JPH09143537A - Immersion tube for vacuum degassing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve durability and, at the same time, workability because of the restraining effect on slag sticking in improvement of an immersion tube for a vacuum degassing apparatus. SOLUTION: In the immersion tube A for the vacuum degassing apparatus, regular bricks are arranged on the outer peripheral part 2 and holes 5 in the regular bricks are opened to fix these bricks at the lower part. Round or square rods 6 are arranged in an iron core 3 at <=90 deg. upward angle to the iron core 3 and the regular bricks at the outer peripheral part 2 are fixed by inserting the rods into the holes 5 of the brick part. This immersion tube is used for an RH vacuum degassing apparatus by fitting to the lower vessel of 250t RH degassing apparatus and actually used. The erosion of the lower outer peripheral part is restrained with magnesia-carbon bricks and, by this effect, the thermal deformation of the lower iron core is also restrained to drastically improve the damage to the lower part. As a result, the service life can be prolonged 1.5 times and spray-repairing quantity for the lower part can be reduced to half and the effectiveness of this new brick fixing method is confirmed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a dip tube for a vacuum degassing device, which is mainly intended to improve workability due to the effect of suppressing slag adhesion while improving durability.

[0002]

2. Description of the Related Art In recent years, as the mass production of steel has become higher, vacuum refining methods mainly for degassing and C removal, especially RH degassing, D
The H 2 degassing method is generally adopted. The portion of the RH degassing device that is immersed in the molten steel is called a dipping pipe A and generally has the structure shown in FIG. A magnesia-chromium direct bond brick, which has a high resistance to hot wear, is provided on the inner side 1 where the molten steel recirculates, and a high alumina castable is provided on the outer peripheral portion 2 where the heat cycle is severe, together with a support member from the cylindrical iron core 3. Alternatively, they are fixed and arranged by the anchor 4. Various factors such as abrasion of inner bricks, peeling due to spalling, melting loss of outer peripheral castables, intrusion of metal due to cracks, dropout of the lower part, etc. are generated as factors for discarding the immersion pipe A according to use conditions. Most of them are castable parts on the outer circumference, and along with improvement, the repair work such as spraying method is reduced (workability and productivity).
Is a big issue. The idea of applying a fixed brick to the outer peripheral portion is described in JP-A-57-149414, Japanese Utility Model Publication 6-
It is a well-known fact that it has also been applied to 43167 and the like. However, there are various methods for fixing the fixed-sized bricks, and there are many problems in actual use, and stable use has not been achieved. Under such circumstances, the fixing method of JP-A-7-34119 is used in a relatively stable manner, which leads to improvement of durability and reduction of repair work by spraying.

[0003]

In the present dip tube for a peripheral type brick-type vacuum degassing apparatus, melting and dropping of the lower castable portion have not been completely solved, and improvement of this portion is a problem. ing.

[0004]

[Means for Solving the Problems] In order to prevent damage to the castable parts in the lower part, it is premised that the fixed bricks 2 on the outer peripheral part are arranged up to the lower part. As a fixing method, a hole 5 into which a round bar or a square bar 6 can be inserted is formed in advance inside the outer peripheral brick as shown in FIG. At that time, the upward angle should be oriented within 90 degrees. It is necessary that its position substantially coincides with the lower stage of the iron core 3. This hole 5 requires one hole for each brick. Next, a round bar / square bar 6 to be inserted into the hole of the brick is welded to the lower stage of the iron core 3. The number, angle, and position are designed in advance so that the fixed-sized brick 2 can be arranged at a predetermined position. In this way, the lower part of the fixed brick 2 spreads outward and is prevented from falling off.
There are various methods for fixing the upper part because it is not immersed in molten steel, but as a typical method, the iron plate
The fixed brick 2 can be fixed by covering it with. still,
The order of the fixing work of the upper part and the lower part is not specified, but is decided by the fixing method of the upper part and various local circumstances. Further, the material of the regular brick of the outer peripheral portion 2 is not limited, but it is judged that the material of magcarbon or the material of alumina carbon is preferable in view of the fact that the heat resistant spalling property is required.

[0005]

EXAMPLE A dip tube having a 250 t capacity RH vacuum degasser and fixed bricks made of an outer peripheral magnetic carbon material was prepared. (Outline) ・ Iron core size: Inner diameter 950 mm, thickness 15 mm, height 8
00mm ・ Bricks on the outer circumference: Magcarbon, 32 divisions, diameter 25
mm hole with a depth of 30 mm ・ Lower fixing method: Welding a round bar with a diameter of 20 mm to the lowermost step of the iron core at an angle of 60 degrees above ・ Upper fixing method: Fixing the upper part of the brick with an iron plate. Fig. 3 shows an overall view of a dipping tube for a brick-type vacuum degassing apparatus, and Table 1 shows the quality of the materials used. The lining brick and castable construction method was implemented without changing significantly from the conventional method.

[0006]

[Table 1]

[0007]

The RH vacuum degassing apparatus dip pipe according to the present invention was mounted on the lower tank of the 250 tRH degassing apparatus and used.
Melting damage on the outer periphery of the lower part was suppressed by the magcarbon bricks, which also suppressed thermal deformation of the lower iron core and significantly improved damage to the lower part. As a result, the life can be extended 1.5 times, and the amount of spraying and repairing the lower part can be halved.
The effectiveness of this new brick fixing method was confirmed.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of a conventional immersion pipe.

FIG. 2 is a perspective view of the outer peripheral brick of the dipping tube of the present invention.

FIG. 3 is a vertical sectional front view of a dip tube for a vacuum degassing apparatus of the present invention.

[Explanation of symbols]

 A Immersion pipe 1 Inside (lining brick) 2 Outer periphery 3 Cylindrical iron core 4 Supporting metal or anchor 5 Hole 6 Round bar or square bar 7 Iron plate

Claims (1)

[Claims] 1. A submerged pipe A for a vacuum degassing apparatus, in which a fixed brick is arranged on the outer peripheral portion and a fixed brick is provided with a hole for fixing the lower portion, and the iron core has an upper angle of 90 degrees or less with the iron core. 1. A dipping tube for a vacuum degassing device, characterized in that a round brick or a square rod is provided and the fixed brick on the outer peripheral portion is fixed by inserting it into the hole of the brick portion.