JPH02434Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an immersion tube for a vacuum degassing device that has excellent structural strength.

In vacuum degassing equipment such as RH type and DH type,
The immersion tube that sucks and discharges molten steel into a vacuum tank is subject to significant wear and tear due to erosion by the molten steel and slag. Therefore, when the amount of refractory remaining in the immersion tube decreases, the immersion tube is removed using a flange and replaced with a newly prepared immersion tube.

The immersion tube is constructed by using a metal cylinder as a core material and providing refractories on the outer and inner peripheries of the core. Since the installation in the vacuum chamber is a hanging structure in which the upper end of a metal cylinder is attached to the reflux pipe with a flange, the supporting capacity of the refractory decreases at the end of its use, and the immersion pipe may become damaged due to the refractory falling off. Life expectancy is decreasing.

Conventionally, refractories have been supported by providing studs, holders, etc. on metal cylinders, but adding more of these supports reduces the heat resistance of the immersion tube.
This is undesirable because it causes cracking of the refractory due to thermal expansion.

This invention solves the above conventional problems,
In an immersion pipe in which a monolithic refractory or a monolithic refractory is provided on the inner and outer peripheries of a metal cylinder, a plurality of through holes are formed at intervals in the metal cylinder. This immersion tube for a vacuum degassing device is characterized in that the inner circumference of the metal cylinder and the monolithic refractory on the outer circumference are integrated through the through hole.

An embodiment of the present invention will be described based on the drawings. In the vertical cross-sectional view of FIG. A shaped refractory 4 is provided via a shaped refractory 3b. In this example, the inner circumferential side is made of shaped refractory 4 because the inner hole of the immersion tube is made of molten steel.
This is because slag circulates and the wear and tear is significant compared to the outer periphery, so a shaped refractory with high corrosion resistance is used. The reason for interposing the monolithic refractory 3b between the metal cylinder 2 and the shaped refractory 4 is to eliminate the void that inevitably occurs between the shaped refractory 2 and the metal cylinder 2 during construction when the shaped refractory 4 is provided. This is to fill in the holes and fix the shaped refractories 4. The shaped refractory 4 is supported by a receiver 5 provided around the inner periphery of the lower end of the metal cylinder 2. The outer periphery of the monolithic refractory 3a is supported by a large number of studs 6 implanted in the metal cylinder 2. Refractory 3a, 3
There are various ways to support b and 4 in addition to the above-mentioned support 5 and stud 6, but the present invention is not limited to these in any way.

The monolithic refractories 3a and 3b are castable refractories made by casting alumina cement, phosphate, sodium silicate, etc. into a refractory aggregate as a binder, and castable refractories made by using a refractory aggregate with fireclay, a binder, etc. There are plastic refractories that are cast in the form of clay mixed with water and stamped materials that are applied with a rammer, but castable refractories with good workability are most preferred. Shaped refractories are fired or unfired refractory bricks manufactured by conventional methods;
Alternatively, it may be a precast product obtained by casting in advance, but fired refractory bricks are most preferred from the viewpoint of corrosion resistance.

In the present invention, a plurality of through holes 7 are formed in the metal cylinder 2 at intervals, and the monolithic refractories 3a, 3b on the inner and outer peripheries of the metal cylinder 2 are passed through the through holes 7.
to integrate. The shape of the through hole 7 is that of the metal cylinder 2.
A circular shape including an ellipse is preferred so as not to reduce the strength of the material and to obtain maximum voids. The size of the through hole 7 is not particularly limited, and the effect can be recognized even if it is quite small, but an example of a case where the through hole 7 is circular is 10 to 100 mmφ. The shaped refractory 4 is also supported by coming close to the metal cylinder 2 due to thermal expansion due to preheating during use or before use, so the size of the through hole 7 is smaller than the back surface of the shaped refractory 4. It is preferable. The number of through holes 7 is appropriately determined depending on the size, shape, etc. of the through holes 7, and it is preferable that they are formed evenly in the circumferential direction at intervals.

FIG. 2 is a perspective view of the metal cylinder 2 used in the embodiment shown in FIG.

By the way, when an immersion pipe is used in an RH type vacuum degassing apparatus, although not shown in the figure, a gas pipe for introducing an inert gas into the molten steel is generally buried. When the refractory is made of a material with high gas permeability, the metal cylinder 2 serves as a shield plate that prevents the inert gas to be ejected into the inner hole of the immersion tube from leaking to the outer circumferential side. For this reason, if there is a concern that gas leakage to the outer circumferential side is caused by forming the through hole 7, it is better to position the through hole 7 below the gas pipe, that is, below the metal cylinder 2, as shown in Figure 2. . Since refractory material falls off from the bottom end, the life of the immersion tube will be extended if the structural strength is improved primarily from the bottom.Also, in order to not reduce the strength of the metal cylinder, it is recommended that the hole be located at the bottom. preferable.

The immersion pipe of this embodiment has a monolithic refractory material 3b on the inner periphery.
Since the layer thickness is thin and the strength is low, the strength of the inner circumferential monolithic refractory 3b is significantly improved by integrating with the outer circumferential monolithic refractory 3a.

The embodiment shown in FIG. 3 is an immersion tube in which a metal cylinder 2 is provided with monolithic refractories 3a and 3b on both the inner and outer peripheries without using a shaped refractory, and a through hole 7 is formed in the metal cylinder 2. It was formed.

In addition, a through hole may be formed in the metal cylinder for an immersion tube in which both the inner and outer peripheries of the metal cylinder are provided with a shaped refractory via an amorphous refractory.

The immersion tube of the present invention configured as described above supports the monolithic refractories provided on the inner and outer peripheries of the metal cylinder with through holes, unlike metal supports which have poor heat resistance. Even if the refractory becomes damaged during its unused period, its supporting capacity will not be lost.
In addition, when the damage to the immersion pipe progresses from the bottom end and reaches the metal cylinder, molten steel and slag enter between the inner and outer peripheries of the refractory with the metal cylinder as the boundary, causing damage to the immersion pipe. However, according to the present invention, the monolithic refractory filled in the through holes has the effect of suppressing this intrusion.

When a shaped refractory is used as in the embodiment shown in FIG. 1, a small gap between the shaped refractory and the metal cylinder must be filled with the monolithic refractory during construction. However, in the present invention, monolithic refractories are supplied through the holes into the gaps between the inner and outer circumferences of the metal cylinder, and the filling is more complete than in the conventional immersion tube.

As described above, the present invention can extend the life of the immersion tube without increasing the number of metal supports with poor heat resistance, and with a simple structure in which a through hole is provided in the metal cylinder. As a result, using the immersion pipe of the present invention reduces construction and repair costs for the immersion pipe.
By reducing the number of replacement steps, the operating rate of the vacuum degassing equipment is significantly improved.

When the immersion tube according to the present invention was tested on an actual machine, it withstood more than 120 charges during operation of a vacuum degassing device, while the conventional type had less than 90 charges.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of an embodiment of the present invention, FIG. 2 is a perspective view of the metal cylinder in FIG. 1, and FIG. 3 is a vertical sectional view showing another embodiment of the present invention. 1...Flange, 2...Metal cylinder, 3a, 3
b... Monolithic refractory, 4... Fixed refractory, 5...
Receipt, 6... Stud, 7... Clear hole.

Claims (1)

[Claims for Utility Model Registration] 1. In an immersion pipe in which a monolithic refractory or a monolithic refractory is provided on the inner and outer peripheries of a metal cylinder, a plurality of shaped refractories are provided in the metal cylinder. A immersion tube for a vacuum degassing device, characterized in that through-holes are formed at intervals from each other, and the inner circumference and the outer circumference of the monolithic refractory of a metal cylinder are integrated through the through-holes. 2. The immersion tube for a vacuum degassing device according to claim 1 of the registered utility model, in which the through hole is provided below the metal cylinder.