JPH0721563Y2 - Vacuum degassing dip tube - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a dip tube of a vacuum degassing apparatus used for degassing and decarbonizing molten steel.

[0002]

2. Description of the Related Art In refining ultra-low carbon with a vacuum degassing apparatus, molten steel is raised in a large diameter immersion pipe having a diameter of 1000 mm or more, and an inert gas is blown into one side of the inner circumference from the bottom of the immersion pipe. , Circulation of molten steel in the immersion pipe,
There is a method of forming a foaming surface on the surface while stirring.

At this time, in order to improve the circulation and stirring efficiency of the molten steel, the blowing gas is blown to one side of the dip tube so as to be biased as much as possible. For this reason, gas bubbles emitted from the tuyere of the ladle sill hit the lower end surface of the dip tube, and the refractory at the lower end of the dip tube is heavily worn, and the dip tube must be replaced frequently.

For such replacement of the immersion pipe, a connecting flange is provided on the upper portion of the immersion pipe to allow the replacement portion to be separated, and a protrusion is formed on the outer surface of the lining brick of the replacement portion to form an irregular shape. Japanese Utility Model Publication No. 2-35801 discloses a structure in which refractory repair is convenient.

[0005]

However, in such a submerged pipe having a vertically separated structure, it is necessary to inhale the outside air from the flanges for connecting the upper and lower members and the cracks of the irregular refractory work body. This also causes a phenomenon of picking up nitrogen into the molten steel, which deteriorates the quality of the treated molten steel.

The object of the present invention is to make it possible to easily perform repair and replacement due to melting damage in a dip tube of a vacuum degassing apparatus having a replaceable joint, and to completely introduce the outside air from the replaceable part. It is to provide a structure that can be prevented.

[0007]

This invention of the vacuum degassing dip tube SUMMARY OF THE INVENTION may, metal core divided into a lower portion core metal forming a flange in the upper core metal and the upper end outer peripheral surface formed with a flange on the lower end outer peripheral surface And an inert gas supply pipe having a tip opening directed to the flange portion is disposed outside the upper core metal, and further, on the outer peripheral surface side of the core metal connecting the both flanges. It is characterized by being provided with an integrated work body of an irregular shaped refractory in which an inert gas supply pipe is buried.

[0008]

[Operation] By removing the flange, it is possible to replace only the lower end of the dip pipe, which has the most severe melting loss, and the introduction of an inert seal gas into the flange and the lower part of the shaped work body prevents the entry of outside air. It can be prevented and the dip tube itself is cooled.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a sectional structure of an immersion pipe provided below a vacuum degassing apparatus according to the present invention.

In FIG. 1, an immersion pipe 1 provided below the vacuum degassing device has an inner brick 4 supported on a core metal 2 by a receiving portion 3 formed on the core metal 2, and a core metal 2.
The irregular shaped refractory work body 5 is integrally formed from the outer surface to the lower side. The cored bar 2 is divided into an upper cored bar 21 having a flange 61 projecting outward at the lower end and a lower cored bar 22 having a flange 62 projecting outward at the upper end, and a bolt They are connected by 7. On the outer surface of the upper core metal 21, there is arranged an inert gas supply pipe 8 that also serves as a cooling material and a sealing material, and its tip opening 9 is directed to the connecting portion by the flanges 61 and 62. Reference numeral 10 denotes a stud that is provided so as to project from the core metal 2, and has a function of an anchor at the time of construction of an indefinite refractory material.

Since the dip tube 1 of the present invention has the above-mentioned structure, as shown in the right half of the dip tube 1 shown in FIG. After the fixed refractory work body 5 is peeled off, the bolts 7 of the flanges 61 and 62 are removed to remove the lower end portion of the immersion pipe 1 for repair and regeneration.

FIG. 3 shows the procedure for repair and regeneration.

First, as shown in FIG. 3 (a), the lower end of the dip tube 1 which has been melt-damaged to the state shown in FIG. 2 is removed by a breaker, and an unshaped refractory is applied. In addition to forming a surface condition convenient for repairing, the bolts 7 of the flanges 61 and 62 are removed to separate the separated portion including only the lower core metal 22 from the upper portion and carry it out to the preparation place.

Next, as shown in FIG. 3 (b), a lower mandrel 22 for replacement, to which a lining brick 41 has been attached in advance at a preparation place, is replaced with an upper mandrel 21 via flanges 62 and 61.
Attach to. Then, a frame material 11 for constructing an irregular refractory is attached to the same shape as the outer shape shown in FIG. Then, the refractory slurry is press-fitted from the castable pressure feed port 12 to regenerate the immersion pipe 1 shown in FIG.

It is preferable that the flange and the end opening of the inert gas supply pipe are installed below the molten metal surface when the molten steel is immersed.

[0016]

The present invention has the following effects.

(1) The life of the immersion tube can be extended by simply replacing the lower end of the immersion tube which has been melted and damaged.

(2) Since the joining portion is sealed with an inert gas, the outside air does not enter, the nitrogen is not picked up by the refining molten steel, and the quality of the steel product is not deteriorated.

(3) The inert gas for sealing has a cooling function and protects the irregular-shaped refractory construction body and prolongs its life.

[Brief description of drawings]

FIG. 1 is a view showing a sectional structure of an immersion pipe according to an embodiment of the present invention.

FIG. 2 is a diagram showing a melting damage state of a lower end portion of the immersion pipe.

FIG. 3 is a diagram showing a procedure for repairing a melt-dissipation immersion pipe.

[Explanation of symbols]

 1 Immersion pipe 2 Mandrel 21 Upper mandrel 22 Lower mandrel 3 Receiving part 4 Inner brick 5 Unshaped refractory construction 61,62 Flange 7 Bolt 8 Inert gas supply pipe 9 Opening 10 Stud 11 Frame material 12 Pressure feed port

Claims (1)

[Scope of utility model registration request] 1. A has a core metal which is divided into a lower portion core metal forming a flange in the upper core metal and the upper end outer peripheral surface formed with a flange on the lower end outer peripheral surface, the outside of the upper core metal, the tip opening Is provided with an inert gas supply pipe directed to the flange portion, and further, an integral construction of an indefinite refractory material in which the inert gas supply pipe is embedded on the outer peripheral surface side of the core metal connecting the both flanges. A vacuum degassing dip tube with a body.