JP2001262219A - Method for lining-working of lower vessel in vacuum degassing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the lining-working time for applying a fluid refractory in a lower vessel in a vacuum degassing apparatus. SOLUTION: In the lining-working of the lower vessel in the vacuum degassing apparatus provided with two circulating flow tube holes, a core part corresponding to the whole body of the lining of the lower vessel and having a tapered shape downward from the bottom part to the circulating flow tubes and having a material supplying hole at almost the center part is used, and the fluid refractory is poured from both of the gap between the core and the side wall surface to be lined and the material supplying hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for lining a lower tank of a vacuum degassing apparatus.

[0002]

2. Description of the Related Art Vacuum degassing devices of RH type, DH type, etc.
This is a molten steel treatment device that performs degassing treatment and component adjustment of molten steel in the steelmaking industry. From the trend toward higher quality steel products in recent years,
Its role is important.

[0003] In order to save labor in the construction of a vacuum degassing device, it has been attempted to convert conventional brickwork into irregular refractories. For example, JP-A-8-12452, JP-A-9-2
As described in JP 79222, JP 9-279223 A and the like.

[0004] Amorphous refractory conversion of a vacuum degassing apparatus is being promoted mainly in a lower tank which is significantly worn due to direct contact of molten steel during operation. FIG. 3 is a longitudinal section showing a conventional construction method for lining the lower tank.

[0005] The lower tank (1) has a reflux pipe hole (2a), (2b) at the bottom.
Are provided at two places. After the core (3a) is provided in this reflux pipe, the irregular-shaped refractory (4b) is poured in, and after the bottom lining is constructed, the core (3c) is placed on the bottom lining and the irregular-shaped refractory is placed. (4c) is poured and the lining of the side wall (6) is constructed.

[0006]

In the above-mentioned conventional method, the lining of the side wall must be performed after the lining of the bottom portion, so that the number of steps is increased and the laying time is long. Therefore, it is conceivable to perform the construction at once using a core corresponding to the entire inner surface of the lower tank.

However, the bottom of the lower tank has a complicated shape having a reflux pipe hole, and the bottom is poured in a horizontal direction, so that the filling rate of the lining cannot be sufficiently ensured.

[0008] The bottom of the lower tank is a place where the wear action by the molten steel flow largely acts. Underfilling of the bottom significantly reduces the lining life.

[0009]

SUMMARY OF THE INVENTION According to the present invention, there are provided two reflux pipe holes.
In the lining work of the vacuum degassing device provided in the lower tank, the core provided with a tapered lower throttle from the bottom to the reflux pipe and provided with a material supply hole almost in the center of the bottom corresponding to the entire lower tank lining. A method for lining a lower tank of a vacuum degassing device, wherein an irregular refractory is poured from both a core and a side wall lining surface and from the material supply hole.

Referring to FIG. 1 and FIG. 2 of a sectional view taken along line AA of the present invention, the present invention uses an integral core (3a) extending over a side wall (6) and a bottom (5). Since the inner surface of the lining is bent from the side wall to the bottom or from the bottom to the reflux tube, the core has a corresponding corner portion, but the core (3a) used in the present invention is formed from this bottom. A taper (7a) and (7b) for the lower throttle is provided over the reflux pipe. As a result, the resistance of the amorphous refractory (4a) at the time of pouring is reduced, and the refractory is easy to be degassed.

However, even in the bottom part (5), the reflux pipe holes (2
Poor filling of the portion located between a) and (2b) cannot be solved by the above method. Therefore, in the present invention, the irregular-shaped refractory (4a) is poured also from the material supply hole (8) provided substantially at the center of the bottom.

[0012] By pouring from the material supply hole (8), the lining at the bottom is filled vertically, and the material supply hole (8)
Is a degassing hole, so that the filling rate is improved.

[0013] In the conventional method of FIG. 3, there is a time difference between the construction of the bottom and the side wall, so that there is a problem that a lining interface between the bottom and the side wall is generated, and molten steel slag intrudes into this interface, and this portion is prematurely damaged. In the present invention, there is no interface in the lining due to the integral construction, and there is no problem of the preceding erosion.

According to the present invention, in the use of an integral core,
A uniform and dense lining construction can be obtained. In addition, the use of the integrated core significantly reduces the construction time as compared with the conventional method.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. 1 and FIG.

The core (3a) has an outer diameter dimension commensurate with the thickness of the lower tank lining. In the present invention, a taper (7a) for the lower throttle is provided at the corner from the bottom to the reflux pipe. Is preferably 22.5 to 67.5 ° with respect to the vertical line.

FIG. 1 shows a linear tapered surface, but the tapered portion may have a smooth curve in order to minimize the occurrence.

A material supply hole (8) is provided substantially at the center of the bottom of the core (3a). It is preferable to connect the hopper (9) to the material supply hole (8) from the viewpoint of workability.

At the time of pouring, the irregular-shaped refractory (4a) is vibrated according to a standard method to improve the filling rate, though not shown. Generally, a vibrator is mounted on the inner surface of the core (3a), but a rod-shaped vibrator may be inserted into the irregular refractory (4a). Further, the attachment of the vibrator to the core and the rod-shaped vibrator may be used in combination.

[0020] When pouring the irregular refractory, it is feared that the irregular refractory at the bottom overflows from the material supply hole due to the pressing pressure of the irregular refractory poured from between the core and the side wall lining surface. After pouring into the bottom, the pouring is made to flow between the core and the side wall lining with the material supply hole (8) closed.

After pouring the amorphous refractory, the core is removed upward when a certain strength of the construction body is secured after curing and drying of the amorphous refractory. Providing the taper at the corners of the core also has an effect of preventing damage to the lining construction when the core is removed. At the same time, the angle of the corner portion of the lining construction body is reduced, and there is also an effect that corner breakage damage during use of the lining is prevented.

Although not shown in the drawing, a heat insulating board, a permanent layer, and the like may be provided between the outer shell (10) and the lining, if necessary. This is no different from the prior art.

The above-described method of the present invention can be applied not only to a new lining for the lower tank, but also to lining repair. In the lining repair, a core is installed on the inner surface of the remaining lining, and the lining is applied by the method according to the present invention.

The heating and drying is performed by means such as a bus burner and electric heating after removing the core (3a), the hopper (9), the core receiver (11) and the like.

[0025]

FIG. 2 shows an embodiment of a lower tank of an RH type vacuum degassing apparatus.
It was lined with a structure similar to that of FIG. The thickness of the floor is about 600mm, and the thickness of the side wall is about 450mm. The inner diameter of the reflux tube is 600 mm.

The core used corresponds to the entire lower tank lining, and has a tapered lower throttle from the bottom to the reflux pipe. A material supply hole having an inner diameter of 200 mm was provided substantially at the center of the bottom, and a hopper was connected to the material supply hole. In order to further improve the filling rate of the amorphous refractories, a vibrator was attached to the inner surface of the core and the hopper.

Alumina-magnesia amorphous refractory was poured between the core and the side wall lining surface and from both of the material supply holes, and the entire lower tank lining was lined. Drying is
This was performed by covering the upper opening of the lower tank and blowing a flame from a gas burner from below the reflux pipe hole.

[0028] As a result, the required construction time is reduced by 30% or more compared to the conventional method in which the side wall is constructed after the bottom is constructed. Also,
The amorphous refractory at the bottom did not have the filling of the side wall lining and the color of the refractory, and excellent durability was obtained.

For comparison, the refractory is cast only from between the core and the lining surface of the side wall. When the refractory is poured from the center of the bottom, 10 to 30 m is particularly necessary for the lining at the bottom.
Macro bubbles such as m were generated. Further, in the present invention, the porosity of the entire construction body was 15%, but in this comparative example, the porosity of the bottom lining was 17%.

[0030]

According to the present invention, in the formation of an irregular refractory in a vacuum degassing apparatus, the present invention can reduce the time required for forming the irregular refractory, and the conversion of the irregular refractory in the vacuum degassing apparatus becomes more effective. Amorphous refractory in vacuum degassing equipment is expected to spread more and more in the future in terms of labor saving in lining work, and in this sense the value of the present invention is great.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a conventional example.

[Explanation of symbols]

 1 Lower tank 2a, 2b Recirculation pipe hole 3a, 3b Core 4a, 4b, 4c Irregular refractory 5 Bottom 6 Side wall 7a, 7b Taper of lower throttle 8 Material supply hole

Claims (1)

[Claims] 1. A method for lining a lower tank of a vacuum degassing device having two reflux pipe holes, the lower tank having a tapered lower throttle from the bottom to the reflux pipe and corresponding to the entire lower tank lining. Using a core provided with a material supply hole and pouring an irregular refractory between the core and the side wall lining surface and from both of the material supply hole; Construction method.