CN115246004A - Tundish capable of preventing covering agent from being involved and using method thereof - Google Patents

Abstract

The present invention relates to a tundish for preventing the involvement of a covering agent and a method of using the same. The tundish includes a tundish body (1), a long nozzle (2), a submerged nozzle (3), a tundish cover (4) and a weir plate (5); the tundish cover is arranged on the opening of the tundish body, A sealing fiber is arranged at the connection between the tundish cover and the opening; the weir plate is fixedly arranged inside the tundish body along the vertical direction, and the interior of the tundish body is divided into a mixing area and a pouring area, and a through-steel hole (51) is arranged on the weir plate ; The tundish cover above the mixing area is provided with a long nozzle hole and an auxiliary hole adjacent to it, and a long nozzle is arranged in the long nozzle hole; an argon gas pipeline (6) is arranged in the tundish cover above the pouring area, and the tundish body is in the lower part of the pouring area. Set up immersion nozzles. The invention can prevent the secondary oxidation of molten steel without using a covering agent in the pouring area, and at the same time avoid the problem that the covering agent is involved in low-tonnage pouring.

Description

Tundish for preventing covering agent from getting involved and method of using the same

technical field

The invention relates to a tundish technology, in particular to a tundish for preventing the involvement of a covering agent and a method for using the same.

Background technique

The continuous casting process includes equipment such as ladle, tundish and mold. The tundish is a refractory container, which usually includes a tundish body, a long nozzle and a submerged nozzle. The nozzle enters the tundish and then enters the crystallizer from the submerged nozzle.

The tundish mainly has the following metallurgical functions:

1. Diversion effect: For multi-strand continuous casting machines, the molten steel is diverted by the multi-nozzle tundish;

2. Continuous pouring effect: when multiple furnaces are continuously poured, the molten steel stored in the tundish plays a connecting role in the process of changing the package;

3. Decompression effect: provide a stable molten steel level during continuous casting to reduce the erosion of molten steel flow to the solidified shell of the mold;

4. Prevent secondary oxidation: add a covering agent to the molten steel surface in the tundish or adopt technical measures such as blowing argon to reduce the pollution of the molten steel in the tundish by external oxygen sources;

5. Removal of inclusions: The molten steel stays in the tundish for a sufficient time to float and remove the particles of non-metallic inclusions in the molten steel.

During the pouring process of molten steel, especially in the case of low tonnage pouring, if the molten steel level in the tundish drops to the critical level, a vortex will form above the submerged nozzle, so that the covering agent on the molten steel surface of the tundish runs along the center of the vortex. It is involved in the submerged nozzle, thus affecting the quality of the billet, resulting in a decrease in the yield of the billet and an increase in production costs. At present, the technologies used to inhibit the tundish covering agent from being involved or the vortex slag are mainly as follows:

1. Control the pouring height of the ladle. For example, Chinese Patent No. 201510594862.6 discloses a method for preventing slag in the tundish. The height difference between the bottom of the molten steel tank and the liquid level of the tundish can be reduced to the maximum extent, so as to reduce the agitation of the molten pool of the tundish caused by the molten steel flow, and prevent the occurrence of slag in the tundish.

2. Optimize the structure of the stopper. For example, Chinese Patent No. 201810294020.2 discloses a continuous casting anti-slag stopper. The stopper uses the unique shape of the anti-slag functional section to weaken or even offset the generation and reduction of the tundish molten steel confluence vortex. The purpose of continuous casting slag risk.

3. Add a swirl suppression device at the molten steel outlet of the tundish. For example, Chinese Patent No. 201120535201.3 discloses an anti-rolling slag cap for the tundish pouring mouth. There is a fixed rod on the top of the helmet, and at least two steel inlet holes are opened obliquely along the middle of the circumference of the helmet to effectively suppress the formation of eddy currents in the tundish at the end of the pouring stage, thereby preventing the slag from rolling; another example is disclosed in Chinese Patent 201220546085.X A device for reducing the liquid level of the tundish slag in the bloom. The device is mainly composed of a swirl suppressor. The swirl suppressor is composed of a cylinder and a platform at the top, which is in the shape of a right angle. The bottom of the cylinder is fixed at each On the permanent layer of the bottom of the tundish around the water outlet of the tundish, the platform is located directly above the water outlet to prevent the tundish from causing slag during the pouring process, thereby improving the purity and yield of molten steel.

The principles of these technologies are all realized by suppressing the generation of vortices, but there is still the problem of vortex generation. Therefore, these technologies can only reduce the amount of slag entrained to a certain extent, but cannot completely avoid the problem of tundish entrainment under low tonnage conditions.

In addition, the argon blowing technology currently used in the tundish cannot completely isolate air. For example, Chinese Patent No. 201520435558.2 discloses an argon blowing sealed tundish. The branch pipe is connected to the argon blowing pipe through the working layer, so that the argon blowing branch pipe is located on the molten steel surface, so as to realize the argon atmosphere and isolate the air on the molten steel surface. Although the tundish can isolate the air to a certain extent, it needs to be The flow rate of argon blowing is relatively large, and it is impossible for argon to completely cover the molten steel surface in actual use, and secondary oxidation cannot be completely avoided.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a tundish for preventing the covering agent from being involved and a method of using the same. The tundish can seal the pouring area of the tundish by setting a tundish cover at the opening and combining the weir structure in the tundish. The structure prevents the secondary oxidation of molten steel without using a covering agent in the pouring area, and at the same time avoids the problem of the covering agent being involved in low-tonnage pouring.

The present invention is realized in this way:

A tundish for preventing covering agent from being involved, comprising a tundish body, a long nozzle and a submerged nozzle; the tundish further comprises a tundish cover and a weir plate;

The tundish cover is arranged on the opening of the tundish body, and the connection between the tundish cover and the opening is provided with sealing fibers; the weir plate is fixedly arranged inside the tundish body along the vertical direction, and divides the interior of the tundish body into two parts. In the mixing area and the pouring area, steel holes are arranged on the weir plate; the tundish above the mixing area is covered with adjacent long nozzle holes and auxiliary holes, and a long nozzle is arranged in the long nozzle holes; the tundish above the pouring area An argon gas pipeline is arranged in the cover, and an immersion nozzle is arranged in the lower part of the pouring area of the tundish body.

The weir plate is arranged at 1/2~1/4 of the length direction of the tundish body and is close to the submerged nozzle.

The distance between the through steel hole and the inner bottom surface of the tundish body is 0-300mm.

The through-steel hole is set with an upward inclination angle from the mixing zone to the pouring zone.

The inclination angle is 0-80°.

The tundish further includes a turbulence controller and is arranged at the lower part of the mixing zone at a position corresponding to the long nozzle.

A method for using a tundish for preventing the involvement of a covering agent, using the tundish, the method comprising the steps of: first purging the pouring area with argon gas, then pouring molten steel, and the molten steel enters the mixing area from a long nozzle; After the molten steel level is higher than the through-steel hole, a covering agent is added to the molten steel surface near the long nozzle through the auxiliary hole; the molten steel enters the pouring area from the mixing area through the through-steel hole, and then drains out of the tundish through the submerged nozzle.

The molten steel level needs to be 50-100mm higher than the through-steel hole before adding a covering agent.

The tundish of the present invention prevents the covering agent from being involved. First, a tundish cover and sealing fibers are arranged at the opening of the tundish body, and a weir plate is arranged in the tundish body to obtain a mixing zone and a pouring zone. A fully sealed space can be achieved. No covering agent needs to be added after the molten steel enters the pouring area. It only needs a small amount of argon purging in advance or no argon blowing to prevent the secondary oxidation of the molten steel. It can effectively prevent the covering agent from being involved in the submerged nozzle during low tonnage casting, so that the quality of the billet will not be affected. Secondly, the turbulence controller and the weir plate are arranged in the tundish body, which can effectively control the flow field of molten steel in the tundish and help the inclusions in the molten steel to float up and remove.

The method of using the tundish for preventing the covering agent from being involved in the present invention can avoid using the covering agent in the pouring area based on the fully sealed space that the tundish can achieve in the pouring area, and the molten steel level in the mixing area is higher than the steel hole When adding a covering agent to the mixing area, it can not only avoid the problem of secondary oxidation of molten steel in the mixing area, but also ensure that the covering agent on the molten steel surface in the mixing area will not enter the pouring area, especially in the low-tonnage unsteady pouring in the pouring area. The molten steel vortex will not cause the problem of slag entrainment caused by the covering agent involved in the submerged nozzle.

Compared with the prior art, the present invention has the following beneficial effects: no covering agent needs to be added to the molten steel surface in the pouring area, only a small amount of argon gas is required for purging or no argon gas blowing to prevent the secondary oxidation of the molten steel, and the low tonnage pouring condition is effectively avoided The lower covering agent is involved, the tundish structure is simple and easy to realize, which helps to ensure the quality of the billet and reduce the production cost.

Description of drawings

FIG. 1 is a schematic diagram of the structure of the tundish for preventing the covering agent from being involved in the present invention.

In the figure, 1 tundish body, 11 tundish refractory layer, 2 long nozzle, 3 submerged nozzle, 4 tundish cover, 5 weir plate, 51 steel hole, 6 argon gas pipeline, 7 turbulence controller.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

Referring to FIG. 1 , a tundish for preventing covering agent from being involved includes a tundish body 1 , a long nozzle 2 , a submerged nozzle 3 , a tundish cover 4 , a weir plate 5 , an argon gas pipeline 6 and a turbulence controller 7 . An opening is provided above the tundish body 1 , the inner space of the tundish body 1 is used to store molten steel, and the inner side of the tundish body 1 includes a tundish refractory layer 11 .

The tundish cover 4 is arranged on the opening of the tundish body 1, and sealing fibers are arranged at the connection between the tundish cover 4 and the opening. The weir plate 5 is fixedly arranged inside the tundish body 1 along the vertical direction, and divides the interior of the tundish body 1 into a mixing area and a pouring area. The weir plate 5 is provided with a through steel hole 51. The distance between the through steel hole 51 and the inner bottom surface of the tundish body 1 is preferably 0 to 300 mm. The cross section of the through steel hole 51 can be a rectangle or a circle. The value of the side is preferably 50~300mm, and the diameter of the circle is preferably 50~300mm. The through-steel hole 51 is provided with an upward inclination angle from the mixing area to the pouring area, and the angle of the inclination angle (ie, the angle between it and the horizontal plane) is preferably 0° to 80°.

A long shroud hole and an auxiliary hole are adjacently arranged on the tundish cover 4 above the mixing zone, a long shroud 2 is arranged in the long shroud hole, and the auxiliary hole is used for adding a covering agent.

An argon gas pipeline 6 is arranged in the tundish cover 4 above the pouring area. The argon gas pipeline 6 includes a pressure control device and a flow control device. The tundish body 1 is provided with an immersion nozzle 3 at the lower part of the pouring area. The tundish adopts the submerged nozzle slide plate to control the flow instead of the plug rod to control the flow. The reason for not using the plug rod to control the flow is that the plug rod flow control method needs to open holes in the tundish cover for setting the plug rod, and the plug rod is in the flow control process. It needs high-frequency vibration up and down to control the opening. Therefore, if the pouring area is controlled by a stopper, it cannot meet the requirements of complete sealing.

Therefore, the pouring area is composed of the tundish body 1, the tundish cover 4, the weir plate 5 and the sealing fibers to form a fully sealed space. The lower part of the weir plate 5 is provided with a steel hole 51 to connect the mixing area and the pouring area. There are long shroud holes and auxiliary holes, so the mixing area is not completely sealed.

In addition, the turbulence controller 7 is arranged at the lower part of the mixing zone at the position corresponding to the long nozzle 2, and the weir plate 5 is arranged at 1/2~1/4 of the length direction of the tundish body 1 and is close to the submerged nozzle. Therefore, by providing flow control devices such as a turbulence controller and a weir plate inside the tundish, the molten steel can be effectively controlled. The turbulence controller can buffer the kinetic energy of the molten steel flowing out of the long shroud to prevent the molten steel surface from turning over and the exposed liquid surface near the long shroud causing slag entrainment and secondary oxidation. The full mixing in the controller helps the inclusions collide and grow and increase the probability of the inclusions floating up. The weir plate can control the flow line of molten steel in the tundish and increase the residence time of molten steel, thereby obtaining a more reasonable streamline design and also helping to remove inclusions.

According to the above-mentioned tundish for preventing the involvement of the covering agent, the using method specifically comprises the following steps:

First, the pouring area is purged with argon gas, and then molten steel is poured. The molten steel enters the mixing area from the long nozzle 2. Specifically, in the production process, the working pressure of argon is preferably 0.1 to 0.9 MPa, and the amount of argon blowing is 0 to 50 L/min.

After the molten steel level is higher than the through-steel hole 51, preferably when the molten steel level needs to be 50-100 mm higher than the through-steel hole, a covering agent is added to the molten steel surface near the long nozzle 2 through the auxiliary hole, so that the covering agent evenly covers the surface of the molten steel. The molten steel level in the mixing zone near the shroud. This is because the mixing area is an unsealed space, and it is still necessary to pass a covering agent to prevent secondary oxidation of molten steel by air, but at the same time, it is necessary to prevent the covering agent from entering the pouring area.

The molten steel enters the pouring area from the mixing area through the steel hole 51 , and then is discharged from the tundish through the submerged nozzle 3 .

The tundish for preventing the covering agent from being involved in the present invention and the method for using the same can prevent secondary oxidation of molten steel by purging a small amount of argon gas in the sealed space of the pouring area or without blowing argon gas, and avoid using the covering agent in the pouring area. At the same time, the covering agent in the mixing area can be prevented from entering the pouring area by appropriate control means during the pouring process, which can not only effectively prevent the secondary oxidation of molten steel, but also solve the problem that the covering agent is involved in the immersion nozzle.

The above are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the present invention. within the scope of protection of the invention.

Claims (8)

1. A tundish for preventing a covering agent from being involved comprises a tundish body (1), a long water gap (2) and a submerged water gap (3); the method is characterized in that: the tundish also comprises a tundish cover (4) and a weir plate (5);

the tundish cover (4) is arranged on the opening of the tundish body (1), and sealing fibers are arranged at the joint of the tundish cover (4) and the opening; the weir plate (5) is fixedly arranged inside the tundish body (1) along the vertical direction, the interior of the tundish body (1) is divided into a mixing area and a pouring area, and the weir plate (5) is provided with a steel through hole (51); a tundish cover (4) above the mixing area is adjacently provided with a long water gap hole and an auxiliary hole, and a long water gap (2) is arranged in the long water gap hole; an argon pipeline (6) is arranged in the tundish cover (4) above the pouring area, and the tundish body (1) is provided with an immersion nozzle (3) at the lower part of the pouring area.

2. A tundish according to claim 1, wherein the means for preventing the entrapment of the coating agent comprises: the weir plate (5) is arranged at 1/2~1/4 of the tundish body (1) in the length direction and close to the submerged nozzle (3).

3. A tundish according to claim 1, wherein the tundish is arranged to contain a coating agent, and the tundish comprises: the distance between the steel through hole (51) and the inner bottom surface of the tundish body (1) is 0-300mm.

4. A tundish according to claim 1, wherein the tundish is arranged to contain a coating agent, and the tundish comprises: the steel through holes (51) are provided with upward inclination angles from the mixing area to the pouring area.

5. A tundish according to claim 4, wherein the tundish is arranged to contain a solution of the composition: the inclination angle is 0-80 degrees.

6. A tundish according to claim 1, wherein the tundish is arranged to contain a coating agent, and the tundish comprises: the tundish also comprises a turbulence controller (7) and is arranged at the lower part of the mixing area and at the position corresponding to the long nozzle (2).

7. A method of using a tundish according to claim 1, for preventing a coating agent from being entangled, comprising: the method comprises the following steps: firstly, introducing argon into a pouring area for blowing, and then pouring molten steel, wherein the molten steel enters a mixing area from a long water gap (2); after the liquid level of the molten steel is higher than the steel through hole (51), adding a covering agent to the liquid level of the molten steel near the long nozzle (2) through the auxiliary hole; molten steel enters the pouring area from the mixing area through the steel through holes (51) and is discharged out of the tundish through the submerged nozzle (3).

8. The use method of a tundish according to claim 7, wherein the method comprises: and adding a covering agent after the liquid level of the molten steel is 50-100mm higher than the steel through hole.

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