JPS59136413A - Rh degasser - Google Patents

Abstract

PURPOSE:To prevent cracks from generating in the lowest refractory layer of annular tube, by providing the annular refractory of almost the same thickness as that of the inward flange part of the steel shell of circulating tube between the lowest refractory layer of circulating tube and the top surface of the top refractory layer of immersion tube. CONSTITUTION:An annular refractory 13 of almost the same thickness as that of the inward flange part 6 of steel shell of circulating tube 2 is provided between the lowest refractory layer 3 of the circulating tube 2 of a bottom vessel 1 and the top surface of the top refractory layer 9 in RH degasser and they are, in a contact manner, connected. By this contacting manner, fastening of the flange 5 of the steel shell 4 of circulating tube 2 to the flange 11 of the steel shell 10 of immersion tube 8, is integrally constituted. Thus, the crack of the lowest refractory layer 3 of annular tube 2 due to the temperature difference between inside and outside and the circulating flow of molten steel can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an RH degassing device that improves and improves the reflux pipe and the joint between the reflux pipe and the immersion tube in the RH degassing device, and is aimed at improving the durability of the lower tank. It is something.

Conventionally, in the RH degasser, as shown in Figure 1-2 of the drawing, the reflux pipe 2a is located at the bottom of the lower layer /a,
Two immersion pipes fa, which are immersed in the molten steel in the ladle and raise and lower the molten steel, are connected at the bottom, and the inside is made of refractory bricks and the outside is made of iron shell lla. 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.

The refractory constituting the reflux pipe 2a is made of highly corrosion-resistant refractory bricks, and the lowermost brick layer 3a engages with the inward flange part Oa of the flange Sa of the outer steel shell 11a, as shown in the figure. In order to enable the fitting, a shape having an annular corner notch 3a/ with a rounded corner at the lower part of the outer periphery is used. And the lowermost brick layer 3a of the reflux pipe 2a
A refractory mortar is interposed at the joint surface between the uppermost brick layer qa of the immersion pipe 11a and the 7 langes Sa of the iron skin 11a and the 7 langes lla of the other iron skin/Qa are fastened to form an integrated structure. There is. Note that 7a is the inward flange portion Oa
The step shoulder portion /, 2a is a monolithic refractory.

By the way, in the above-mentioned conventional RH degasser, the immersion pipe J'a has the shortest service life and is generally replaced quite frequently. The lowermost brick layer 3a is affected by the influence of thermal stress distortion due to the temperature difference between the inner side and the outer side of the steel shell 11a, or the influence of force distortion due to the difference in thermal expansion between the refractory and the steel shell 11a, especially as shown in Fig. 2. Annular corner notch 3 a/
There are many cracks/l that start from the corners of the reflux pipe 2, which may cause natural partial peeling or
The removal work of metal, slag, etc. adhering to the inner surface of a often causes similar flaking, and this lowermost brick layer 3a
Due to some defects in the reflux pipe 2az and the lower tank/a
This deteriorated the overall durability of the product, forcing its use to be terminated at an early stage.

The present invention has been made in view of the above, and it is an object of the present invention to provide an RH degassing device as described below to eliminate the above-mentioned conventional road defects.

The embodiments of this inventive device shown in Figures 3 to S will be described in detail. First, / 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. has been done. The flange S at the lower end of the iron skin t is
It has 7 lunges facing the inside and outside (out-inward) with an inward-facing flange part B. And the reflux pipe-
The lower end surface of the lowermost brick layer 3 is configured to be flush with the upper end surface of the step layer section 7 of the seven inward flange sections B. Next, 2g is two immersion pipes for raising and lowering the molten steel, which are to be connected to the lower part of the above-mentioned mountain flow pipes 2, 2, and are made of highly corrosion-resistant firebrick, and the outside is connected to the above-mentioned 7 plungers at the upper end. A steel shell 10 with flanges // compatible with S is applied. The upper end surfaces of the uppermost brick layers 9 of both the immersion tubes 8 are flush with the upper end surfaces of the 7 lunges of the steel shell 10. Therefore, in the present invention, between the lowermost brick layer 3 of the mountain flow pipe 2 and the upper end surface of the uppermost brick layer of both immersion pipes 8, an annular refractory with approximately the same thickness as the inward 7 flange part B is provided. 3 intervening and connecting, 7 lunges of both iron skins 'I, IQ! , // are integrated by fastening. As shown in Figure S of the drawing, the annular refractory /3 is divided into a plurality of parts in a sederment style, and refractory mortar is used to intervene on the upper and lower joint surfaces of the annular refractory /3. be done. Note that / and 2 in the figure are monolithic refractories.

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 stepped layer of the inward seven flange portions of the steel shell, and the lower end surface of the lowermost brick layer of the reflux pipe and the immersion pipe The lowermost brick layer of the reflux pipe is connected to the upper end surface of the uppermost brick layer with an annular refractory having approximately the same thickness as the seven inward flange portions mentioned above. An annular refractory that does not have an annular corner cutout that degrades strength and has approximately the same thickness as the inward 7-flange section 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 the conventional one.
There is an excellent effect in that it is possible to significantly increase the number of particles to 600 to 7,000 compared to h.

[Brief explanation of the drawing]

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. 3 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. /, /a,,・lower tank,! , 2a...reflux pipe, 3.3
a... Bottom brick layer, 3a... Annular corner notch, Ge,
17 a, , Iron skin, S, Sa...7 lunge, Otsu, Otsu a・1. Inward 7 flange part, 7, 7 (1... step layer part, i, ga... dip pipe q, 9 //... top brick layer, 10/10a, ..., iron skin, // , //a
,・,7 Lunge,/Tips/2a・. - Monolithic refractories, /3, - Annular refractories, /ll. ...Crack, Patent applicant: Tokyo Ceramics Co., Ltd. Figure 1 - Figure 3

Claims (1)

[Claims] The lower end surface of the lowermost brick layer of the reflux pipe is flush with the upper end surface of the step layer of the inward flange portion of the steel shell, and between the lowermost brick layer and the upper end surface of the uppermost brick layer of the immersion pipe. An RH degassing device characterized in that the inward flange portion is connected to the inward flange portion through an annular refractory having approximately the same thickness.