of the split tundish turbulence controller is researched by applying water model experiments and numerical simulation, and the length L of the top of the tundish body 8₆5500mm, width L₄1400mm, the length L of the bottom of the tundish body 8₅5000mm, width L₃1200mm, tundish body 8 height H₅1300mm (the dimensions shown are only the flow area of the tundish, containing no refractory parts); internal diameter d of external flow control device₆700mm, height H₁800 mm; the length D of the groove 4 between the tundish body 8 and the external flow control area 3 is 550mm, and the included angle theta between the side wall of the groove 4 and the tundish body 8₃90 DEG, height H₆200 mm; inner diameter d of long nozzle 1₁100mm, height H of controller upper portion 201₂110mm, and angle theta₁20 °, controller lower portion 202 height H₃90mm, and included angle theta₂20 °; height H of chamber 203₄200 mm. The flow rate of molten steel in the simulation process is 1 m/s.

Molten steel enters the external flow control area 3 from the long nozzle 1, impacts the lower part 202 of the controller, then flows back upwards to impact the upper part 201 of the controller, flows downwards under the blocking of the upper part 201 of the controller to impact the bottom of a steel ladle, then flows upwards along a channel between the upper part 201 of the controller and the ladle wall of the external flow control area 3, enters the tundish body 8 through the groove 4, and finally flows into the crystallizer from the outlet 5 of the tundish. The numerical simulation process and the results show that the structure not only reduces the volume of dead zones and improves the volume of piston flow, but also has small and uniform flow velocity of molten steel entering the tundish body 8 through the groove 4, and the most important is that the removal efficiency of inclusions in the tundish is obviously improved.

ANSYS finite element analysis software Fluent is used for simulating the molten steel flow characteristic of the external flow control area 3, a tracer is added to the upper portion of a water gap, the concentration of the tracer is monitored at the joint of the chute and the tundish body 8, the RTD curve of the external flow control area 3 can be obtained, the fluid flow condition can be calculated through the RTD curve, and the calculation result is shown in table 1.

Theoretical average residence time:

t_a＝V/Q

plug flow residence time:

t_p＝(t_min+t_peak)/2

average residence time:

t_1c＝∑tC(t)/∑C(t)

t∈[0,+∞)

twice the average residence time:

t_2c＝∑tC(t)/∑C(t)

t∈[0,2t_a]

plug flow volume fraction:

V_p＝t_p/t_a

dead zone volume fraction:

V_d＝1-t_1c/t_2c

mixed flow volume fraction:

V_m＝1-V_p-V_d

in the formula: v-external control chamber molten steel volume m³(ii) a Q-molten steel volume flow, m³/s；t_min-is the exit tracer response time, s; t is t_peak-is the tracer peak time, s; t-is the exit monitoring time, s; and C (t) -t time dimensionless concentration of tracer.

TABLE 1 external current control region RTD Curve analysis

Item	ta	tp	t1c	t2c	Vp	Vd	Vm
								Without controller	43.47	5.85	42.20	35.8	0.13	0.15	0.72
Traditional controller	42.59	13.87	48.36	38.3	0.32	0.21	0.47
								Novel controller	42.13	18.20	42.40	38.2	0.43	0.10	0.47

Wherein: t is t_a-a theoretical mean residence time; t is t_p-plug flow residence time; t is t_1c-average residence time; t is t_2c-2 times the average residence time; v_p-plug flow volume fraction; v_d-dead space volume fraction; v_m-mixed flow volume fraction;

as can be seen from the data in Table 1, the plug flow volume of this patent is greater than the conventional controller and no controller and the dead volume is also less than the conventional controller and no controller.

The inclusions in the tundish are mainly Al₂O₃Mainly, the removal rate is calculated by the following formula:

when using the water model experiment, the following formula is used for calculation:

wherein: eta-removing rate of impurities in the tundish,%; w_Trap-the weight of inclusions captured at the molten steel surface, kg; w_In-the weight of inclusions added to the molten steel, kg;

when numerical simulations are used, the following calculation is used:

wherein: eta-removing rate of impurities in the tundish,%; n is a radical of_Trap-the number of inclusions captured at the molten steel surface; n is a radical of_InThe number of inclusions added to the steel melt.

In this embodiment, an ANSYS finite element analysis software Fluent fluid analysis module is used to perform numerical simulation analysis, and the obtained results are shown in table 2:

table 2 comparison of impurity removal efficiency (%)

As can be seen from the data in Table 2, the removal rate of the inclusions with the grain sizes of 40 um, 50 um, 60 um and 70um in the tundish is respectively improved by 26.7%, 35%, 25.5% and 3.1% compared with the traditional controller, wherein the removal rate of the inclusions with the grain sizes of 70um is as high as 98.8%.