JPH0135890B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a reflux pipe and a joint between the reflux pipe and an immersion pipe in an RH degassing device.
This is related to RH degassing equipment and aims to improve the durability of the lower tank.

Conventionally, in RH degassing equipment, drawing number 1,
As shown in Figure 2, the reflux pipe 2a is located at the bottom of the lower layer 1a, and is immersed in the molten steel in the ladle, and connects two immersion pipes 8a at the bottom for raising and lowering the molten steel, and the inside is It is made of refractory bricks, and the exterior is made of iron skin 4a. Therefore, it is strongly influenced by the internal and external thermal temperature difference as well as the influence of the circulating flow of molten steel, and is an important part that is replaced most frequently due to erosion, second only to the service life of the immersion pipe 8a.

The refractory constituting the reflux pipe 2a is constructed of highly corrosion-resistant refractory bricks in an annular shape, and the lowest brick layer 3a is connected to the flange 5 of the outer steel shell 4a as shown in the figure.
so as to be able to engage with the inward flange portion 6a of a.
Annular corner notch 3 where the lower edge of the outer periphery has dropped corners
A shape that forms a′ is used. The lowermost brick layer 3a of the reflux pipe 2a and the immersion pipe 8
The flange 5a of the iron skin 4a is integrated with the flange 11a of the other iron skin 10a by fastening the flange 5a of the iron skin 4a and the flange 11a of the other iron skin 10a with refractory mortar interposed at the joint surface of the iron skin 4a with the uppermost brick layer 9a. Note that 7a is a stepped shoulder portion of the inward flange portion 6a, and 12a is a monolithic refractory.

By the way, in the above-mentioned conventional RH degassing device, the immersion tube 8a has the shortest lifespan and is generally replaced quite frequently. The lower brick layer 3a is affected by the distortion of thermal stress due to the temperature difference between the inner side and the outer side of the iron skin 4a, or the refractory and the iron skin 4a.
Due to the influence of force distortion due to the difference in thermal expansion between the It is extremely common for partial flaking to occur, or similar flaking to occur during removal work of metal, slag, etc. adhering to the inner surface of the reflux pipe 2a.
(a) This deteriorated the durability of the entire lower tank 1a, forcing its use to be terminated at an early stage.

The present invention has been made in view of the above, and is an object of the present invention to provide an RH degassing device as described below to eliminate the various drawbacks of the conventional art.

This inventive device will be described in detail with reference to embodiments shown in FIGS. 3 to 5 of the drawings. First, 1 is a lower tank constructed of highly corrosion-resistant refractory bricks, and two reflux pipes 2 made of highly corrosion-resistant refractory bricks are connected together at the bottom of the tank, and the outside is made of iron skin 4. has been done. The flange 5 at the lower end of the steel shell 4 is an out-inward flange having an inward flange portion 6. and the reflux pipe 2
The lower end surface of the lowermost brick layer 3 is configured to be flush with the upper end surface of the shoulder portion 7 of the inward flange portion 6. Next, 8, 8 are both the above-mentioned reflux pipes 2, 2
The two immersion pipes for raising and lowering molten steel are connected to the lower part of the pipe and are made of highly corrosion-resistant refractory bricks, and the outside is covered with a steel shell 10 having a flange 11 matching the flange 5 at the upper end. It is worn.
The upper end surfaces of the uppermost brick layer 9 of both the immersion tubes 8 are flush with the upper end surface of the flange 11 of the steel shell 10. Therefore, in this invention, an annular refractory 13 having approximately the same thickness as the inward flange portion 6 is provided between the lowermost brick layer 3 of both the reflux pipes 2 and the upper end surface of the uppermost brick layer 9 of both the immersion pipes 8. The two iron skins 4 and 10 are connected by intervening flanges 5 and 11, respectively, and are assembled together by fastening flanges 5 and 11 of both iron skins 4 and 10. The annular refractory 13 is divided into a plurality of segments as shown in FIG. 5 of the drawings, and refractory mortar is interposed at the upper and lower joint surfaces of the annular refractory 13. . Note that 1 in the figure
2 is a monolithic refractory.

As described above, this invention makes the lower end surface of the lowermost brick layer of the reflux pipe flush with the upper end surface of the step shoulder of the inward flange portion of the steel shell, and Since it is connected to the upper end surface of the uppermost brick layer through an annular refractory with approximately the same thickness as the inward flange, the lowermost brick layer of the reflux pipe has the same strength as before. An annular refractory with approximately the same thickness as the inward flange is interposed between the lowermost brick layer of the reflux pipe and the uppermost brick layer of the immersion pipe. This has the outstanding effect of preventing cracks caused by internal and external heat temperature differences and molten steel circulating flow, and significantly improving the service life of the circulating pipe and, by extension, the lower tank.

In addition, when replacing the immersion pipe, by disposing of the intervening annular refractory, problems such as cracking and peeling of the lowermost brick layer of the reflux pipe are completely eliminated, and the service life of the lower tank is longer than that of the conventional 400 to 500 channels. This has the excellent effect of making it possible to significantly extend the channel to 600 to 700 channels.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view of the conventional device, Fig. 2 is an enlarged longitudinal sectional view of the main parts of the same, Fig. 3 is a longitudinal sectional view showing an embodiment of the invented device, and Fig. 4 is an enlarged longitudinal sectional view of the main parts of the same. The top view and FIG. 5 are enlarged perspective views of the same annular refractory. 1, 1a... lower tank, 2, 2a... reflux pipe,
3, 3a...lowest brick layer, 3a'...annular corner notch, 4,4a...iron skin, 5,5a...flange,
6, 6a... Inward flange portion, 7, 7a... Step shoulder portion, 8, 8a... Immersion pipe, 9, 9a... Top brick layer, 10, 10a... Iron shell, 11, 11a...
...flange, 12, 12a ... monolithic refractory, 1
3...Annular refractory, 14...Crack.

Claims (1)

[Claims] 1. The lower end surface of the lowest brick layer of the reflux pipe is flush with the upper end surface of the step shoulder of the inward flange of the steel shell,
An RH characterized in that an annular refractory having approximately the same thickness as the inward flange portion is interposed and connected between the lowermost brick layer and the upper end surface of the uppermost brick layer of the immersion pipe.
Degassing equipment.