JPH101712A - Brick structure of degassing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce erosion speed of bricks in a circulating flow tube by dividing a brick at uppermost step into an upper and the lower parts at the uppermost part of the circulating flow tube in at least the center side of a vessel and inclining downward the boundary surface of both brick parts to molten steel flowing passage side. SOLUTION: The lower vessel 1 has cylindrical circulating flow tubes 3, 4. The circulating flow tube 3 lines the bricks at three or four steps, and each boundary surface between brick 5a at the uppermost step and a brick 5b just below the brick at the uppermost step has the inclination so that the friction force becomes large because the boundary area becomes larger than a horizatal boundary area. Direction of the inclination is formed as downward to the molten steel flowing passage side. The reason for dividing the brick at the uppermost step into two parts, is that the division into small parts is more profitable to restrain the crack caused by structural spalling, etc., progressed from the apparatus. The eroding speed of the brick at the uppermost step is reduced and the service life of the lower vessel 1 is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum degassing apparatus, and more particularly to an improvement in a brick structure of an RH degassing apparatus.

[0002]

2. Description of the Related Art RH degassing equipment used for vacuum refining of molten steel is a method in which the inside of a tank is evacuated, the molten steel is sucked in from one dipping pipe, discharged from the other dipping pipe, and the molten steel in the pot is circulated in the tank. This is a facility for mainly degassing the entire molten steel. Among them, the recirculation pipe of the lower tank connected to the immersion pipe is important in that it is a main part that determines the life of the lower tank because the molten steel and the slag are largely melted. In the brickwork of this part, the boundary surfaces of the bricks were all horizontal as shown in FIG.

In the figure, 1 is an RH lower tank, 2 is a side wall brick,
3 and 4 are reflux pipes, 5c is a top brick of a conventional reflux pipe, 6
Denotes a second-stage brick of the reflux pipe, 7 denotes a lowermost brick of the reflux pipe, 8 denotes a brick, and 9 denotes a flange.

[0004]

In the brick structure according to the prior art, when the uppermost brick of the reflux pipe is eroded to some extent, the uppermost brick floats by violent flow of molten steel, and as a result, the uppermost brick is lifted from other parts. Since the erosion rate is increased, the service life of the lower tank is limited with low durability.

[0005]

Means for Solving the Problems The present invention advantageously solves the above-mentioned problems, and the gist of the present invention is to provide a reflux pipe brick structure for RH degassing equipment, in which at least the uppermost brick of the reflux pipe at the center of the tank. Is divided into upper and lower parts, and a boundary surface between the divided upper brick and lower brick has a boundary surface with the brick inclined downward toward the molten steel channel side.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a front sectional view showing the RH lower tank brick structure of the present invention. In FIG. 1, the lower tank 1 has cylindrical reflux pipes 3 and 4. The reflux pipe 3 has three or four levels of bricks, and the boundary between the uppermost brick 5a and the lowermost brick 5b is inclined, so that the boundary area is larger than when the boundary is horizontal and the frictional force is larger. Is set to be large. The direction of the inclination is inclined so that the molten steel channel side is downward. When the direction of the inclination is reversed, as shown in FIG. 3, as the erosion of the uppermost brick progresses, the boundary area decreases, and the frictional force decreases. Conventional top brick 5c
The reason for dividing into two is that, when divided into small parts, the propagation of cracks due to structural spalling or the like that proceeds from above can be suppressed. In FIG. 3, 5a 'indicates the uppermost brick of the reflux pipe whose inclination of the boundary surface is opposite to the present invention, and 5b' indicates the uppermost lower brick whose inclination of the boundary surface is opposite to the present invention.

Accordingly, the brick structure according to the present invention is characterized in that the uppermost brick of the reflux pipe is divided into upper and lower parts, and a boundary surface between the divided upper and lower bricks is inclined downward toward the melting channel. It is valid.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

[0010]

An example in which the present invention is actually applied to 300 tRH is shown below.

The lower tank to which the present invention is applied has a steel bath inner diameter of about 2200 mm, and an immersion pipe inner diameter of 650 mm. The total height of the reflux tube is 830 mm. The size of the reflux tube brick is 250 mm in width and the height is about 180 mm to 380 mm,
It is divided into 28 parts in the circumferential direction. The height of the top brick of the conventional reflux tube is 350 mm, and the top brick of the reflux tube of the present invention is obtained by dividing the conventional product at a substantially central position with an inclination of about 12 ° so that the molten steel channel side is downward (5a, 5b). ). If the inclination angle is too large, an acute angle portion is generated in the brick and a crack is easily formed. Therefore, the inclination angle is desirably 30 ° or less.

When the RH operation was performed with the brick structure of the present invention, the erosion rate of the reflux pipe brick was reduced, and the lower tank life was improved by 10 to 20% from the conventional 400 ch.

[0013]

In the conventional brickwork structure, as the uppermost brick in the reflux pipe is eroded, the uppermost brick floats due to the strong flow of molten steel, and as a result, the erosion speed becomes higher than in other parts. , Had become a factor limiting the service life of the lower tank with low durability, but with the brick structure of the present invention,
The erosion rate of the uppermost brick in the reflux pipe was reduced, the service life of the lower tank was improved by 10 to 20%, and the operating rate and cost of the degassing process were greatly improved.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a reflux pipe brick structure of a degassing facility according to the present invention.

FIG. 2 is a front sectional view showing a reflux pipe brick structure of a conventional degassing facility.

FIG. 3 is a partial sectional view showing a state in which the inclination of the boundary surface of the reflux pipe brick is opposite to that of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... RH lower tank 2 ... Side wall brick 3, 4 ... Reflux pipe 5a ... Reflux pipe uppermost step upper brick 5b ... Reflux pipe lowermost step lower brick 5a '... Boundary surface inclination reverse to that of the present invention, upper level pipe upper brick 5b ': Uppermost lower brick of the reflux pipe whose inclination of the boundary surface is opposite to that of the present invention 5c: Conventional uppermost brick of the reflux pipe 6 ... Second brick of the reflux pipe 7 ... Lowermost brick of the reflux pipe 8 ... Brick 9 ... Flange

Claims (1)

[Claims] In a reflux pipe brick structure of an RH degassing facility, at least in a brick structure at an uppermost part of a reflux pipe on a tank center side, an uppermost brick is vertically divided, and a boundary between the divided upper brick and lower brick. A brick structure characterized in that the surface is inclined downward toward the molten steel channel.