JPH04154683A - Production of nozzle for blowing gas - Google Patents

Abstract

PURPOSE:To readily form gas holes of a nozzle for blowing gases at an accurate regular interval without clogging by spirally winding and superposing refractory powder containing a binder in a state thereof laminated on a vanishing sheet, pressurizing the sheet, heating the laminate and making the vanishing sheet disappear. CONSTITUTION:Refractory powder 1 containing an adequate amount of a binder is laminated on a vanishing sheet 2, spirally wound, superposed in this state, pressurized and then heated to make the vanishing sheet 2 disappear. If through- holes 3 are formed at any places in the vanishing sheet 2, spacers having the action of supports are preferably formed in gas holes 4 with the through-holes 3 to reinforce the gas holes 4. The resultant nozzle for blowing gases has the spiral gas holes 4 passing therethrough formed in the vertical directions. In use, the peripheral part is preferably covered with a dense refractory 5 so as to prevent the gases from leaking from the side. An outer peripheral iron shell 6 and a gas inlet pipe 7, as necessary, are installed in the same manner as that in a conventional method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of manufacturing a gas blowing nozzle that is used by being attached to the bottom or side of a molten steel refining vessel.

[Prior Art] Molten steel is refined by blowing gas into various molten steel containers.

There are various types of gas blowing nozzles used for this purpose. In the ladle, a nozzle (Japanese Patent Publication No. 52-72
Publication No. 2) is used. Since the amount of gas blown into a converter is large, a nozzle having a vertically penetrating thin tube or slit (Japanese Unexamined Patent Publication Nos. 58-167717 and 62-13408) is used.

[Problems to be Solved by the Invention] However, none of these conventional gas blowing nozzles is easy to manufacture. For example, in the case where the voids between refractory particles are used as gas vents, the number of voids between the refractory particles must be increased in order to improve gas permeability, which deteriorates the structural strength and leads to a decrease in corrosion resistance.

Nozzles used in converters and the like have a long shape with a height of about 1000 to 1500 mm, depending on the thickness of the lining, and it is difficult to form vertically penetrating thin tubes or slits without blocking them. do not have. Therefore, there is a large amount of reservations, leading to high manufacturing costs.

Furthermore, a method has been proposed in which a thin steel tube is buried and cast as a gas vent (Japanese Patent Laid-Open No. 57-200533).

Although this method is easy to manufacture, since pressure molding is not performed, the tissue filling rate is insufficient and the corrosion resistance is poor.

SUMMARY OF THE INVENTION The present invention aims to solve the above-mentioned speed-limiting problem in the manufacture of gas injection nozzles. This method of producing a gas blowing nozzle is characterized in that the fugitive sheet is spirally wound in a laminated state on a fugitive sheet, and after pressurization, the fugitive sheet is made to disappear by heating.

The material of the refractory powder l is not particularly limited, and examples include alumina, silica, silica-alumina, mullite, magnesia, spinel, zirconia, zircon, silicon carbide, which have been conventionally used in the manufacture of gas injection nozzles. The main material is one or more selected from silicon nitride, carbon, etc.

The type m binder is not particularly limited, and organic, inorganic, and organic-inorganic composites conventionally known as binders for refractories can be used. The content in the refractory powder is approximately 1 to 10% by weight, and is determined within this range depending on the type of binder.

In addition to the above, the refractory powder may also contain metal powder, clay,
Auxiliary raw materials such as chromium oxide and refractory ultrafine powder may be added.

The fugitive sheet 2 may be any material as long as it disappears by heating, and it does not matter whether it is a natural product or a synthetic material. For example, synthetic resin, synthetic fiber, natural fiber, paper, timber board, etc. can be used. The thickness thereof is related to the width of the slit that serves as the gas blowing hole, but it is laminated onto a sheet 2, which will be described later, and after being spirally wound, it is pressurized. Although not shown in the figure, pressurization is performed by placing it in a mold, applying pressure by putting it in a rubber mold, or using a rubber press. When placed in a mold and pressurized from above, the fugitive sheet 2 is deformed as the refractory powder 1 is compressed, but the gas holes formed by this deformation become larger in the vertical direction by the amount of deformation. This has the effect of making it difficult for molten steel to enter the gas holes.

After pressurizing as described above, the entire molded product is heated.

The heating temperature is at least higher than the temperature at which the fugitive sheet 2 melts or burns. As the fugitive sheet 2 is heated and dissipated, voids that become gas holes are formed.

This heating also has the effect of hardening the molded body. Further, when the heating temperature is, for example, 1000° C. or higher, the molded body can obtain a sintering effect.

The width of the gas hole of the nozzle obtained by the present invention is 0.1~
4 mm is preferred. If the thickness is less than 0.1 mm, the gas permeability will be poor, and the starting portion of 4 mm may be buried in the refractory powder. In that case, after pressurizing or heating to eliminate the fugitive sheet 2, cut the top and bottom surfaces of the molded object,
It is preferable to completely expose the portions corresponding to the gas holes.

As shown in the figure, the fugitive sheet 2 may have through holes 3 of an appropriate size formed at various locations. Among the gas holes formed in the fugitive sheet 2, the through holes 3 are filled with refractory powder l,
This filled part acts as a spacer and has the effect of improving the strength of the gas hole.

FIG. 2 shows an example of the use of the gas blowing nozzle manufactured according to the present invention. In FIG. 2, (A) is a longitudinal cross-sectional view, and (B) is a cross-sectional view taken along the line XX of (A).

The gas blowing nozzle manufactured by the present invention has a second
As shown in the figure, a spiral gas hole 4 penetrating vertically is formed. During use, it is preferable to cover the outer periphery with a dense refractory material 5 in order to prevent gas leakage from the side surfaces. Furthermore, as is conventional, the outer skin 6 and the gas introduction pipe 7 may be attached as necessary.

[Effect]

According to the method of the present invention, it is possible to obtain a gas blowing nozzle in which the spiral gas hole penetrates in the vertical direction and has a large amount of gas permeation.

One of the reasons for manufacturing difficulties in the conventional method is that it is difficult to provide the gas holes 4 at regular intervals. This is particularly difficult in the case of long gas injection nozzles. On the other hand, in the present invention, forming is performed by rolling up and overlapping, so if the thickness of the refractory powder 1 and the fugitive sheet 2 are kept constant, it is easy to form gas holes at the same distance regardless of the length of the gas injection nozzle. can be formed into

Furthermore, when the fugitive sheet 2 is manufactured by forming through holes 3 at various locations, the strength of the gas holes 4 is improved.

[Example] Example 1 An alumina powder prepared by adding 3 wt % of a 30 wt % aqueous solution of calcium ligninsulfonate as a binder and kneading it was placed on a polyvinyl chloride sheet (305 mm long x 129 mm wide).
5 mm x 1.10 mm thick) to a thickness of 15 mm, and then spirally wound. Next, with the removal of this Neil sheet, the refractory was fired and the height was 300mm and the diameter was 2mm.
A 00 mm gas blowing nozzle was obtained. The longitudinal section of the refractory has six gas holes with a width of 1 mm and an interval of 14.5 mm.

The production in this example was rapid and the gas holes were precisely spaced.

Example 2 In the production of Example 1 above, ten through holes each having a diameter of 10 mm were formed in the polyvinyl chloride sheet at approximately equal intervals. Other conditions were the same as in Example 1. The through-holes formed spacers that acted as supports within the waste holes, reinforcing the gas holes.

For each of the gas injection refractories obtained in Examples 1 and 2 above, a monolithic refractory was further cast around the outer periphery to make the whole into a trapezoidal shape, and an outer skin and a gas introduction pipe were formed. After installation, the 250 was used as a plug for blowing gas into the ladle. As a result, these plugs fully demonstrated the effect of molten steel refining by stirring molten steel.

[Effects] As described above, according to the present invention, in manufacturing a gas blowing nozzle penetrating in the vertical direction, gas holes can be formed without clogging and at accurate equal intervals. Moreover, its production is easier than conventional methods.

[Brief explanation of the drawing]

FIG. 1 is a perspective view illustrating the manufacturing method of the present invention. FIG. 2 shows an example of the use of the gas blowing nozzle manufactured according to the present invention. In FIG. 2, (A) is a longitudinal cross-sectional view, and (B) is a cross-sectional view taken along the line X--X of (A). Fireproof powder... Bow Disappearing sheet... 2 holes...
・3 Gas holes...4 Patent applicant Harima Ceramic Co., Ltd. No. 11, Figure 2

Claims (2)

[Claims] (1) A refractory powder 1 containing an appropriate amount of binder is layered on a fugitive sheet 2 and wound in a spiral, and after pressurization, the fugitive sheet 2 is made to disappear by heating. A method of manufacturing a gas injection nozzle. (2) The method for manufacturing a gas blowing nozzle according to claim 1, wherein through-holes 3 are formed at various locations in the fugitive sheet 2.