Spherical sealing pressure balance type steel ladle long nozzle

Abstract

The invention discloses a spherical sealing pressure balance type steel ladle long nozzle which comprises a steel ladle collector nozzle and a steel ladle long nozzle body, the steel ladle collector nozzle, the steel ladle long nozzle body and a sealing gasket are sealed through pressing, and a plurality of argon balance channels are formed in a lower body of a spherical sealing section of the steel ladle long nozzle body. And the argon balancing channel is communicated with the external argon sealing cavity and the inner cavity of the water gap, so that the negative pressure of the inner cavity caused by molten steel circulation is balanced during use. The matched sealing mode of the steel ladle long nozzle and the steel ladle collector nozzle is improved, the tolerance of installation centering degree is improved, the sealing effect is improved, and the operation complexity is reduced; and meanwhile, the internal pressure of the long nozzle is balanced, and the risk of external air entrainment caused by internal negative pressure of the long nozzle is reduced.

Description

Technical Field

[0001] The invention relates to the field of metallurgical continuous casting, in particular to a spherical sealing pressure-balanced ladle shroud. Background Art

[0002] The ladle shroud is the key refractory channel connecting the molten steel between the ladle and the tundish. It mainly prevents the molten steel from contacting with the air during the casting process, which leads to the increase of oxygen and nitrogen content in the steel and the decrease of acid-soluble aluminum content, which affects the purity of the molten steel. The outlet of the lower part of the shroud is inserted into the molten steel in the tundish, and the upper part is closely matched with the ladle shroud to form a seal. In order to ensure the sealing effect, the ladle shroud and the large ladle sleeve currently used generally adopt conical surface sealing, and the taper is small (~20°), which has high requirements for assembly centering. If there is a slight tilt, the surface seal will become a line seal, and the sealing performance is poor (CN104607627A, CN204818038U). At the same time, due to the large flow rate of the steel flow inside the shroud, the negative pressure in the pipe is large. During use, it is inevitable that air will be inhaled from the gap between the ladle shroud, the shroud and the sealing gasket, resulting in secondary oxidation. In view of this phenomenon, the common practice is to fill the ladle shroud and the shroud interface with protective argon gas to avoid air inhalation as much as possible. Among them, the more ideal is the hood method, that is, a box or hood filled with argon is used to seal the ladle outlet and the long nozzle interface at the bottom of the ladle. This method is more complicated to install, and casting abnormalities are difficult to handle (CN215615054U). The current mainstream method is to arrange a circle of annular argon devices at the ladle outlet and the long nozzle interface, and blow argon into it to form a circle of argon gas curtain protection, but this open environment is easily affected by the on-site working conditions, resulting in an incomplete argon gas curtain, and when the sealing conditions are poor, the convection generated by the external argon flow and the air will also increase the risk of air entrainment leading to secondary oxidation of molten steel (CN207372277U). To address this problem, some technicians have proposed setting up a layer of argon channels in the nozzle and passing the argon channels into the inner cavity of the nozzle through the inner wall holes to provide argon protection. However, the structure is complex, the processing is difficult, the safety risk is high, and the argon flow rate is difficult to control. It is easy for argon to enter the tundish along with the steel flow, causing the liquid level in the tundish to fluctuate and slag to roll (CN215657825U).

[0003] Therefore, it is necessary to develop a new type of ladle long nozzle structure to overcome the above problems. Summary of the invention

[0004] Purpose of the invention: In view of the shortcomings and defects of the prior art, the present invention provides a spherical sealing pressure-balanced ladle shroud, which improves the sealing method of the ladle shroud and the ladle lower water outlet, increases the tolerance to installation centering, improves the sealing effect and reduces the operation complexity; at the same time, it balances the internal pressure of the shroud and reduces the risk of external air entrainment due to the negative pressure inside the shroud.

[0005] Technical solution: A spherical sealing pressure-balanced ladle shroud of the present invention is characterized in that it includes a ladle lower shroud and a ladle shroud, the ladle lower shroud, the ladle shroud and the sealing gasket are sealed by compression, and a plurality of argon balancing channels are provided on the lower body of the spherical sealing section of the ladle shroud, the argon balancing channels connect the external argon sealing cavity and the internal cavity of the shroud, and balance the negative pressure of the inner cavity caused by the circulation of molten steel when in use.

[0006] Wherein, a spherical sealing section is arranged between the lower conical section and the middle straight section of the ladle outlet, and a spherical sealing section is arranged on the inner wall of the ladle long outlet.

[0007] The spherical surface size of the spherical sealing section of the ladle water outlet and the ladle water outlet is consistent. When used in combination, the ladle water outlet and the ladle water outlet are tightly sealed through the spherical surface.

[0008] Wherein, the width of the spherical sealing surface of the spherical sealing section of the ladle lower water inlet and the ladle long water inlet is 10mm-40mm, and the curvature is 10°-30°.

[0009] Wherein, the sealing gasket is made of an integrally formed refractory sealing material, and its shape and size are consistent with the shape of the inner wall of the upper interface of the ladle long nozzle.

[0010] Wherein, the diameter of the argon balance channel is 1mm-5mm, and the number is 2-10.

[0011] Wherein, the balance argon pressure of the argon balance channel is 0.1MPa-0.5MPa, and the flow rate is 50NL / min-200NL / min.

[0012] Wherein, an argon gas interface is provided on the side of the long water inlet of the ladle.

[0013] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: the present invention improves the sealing method of the ladle shroud and the ladle lower water inlet, improves the tolerance to installation centering, improves the sealing effect and reduces the operation complexity; at the same time, it balances the internal pressure of the shroud and reduces the risk of external air entrainment due to the negative pressure inside the shroud.

[0014] Compared with traditional conical sealing effects, the present invention has a better sealing effect, has lower requirements on the centering during the operation process, and can tolerate a certain degree of tilt. At the same time, the pressure balance of the external argon sealing cavity and the internal cavity of the water nozzle is achieved through the argon balance channel, avoiding the back suction of air due to the negative pressure in the inner cavity, and effectively reducing the secondary oxidation of molten steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a conical seal in the prior art;

[0016] Figure 2 It is a schematic diagram of the structure of the spherical seal of the present invention;

[0017] Figure 3 Schematic diagram of the deflection structure of the conical seal in the prior art; in the figure, a is the deflection angle; b is the remaining sealing surface width; c is the deflection gap;

[0018] Figure 4 Schematic diagram of the deflection structure of the spherical seal of the present invention; in the figure, a is the deflection angle; b is the remaining sealing surface width; c is the deflection gap;

[0019] In the figure, 1 is the ladle outlet; 2 is the ladle long outlet; 3 is the sealing gasket; 4 is the argon gas interface; and 5 is the argon gas balance channel. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0021] The spherical sealing pressure-balanced ladle shroud of the present invention comprises a ladle lower shroud 1 and a ladle shroud 2. The ladle lower shroud 1, the ladle shroud 2 and the sealing gasket 3 are sealed by compression. The lower body of the spherical sealing section of the ladle shroud 2 is provided with a plurality of argon balancing channels 5. The argon balancing channels 5 connect the external argon sealing cavity with the internal cavity of the shroud to balance the negative pressure of the inner cavity caused by the circulation of molten steel when in use.

[0022] Among them, a spherical sealing section is provided between the lower conical section and the middle straight section of the ladle water outlet 1, and a spherical sealing section is provided on the inner wall of the ladle long water outlet 2. The spherical dimensions of the spherical sealing sections of the ladle water outlet 1 and the ladle long water outlet 2 are consistent, and when used in combination, the ladle water outlet 1 and the ladle long water outlet 2 are tightly sealed through the spherical surface. The width of the spherical sealing surface of the spherical sealing section of the ladle water outlet 1 and the ladle long water outlet 2 is 10mm-40mm, and the curvature is 10°-30°. The sealing gasket 3 is made of an integrally molded refractory sealing material, and its shape and size are consistent with the shape of the inner wall of the upper interface of the ladle long water outlet 2. The diameter of the argon balance channel 5 is 1mm-5mm, and the number is 2-10. The balanced argon pressure of the argon balance channel 5 is 0.1MPa-0.5MPa, and the flow rate is 50NL / min-200NL / min. An argon interface 4 is provided on the side of the ladle long water outlet 2.

[0023] Al deoxidized steel was selected as the casting object for the test. The total oxygen content in the ladle was controlled at about 5ppm and the N content was controlled at about 30ppm. Ten furnaces were continuously cast, and the oxygen and N contents of the molten steel in the first, middle and last three furnaces were tested. The average value was taken as the evaluation method for the effect of protective casting.

[0024] Comparative Example 1:

[0025] For the comparative casting, the existing conical sealing long water inlet and the matching ladle down-water inlet were used, the width of the conical sealing surface was 40mm, the argon pressure was 0.5MPa, and the flow rate was 200NL / min; the average total oxygen content in the tested tundish was 12ppm, and the average N content was 49ppm.

[0026] Embodiment 1:

[0027] This embodiment adopts the spherical sealing long water inlet and the matching ladle downspout of the present invention, the width of the spherical sealing surface is 40mm; the diameter of the argon balance channel is 1mm, and the number is 10; the argon pressure is 0.1MPa, and the flow rate is 200NL / min; the average total oxygen content of the tested tundish is 5.5ppm, and the average N content is 32ppm.

[0028] Embodiment 2:

[0029] This embodiment adopts the spherical sealing long water inlet and the matching ladle downspout of the present invention, the width of the spherical sealing surface is 10mm; the diameter of the argon balance channel is 2mm, and the number is 5; the argon pressure is 0.25MPa, and the flow rate is 200NL / min; the average total oxygen content of the tested tundish is 8.9ppm, and the average N content is 41ppm.

[0030] Embodiment 3:

[0031] This embodiment adopts the spherical sealing long water inlet and the matching ladle downspout of the present invention, the width of the spherical sealing surface is 20mm; the diameter of the argon balance channel is 2mm, and the number is 5; the argon pressure is 0.5MPa, and the flow rate is 50NL / min; the average total oxygen content of the tested tundish is 6.7ppm, and the average N content is 36ppm.

[0032] Embodiment 4:

[0033] This embodiment adopts the spherical sealing long water inlet and the matching ladle downspout of the present invention, the width of the spherical sealing surface is 30mm; the diameter of the argon balance channel is 5mm, and the number is 2; the argon pressure is 0.2MPa, and the flow rate is 100NL / min; the average total oxygen content of the tested tundish is 7.5ppm, and the average N content is 39ppm.

[0034] Table 1: Comparison table of comparative example 1 and embodiments 1-4

[0035]

[0036] like Figure 3 and Figure 4, at the same deflection angle (~10°), a larger deflection gap is formed on one side of the conical seal (c), and the width of the remaining sealing surface is also smaller (b); while the deflection angle of the spherical sealing surface is smaller (e), and the width of the remaining sealing surface is also wider (d).

[0037] Compared with traditional conical sealing effects, the present invention has a better sealing effect, has lower requirements on the centering during the operation process, and can tolerate a certain degree of tilt. At the same time, the pressure balance of the external argon sealing cavity and the internal cavity of the water nozzle is achieved through the argon balance channel, avoiding the back suction of air due to the negative pressure in the inner cavity, and effectively reducing the secondary oxidation of molten steel.

[0038] After the technology of the present invention is put into use, the secondary oxidation of molten steel in the continuous casting process can be improved, the quality of steel can be improved, the loss rate can be reduced by 1%, the labor intensity of workers and the consumption of ton of steel and refractory materials can be reduced. Calculated based on a steel production capacity of 10 million tons, it is expected to reduce costs and increase profits by more than 20 million yuan per year.

Claims

1. A spherical sealing pressure balanced ladle shroud, characterized in that: The invention comprises a ladle water outlet (1) and a ladle long water outlet (2). The ladle water outlet (1), the ladle long water outlet (2) and a sealing gasket (3) are sealed by pressing. The lower body of the spherical sealing section of the ladle long water outlet (2) is provided with a plurality of argon balance channels (5). The argon balance channels (5) are connected with an external argon sealing cavity and an internal cavity of the water outlet to balance the negative pressure of the internal cavity caused by the circulation of molten steel when in use.

2. The spherical sealing pressure-balanced ladle shroud according to claim 1, characterized in that: The ladle outlet (1) is provided with a spherical sealing section between the lower conical section and the middle straight section, and the inner wall of the ladle long outlet (2) is provided with a spherical sealing section.

3. The spherical sealing pressure-balanced ladle shroud according to claim 2, characterized in that: The spherical surface sizes of the spherical sealing sections of the ladle water outlet (1) and the ladle water outlet (2) are consistent. When used in combination, the ladle water outlet (1) and the ladle water outlet (2) are tightly sealed through the spherical surface.

4. The spherical sealing pressure-balanced ladle shroud according to claim 3, characterized in that: The spherical sealing surfaces of the spherical sealing sections of the ladle lower water inlet (1) and the ladle long water inlet (2) have a width of 10 mm to 40 mm and an arc of 10° to 30°.

5. The spherical sealing pressure-balanced ladle shroud according to claim 1, characterized in that: The sealing gasket (3) is made of an integrally formed refractory sealing material, and its shape and size are consistent with the shape of the inner wall of the upper interface of the ladle shroud (2).

6. The spherical sealing pressure-balanced ladle shroud according to claim 1, characterized in that: The diameter of the argon balance channel (5) is 1 mm-5 mm, and the number is 2-10.

7. The spherical sealing pressure-balanced ladle shroud according to claim 6, characterized in that: The balance argon pressure of the argon balance channel (5) is 0.1MPa-0.5MPa, and the flow rate is 50NL / min-200NL / min.

8. The spherical seal pressure balance ladle shroud according to claim 1, characterized in that: An argon gas interface (4) is provided on the side of the ladle long shroud (2).

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