CN111266564A - Device for limiting generation of steel ladle vortex and application thereof - Google Patents

Abstract

The invention discloses a device for limiting the generation of ladle vortex and its application, and belongs to the technical field of ladle tapping of metallurgical reactors. In view of the fact that vortices will be generated in the metallurgical device in the final stage of ladle pouring during the steelmaking process, resulting in the phenomenon of slag entrainment, and the existing technology forces the closure of the nozzle when slag entrainment occurs, resulting in the waste of remaining molten steel in the ladle. The invented vortex blocking device is based on the principles of Coriolis force and fluid mechanics, and a vortex blocking device made of refractory material is arranged above the nozzle of the ladle where the tapping phenomenon occurs to limit the formation of the vortex flow field, thereby inhibiting the generation of vortices. At the same time, the movement direction of the fluid near the outlet is changed, which greatly reduces the height of molten steel produced by the vortex, delays the time of whirlpool, reduces the height of whirl and penetration by 90‑100%, increases the yield of molten steel, prevents slag, and improves tapping quality, reducing production costs.

Description

A device for limiting the generation of ladle vortex and its application

technical field

The invention relates to the technical field of ladle tapping in metallurgical reactors, and more particularly, to a device for limiting the generation of ladle vortex and its application.

Background technique

With the development of society and technology, the requirements for steel quality are getting higher and higher. In order to obtain high-quality steel, it is necessary to control the inclusions in the steel and reduce the content of impurity elements in the steel. Therefore, it is necessary to strictly control the quality of molten steel in each metallurgical link. In the modern steelmaking process, when molten steel is transferred from one metallurgical reactor to another metallurgical reactor, the phenomenon of vortex slag entrainment is a problem that has been difficult to completely solve for a long time, which makes it difficult to remove the inclusions in the steel and seriously affects the molten steel. quality. At the end of pouring from the ladle to the tundish, the steel slag is involved in the molten steel. On the one hand, the steel remains in the ladle and the yield is reduced; on the other hand, the steel slag will enter the long nozzle and the downstream metallurgical reactor. Cause serious impact, not only increase the production cost, but also bring tedious work to the on-site cleaning.

In order to prevent a large amount of steel slag from entering the downstream metallurgical reactor, manual visual inspection or installation of a slag monitoring device is usually used on site. When the steel slag is about to enter the long nozzle, the nozzle is forcibly closed. At this time, the remaining molten steel in the ladle cannot be used and is wasted. At the end of ladle pouring, the rotation of the earth will cause Coriolis force, which will lead to the formation of vortices, which will lead to slag entrainment, that is, when molten steel is not poured completely, slag entrainment will occur. At this time, the forced closing of the nozzle will inevitably lead to the residual molten steel in the ladle. Can't be used in ladle. On the whole, the existing technology cannot completely suppress the generation of vortices, and there is still residual steel after the metallurgical device has finished tapping, which reduces the metal yield. Therefore, it is necessary to design a device with simple structure and easy realization to effectively suppress the generation of vortex in the metallurgical device in the later stage of tapping.

After searching, the Chinese patent application number: ZL200910187709.6, the name of the invention is: anti-swirl device for reducing fluid vortex, the application date is: September 29, 2009, the application provides a device for hindering the generation and development of fluid vortices , the device places one or several tables made of corrosion-resistant refractory materials near the nozzle at the bottom of the ladle or tundish. The generation of the vortex cannot be completely suppressed, so that the height of the vortex cannot be reduced well, and the phenomenon of slag entrainment will continue to occur.

SUMMARY OF THE INVENTION

1. The technical problem to be solved by the invention

In view of the existing steelmaking process, there will be vortices in the metallurgical device in the final stage of ladle pouring, resulting in the phenomenon of slag entrainment, while the existing technology forces the closing of the nozzle when the slag entrainment occurs, resulting in the existence of residual molten steel in the ladle, resulting in wasted waste. Problem, the present invention provides a device for limiting the vortex generation of ladle, the present invention hinders the energy of vortex formation and development from the aspect of fluid dynamics, changes the flow mode of molten steel near the water outlet, and achieves the purpose of effectively suppressing vortex formation.

2. Technical solutions

In order to achieve the above object, the technical scheme provided by the invention is:

The invention relates to a device for limiting the generation of ladle vortex. The vortex blocking device is an elliptical hemispherical device, and a plurality of openings are opened along the circumferential direction of the device. The molten steel enters the steel outlet at the bottom of the metallurgical device through the openings; The whirling device is arranged above the steel outlet and is fixedly connected with the bottom of the ladle.

Further, the material of the vortex blocking device is a refractory material, the number of openings of the vortex blocking device is an even number, and the vortex blocking device is symmetrically distributed along the circumferential direction of the vortex blocking device.

Further, the inner width of the swirl blocking device is larger than the diameter of the steel tap, and the diameter of the side opening of the vortex blocking device is greater than or equal to the diameter of the tap hole.

Further, the inner circle radius R ₀ of the swirl resistance device is calculated by formula (2):

Among them, R ₀ is the radius of the inner circle of the swirl resistance device, l ₀ is the clear span length of the inner circle, and f ₀ is the sagittal height of the inner circle.

Further, the radius R of the axis circle of the swirl resistance device is calculated according to formula (5):

Among them, m ₀ is the center distance between the axis circle and the inner circle, and d ₀ is the thickness of the vault concrete; the center distance m ₀ between the axis circle and the inner circle is calculated according to formula (4):

In the formula, Δ is the difference between the thickness d _j of the arch foot and the thickness d ₀ of the vault concrete,

Δ=d _j −d ₀ (3).

Further, the outer circle geometric dimensions of the vortex resistance device are calculated according to formulas (9), (10) and (11) respectively;

Outer circle span:

l ₁ =l ₀ +2d _h (9)

Outer circle sagittal height:

f ₁ =f ₀ +d ₀ -d _v (10)

Outer circle radius:

Among them, l ₁ is the clear span width of the outer circle arc; l ₀ is the clear span width of the inner circle; d _h is the auxiliary parameter 1 of the axis arc; f ₀ is the sagittal height of the inner circle; f ₁ is the sagittal height of the outer circle; d _v is the axis circle Arc auxiliary parameter 2; d ₀ is the thickness of the vault concrete; R ₁ is the radius of the outer circle; d _h and d _v are calculated according to formulas (6), (7) and (8);

为轴线圆弧辅助角。in the formula

Auxiliary angle for the axis arc.

Further, the relationship between the inner circle clear span length l ₀ of the swirl resistance device and the diameter D of the tap hole is specifically designed as D≤l ₀ ≤1.5D; the concrete thickness d ₀ of the vault and the thickness of the arch foot The specific control range of d _j is 0.25D≤d ₀ ≤2D, 0.25D≤d _j ≤2D; the specific control range of the inner sagittal height f ₀ and the inner height h ₀ of the vortex blocking device is 0.25D≤f ₀ ≤0.75 D; _{0≤h0≤0.5D} .

In the present invention, the swirl blocking device is connected with the bottom of the ladle, and the molten steel enters the steel outlet at the bottom of the ladle through the swirling blocking device, so as to achieve the purpose of reducing the swirling and penetration height of the molten steel vortex.

3. Beneficial effects

Adopting the technical scheme provided by the present invention, compared with the existing known technology, has the following remarkable effects:

(1) In view of the fact that during the steelmaking process, vortices will be generated in the metallurgical device at the end of the ladle pouring, resulting in the phenomenon of slag entrainment, and the existing technology forces the closing of the nozzle when the slag entrainment occurs, resulting in the waste of remaining molten steel in the ladle. The problem is that a device for limiting the vortex generation of the ladle of the present invention is to set a vortex blocking device at the steel outlet of the metallurgical device to establish an area that hinders the formation of the flow field, and hinder the energy from the formation and development of the vortex from the aspect of fluid dynamics, and Change the movement direction of the fluid near the outlet, greatly reduce the height of molten steel produced by the vortex, delay the time of whirlpool, reduce the height of whirl and penetration by 90-100%, increase the yield of molten steel, prevent slag, and improve tapping quality and lower production costs.

(2) The number of openings around the vortex blocking device of the present invention is an even number, and the flow field formed near the ladle outlet is dispersed into mirror symmetry, so that the flow fields on both sides of the fluid interact and restrict each other, thereby suppressing the generation of vortices; vortex blocking; The device is designed as an elliptical hemisphere, which conforms to the design of structural mechanics, so that the vortex blocking device can withstand the pressure of molten steel.

(3) The vortex blocking device of the present invention is assembled at the bottom of the ladle and can better withstand the pressure of the molten steel; and the structure of the whirl blocking device is specifically designed according to structural mechanics, so as to ensure the structural strength of the whirl blocking device while reducing the material At the same time, the vortex blocking device of the present invention adopts refractory material, which can ensure that the vortex blocking device does not change in properties under high temperature, so that the whirl blocking device can work for a long time.

Description of drawings

Fig. 1 is the schematic diagram of the direction of the nozzle vortex when the ladle reactor is in the northern hemisphere;

Fig. 2 is the schematic diagram of the direction of the nozzle vortex when the ladle reactor is in the southern hemisphere;

3 is a schematic structural diagram of the vortex blocking device of the present invention;

4 is a cross-sectional view of the swirl resistance device of the present invention;

5 is a schematic diagram of tapping in the metallurgical reactor;

FIG. 6 is a schematic diagram of the installation of the swirl resistance device of the present invention in a metallurgical reactor.

Detailed ways

In order to further understand the content of the present invention, the present invention will be described in detail with reference to the accompanying drawings and embodiments.

According to the principle of Coriolis force and fluid mechanics, the invention places a swirl blocking device made of refractory material above the nozzle where the ladle has tapping phenomenon to limit the formation of the vortex flow field, thereby inhibiting the generation of vortex. The inner width of the swirl blocking device is larger than the diameter of the steel tapping hole, and the swirling blocking device is above the steel tapping hole. The bottom end of the swirling blocking device is connected with the bottom of the ladle to form an integral body, and the molten steel enters the tapping hole at the bottom of the metallurgical device through the swirling blocking device.

A specific introduction is made below in conjunction with the embodiment:

Example 1

Referring to FIG. 3 , the vortex blocking device of this embodiment is an elliptical hemispherical device, and an even number of openings are provided along the circumferential direction of the device, and the openings are symmetrically distributed along the circumferential direction of the vortex blocking device. In this embodiment, the number of openings of the vortex blocking device is four. The even-numbered openings of the symmetric subdivision disperse the flow field formed near the ladle outlet into mirror symmetry, so that the flow fields on both sides of the fluid interact and restrict each other, thereby suppressing the generation of vortices. The elliptical hemispherical swirl blocking device conforms to the structural mechanics design, so that the vortex blocking device can withstand the pressure of molten steel. The molten steel enters the tapping hole at the bottom of the metallurgical device through the opening. The swirl blocking device is arranged above the tapping port and is fixedly connected with the bottom of the ladle, so that it can better withstand the pressure of the molten steel. The inner width of the swirl blocking device is larger than the diameter of the steel tapping port, and the diameter of the side opening is larger than or equal to the diameter of the steel tapping port.

It is worth mentioning that the size of the vortex blocking device is specifically limited in this embodiment, and the structure of the vortex blocking device is specifically designed according to structural mechanics. While ensuring the structural strength of the vortex blocking device, it reduces the use of materials and saves money. cost. At the same time, refractory materials are used to make the vortex blocking device work stably for a long time under high temperature conditions.

Referring to Figure 4, the ladle tap diameter is D, the inner circle clear span is l ₀ , the inner circle sagittal height is f ₀ , the vault concrete thickness is d ₀ , the arch foot thickness is d _j , and h ₀ is the inner height of the vortex blocking device . The inner circle clear span length _l0 is greater than the diameter of the steel tapping hole, and spans above the steel tapping hole, otherwise it will hinder the tapping of the molten steel from the ladle, resulting in serious erosion of the refractory material during the tapping process of the ladle. Generally, the length of the clear span can be appropriately increased according to the requirement of the tapping amount, and in this embodiment, D≤l ₀ ≤1.5D. According to the definition of the compressive strength and tensile strength of the refractory material, the concrete thickness d ₀ of the vault and the thickness d _j of the arch foot are controlled within the safety factor range. In this embodiment, the specific control range is _{0.25D≤d0≤2D} , 0.25 _D≤dj≤2D . The inner sag height f ₀ and the inner height h ₀ of the swirl blocking device are scale factors for adjusting the size of the tapping amount, in this embodiment, 0.25D≤f ₀ ≤0.75D, 0≤h ₀ ≤0.5D.

The above-mentioned inner circle clear span length l ₀ , inner circle sag height f ₀ and inner height h ₀ of the swirl blocking device are all factors for adjusting the tapping amount. Among them, the height h ₀ in the swirl blocking device is the dominant factor in controlling the tapping volume, which can be appropriately changed according to the longitude and latitude of the location of the earth and the tapping volume per unit time of the ladle of the corresponding steel mill. For example, the closer to the equator, the greater the influence of the Coriolis force, and the height h ₀ in the vortex resistance device can be appropriately reduced.

The specific parameter calculation formula of the vortex resistance device of the present embodiment is as follows:

The inner circle radius R ₀ is calculated according to formula (2):

Among them, R ₀ is the radius of the inner circle of the swirl resistance device, l ₀ is the clear span length of the inner circle, and f ₀ is the sagittal height of the inner circle.

Δ is the difference between the arch foot thickness d _j and the vault concrete thickness d ₀ ,

Δ=d _j -d ₀ (3)

The deriving of the outer circle radius R needs to be assisted by the concept of leading out the axis circle. The center distance m ₀ between the axis circle and the inner circle is:

The radius R of the axis circle of the swirl resistance device is calculated according to formula (5):

At the same time, d _h (axis arc auxiliary parameter 1) and d _v (axis arc auxiliary parameter 2) are calculated according to formulas (6), (7), (8):

为轴线圆弧辅助角。in the formula

Auxiliary angle for the axis arc.

The geometric dimensions of the outer circle of the swirl resistance device in this embodiment are calculated according to formulas (9), (10) and (11) respectively;

Outer circle span:

l ₁ =l ₀ +2d _h (9)

Outer circle sagittal height:

f ₁ =f ₀ +d ₀ -d _v (10)

Outer circle radius:

Among them, l ₁ is the clear span width of the outer circle arc; l ₀ is the clear span width of the inner circle; d _h is the auxiliary parameter 1 of the axis arc; f ₀ is the sagittal height of the inner circle; f ₁ is the sagittal height of the outer circle; d _v is the axis circle Arc auxiliary parameter 2; d ₀ is the thickness of the vault concrete; R ₁ is the radius of the outer circle.

Due to the centrifugal force generated by the earth's rotation, the magnitude and direction of the Coriolis force are different according to different geographical locations, and the strength and direction of the vortex generated by the fluid are also different, which is shown as a counterclockwise direction in the northern hemisphere and a clockwise direction in the southern hemisphere (see Fig. 1 and Figure 2), the Coriolis force is greater the closer the region is to the equator. According to different geographical locations, the intensity of the Coriolis force is different, and the size of the vortex blocking device in this embodiment can be adjusted as required. When installed in the northern hemisphere, Figure 5 shows the rotation direction of molten steel in the metallurgical reactor, and the swirl blocking device is built above the nozzle as shown in Figure 6, and is fixedly connected to the bottom of the ladle. The flow trend of the fluid near the nozzle is a counterclockwise trend. The existence of the swirl blocking device will hinder the flow of the fluid, completely inhibit the formation of vortices, and reduce the height of swirl and penetration by 90%-100%. Installations are reduced by more than 40%.

Example 2

In the swirl resistance device of this embodiment, a 1:1 physical model is established in the laboratory physical simulation experiment, and the swirl resistance device is installed at the bottom of the ladle. The swirl resistance device is realized by 3D printing. The critical height of the vortex in the final stage is controlled, so as to achieve the purpose of reducing the height of the molten steel vortex swirl and penetration. The specific steps are:

(1) Design of specific parameters of the vortex resistance device: the diameter D of the nozzle is 70mm, of which the inner circle clear span _l0 is 70mm; the inner circle sagittal height _f0 is 35mm; the dome concrete thickness _d0 is 30mm, and the arch foot thickness _dj is 60mm . The inner circle radius R ₀ is 35mm, the difference between the thickness of the arch foot section and the vault section thickness is 30mm; the outer circle clear span is _173.3846mm ; the outer circle sagittal height is 34.5385mm; Above the ladle tap.

(2) Use water instead of molten steel, add water to the specified level of molten steel, open the nozzle after standing for 4 minutes, use a high-speed camera to record the swirling and penetration height of the ladle, and repeat the experiment several times.

(3) The experimental results are good, the swirl height is 90% lower than that of the unobstructed swirl device, and the penetration height is 95% lower.

Example 3

The swirl blocking device of this embodiment is tested by installing a vortex blocking device at the bottom of the ladle of Shanghai Meishan Iron and Steel No. 2 steelmaking to control the critical height of the vortex at the end of the ladle tapping, so as to reduce the vortex swirl and penetration height of the molten steel. The specific steps are as follows: :

(1) Design of specific parameters of the vortex resistance device: the diameter D of the nozzle is 70mm, of which the inner circle clear span _l0 is 70mm; the inner circle sagittal height _f0 is 35mm; the dome concrete thickness _d0 is 30mm, and the arch foot thickness _dj is 60mm . The inner circle radius R ₀ is 35mm, the difference between the thickness of the arch foot section and the vault section is 30mm; the outer circle clear span is 173.3846mm; the outer circle sagittal height is 34.5385mm; the outer circle radius R1 is 125.0690mm.

(2) The test results reflect that the remaining steel in the ladle is significantly reduced. In April 2019, the average amount of excess steel poured in the ladle of the steelmaking plant in 2018 decreased by 735.02 tons, which was converted into an average reduction of 1.6 tons of excess steel per heat of the test ladle. Compared with the average steel remaining in the ladle of 3.36 tons/heat in 2018, the remaining steel in the test heat is reduced by 47.6%, and the benefits are significant.

The present invention and its embodiments have been described above schematically, and the description is not restrictive, and what is shown in the accompanying drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it, without departing from the purpose of the present invention, any structural modes and embodiments similar to this technical solution are designed without creativity, which shall belong to the protection scope of the present invention. .

Claims (8)

1. A device for limiting ladle vortex generation, characterized in that: the vortex resistance device is an elliptical hemispherical device, and a plurality of openings are opened along the circumferential direction of the device, and molten steel enters the metallurgical bottom tapping port through the opening; The swirl blocking device is arranged above the tapping port and is fixedly connected with the bottom of the ladle. 2. A device for limiting the generation of ladle vortex according to claim 1, characterized in that: the material of the vortex blocking device is refractory material, the number of openings of the vortex blocking device is an even number, and the vortex blocking device is symmetrical along the circumferential direction of the vortex blocking device. distributed. 3. A device for restricting ladle vortex generation according to claim 1 or 2, wherein the inner width of the vortex blocking device is larger than the diameter of the tap hole, and the diameter of the side opening of the vortex blocking device is greater than or Equal to the diameter of the tap hole. 4. A device for limiting the generation of ladle vortex according to claim 3, characterized in that: the inner circle radius R ₀ of the vortex blocking device is calculated by formula (2):

Among them, R ₀ is the radius of the inner circle of the swirl resistance device, l ₀ is the clear span length of the inner circle, and f ₀ is the sagittal height of the inner circle. 5. A device for limiting the generation of ladle vortex according to claim 4, characterized in that: the radius R of the axis circle of the vortex blocking device is calculated according to formula (5):

Among them, m ₀ is the center distance between the axis circle and the inner circle, and d ₀ is the thickness of the vault concrete; the center distance m ₀ between the axis circle and the inner circle is calculated according to formula (4):

In the formula, Δ is the difference between the thickness d _j of the arch foot and the thickness d ₀ of the vault concrete, Δ=d _j −d ₀ (3). 6. The device for limiting the generation of ladle vortices according to claim 5, wherein the geometrical dimensions of the outer circle of the vortex blocking device are calculated according to formulas (9), (10) and (11) respectively. ; Outer circle span: l ₁ =l ₀ +2d _h (9) Outer circle sagittal height: f ₁ =f ₀ +d ₀ -d _v (10) Outer circle radius:

Among them, l ₁ is the clear span width of the outer circle arc; l ₀ is the clear span width of the inner circle; d _h is the auxiliary parameter 1 of the axis arc; f ₀ is the sagittal height of the inner circle; f ₁ is the sagittal height of the outer circle; d _v is the axis circle Arc auxiliary parameter 2; d ₀ is the thickness of the vault concrete; R ₁ is the radius of the outer circle; d _h and d _v are calculated according to formulas (6), (7) and (8);

in the formula

Auxiliary angle for the axis arc. 7. A device for limiting the generation of ladle vortex according to claim 6, characterized in that: the relationship between the inner circle clear span length ₁₀ of the vortex blocking device and the diameter D of the tap hole is specifically designed as D ≤l ₀ ≤1.5D; the specific control range of the concrete thickness d ₀ of the vault and the thickness d _j of the arch foot is 0.25D≤d ₀ ≤2D, 0.25D≤d _j ≤2D; the inner sagittal height f ₀ The specific control range of the height h ₀ in the vortex blocking device is 0.25D≤f ₀ ≤0.75D; 0≤h ₀ ≤0.5D. 8. An application for limiting ladle vortex generating device, characterized in that: the vortex blocking device according to any one of claims 1-7 is connected to the bottom of the ladle, and molten steel enters the ladle through the vortex blocking device Bottom tapping port, to achieve the purpose of reducing the swirling and penetration height of molten steel swirl.

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