JPH0684522B2 - Vacuum degassing equipment Snorkel repair method - Google Patents

Description

The present invention relates to a method for repairing a snorkel part of a vacuum degassing device.

[Conventional technology]

In a DH-type or RH-type vacuum degassing apparatus used for molten steel treatment, a snorkel that sucks up or discharges molten steel between a ladle and a degassing tank has a remarkable wear on the inner peripheral surface due to the molten steel flow. Therefore, a snorkel is repaired by using a core and inserting a repair material between the inner peripheral surface of the snorkel and the core. However, according to this repair, there is a problem in that the gas ejection holes provided on the inner peripheral surface of the snorkel for promoting suction of the molten steel flow into the degassing tank are blocked by the repair material.

Therefore, as shown in FIG. 2, in the repair using the core 4, a repairing method in which a void forming material 6 made of a granular material is put in a portion below the gas ejection holes 3 and then a repairing material 7 is put thereon. Is proposed. For example, it is as disclosed in JP-A-61-116286. According to this method, after repairing, when the core 4 is melted by the contact of molten steel by using the snorkel 1, the void forming material 6 falls and the gas ejection holes 3 are exposed to prevent the gas ejection holes 3 from being blocked. It

[Problems to be Solved by the Invention]

However, the above method has a drawback that the portion below the gas ejection hole cannot be repaired. In addition, recently, a non-aqueous repair material has been used for repairing the snorkel portion, but this repair material has excellent corrosion resistance, but has a problem that the repair time is long because of slow curing.

[Means for Solving the Problems]

The present invention is a method for solving the above-mentioned conventional problems in repairing the snorkel part of the vacuum degassing device. Insert the core into the snorkel, and fill the space between the lower end of the snorkel and the lower part of the gas ejection hole with a hydraulic repair material using alumina cement as a binder between the core of the snorkel, and then at the location of the gas ejection hole. It is characterized in that a void-forming material is introduced and then a non-aqueous repair material having a pitch and / or a synthetic resin as a binder is filled thereabove.

The present invention will be described in more detail with reference to FIG.

The snorkel 1 to be repaired has a gas supply pipe 2 buried therein, and a gas ejection hole 3 thereof is opened in the inner peripheral surface of the snorkel 1.

Insert the core 4 into the snorkel 1 after use from the bottom. A space corresponding to the thickness of the repair material is provided between the snorkel 1 and the core 4. The core 4 is made of, for example, a metal that is lost by contact with molten steel. As in Japanese Patent Laid-Open No. 54-107404, a core having a sleeve-shaped refractory as an exterior may be used. The lower end of the core 4 prevents the repair material from leaking, for example, by using a receiving metal 5. After setting the core 4 as described above, first, between the lower end of the snorkel 1 and the lower part of the gas ejection hole 3, a hydraulic repair material 17 using alumina cement as a binder is filled. The proportion of alumina cement is preferably about 1 to 30 wt% with respect to the refractory aggregate. Hydraulic repair material 17
Uses alumina cement as a binder, so that it cures faster than non-aqueous repair materials. The repair material located below the snorkel 1 may fall if it is not sufficiently hardened. However, by using a hydraulic repair material that cures quickly in this lower portion, the repair time is greatly shortened in the present invention. It

Next, the void forming material 6 is introduced into the gas ejection holes 3. The material of the void forming material 6 is not particularly limited as long as it has heat resistance, and for example, refractory powder, natural sand, metallurgical slag, glass powder, ceramic fibers, asbestos and other granular materials and / or fibrous materials. Can be used. When a metallic core is used, the void forming material 6 drops due to the melting of the core. Even when the core is not melted and the void-forming material 6 remains, the particles or the fibers of the void-forming material 6 become ventilation holes, and the gas ejection holes are not blocked. In order to ensure the drop due to the melting of the core or the ventilation between the particles and the fibers, it is preferable that the void forming material 6 has a large granular diameter and a large fiber diameter. Moreover, the gas ejection holes 3 are formed by the void forming material 6.
The void forming material 6 so that the part of
Is preferably filled with a certain allowance in the height direction.

In the use of the snorkel 1, when the core 4 is melted due to the contact with molten steel, the void forming material 6 falls and the gas ejection hole 3 is exposed. In addition, a core made of a refractory material coated on a metallic core, or a core made of a refractory material as a whole does not melt away, but the void forming material 6
Between the particles or fibers of the gas become air passages, and the gas ejection holes 3
Is never blocked.

After the space forming material 6 is charged as described above, the drainage system repair material 27 is filled above the space forming material 6. The non-aqueous repair material 27 uses pitch and / or synthetic resin as a binder. Specific examples of the synthetic resin include thermoplastic phenol resin, furan resin, polyurethane resin and the like. Above all, a phenol resin having a large fixed carbon content is preferable. A thermosetting resin may be used in combination with this thermoplastic resin. The amount of pitch and / or synthetic resin added to the refractory aggregate is, for example, 2 to 30 wt.
%. The non-aqueous repair material 27 is subjected to furnace heat to be fluidized by melting the binder, and after being filled, it becomes a carbon bond structure having excellent corrosion resistance and spalling resistance due to carbonization of the binder.
The snorkel's gas ejection holes and their surroundings are significantly more melted and damaged than other parts, but the non-aqueous repair material 27 also has an excellent effect of improving the corrosion resistance around the gas ejection holes.

In the above hydraulic repair material 17 and non-aqueous repair material 27,
The type of aggregate is not particularly limited, and for example, one selected from magnesia, spinel, chrome ore, alumina, silica, alumina-silica, zircon, zirconia, silicon carbide, or brick waste obtained by aggregating these, or the like. The main material is two or more types. In the case of the non-aqueous repair material 27, there is no problem of digestion, so dolomite, lime, etc. may be used.

The hydraulic repair material 17 and the non-aqueous repair material 27 are, for example, clay, silica flour, carbon, refractory ultrafine powder, wetting agent, dispersant, metal powder, antioxidant, and sintering agent in addition to the above aggregates. One or more selected from a foaming agent, slaked lime, silica sol, alumina sol, organic fiber, inorganic fiber, metal fiber and the like may be added. Further, a binder other than the ones limited by the present invention can be used together.

Although not shown in the figure, in the present invention, the filling of the repair material and the injection of the void forming material are performed by inserting a repair large from above between the snorkel cores or by press-fitting the repair material from the inner surface of the core. Known filling device (for example, JP-A-61
No. 116286, JP-A No. 62-120419, and Japanese Utility Model Laid-Open No. 1-177259).

〔Example〕

In Example 1 and Comparative Examples 1 to 3, the suction pipe (internal diameter 800 × height 2000 mm) corresponding to the snorkel portion of the 300 t DN type vacuum degassing apparatus was repaired. In Example 2, the dip pipe and the reflux pipe (internal diameter 500 × height 1600 mm) corresponding to the snorkel portion of the RH type vacuum degassing apparatus of 300 tons were repaired.

In Example 1, a core was used in which the outer circumference of the metallic cylinder was covered with magnesia-chrome mineral brick having a thickness of 50 mm, and the portion facing the gas ejection hole was opened. Other examples and comparative examples used metallic cores.

Example 1 The following hydraulic repair material was added, and after filling from the lower end of the snorkel to the lower part of the gas ejection hole with the hydraulic repair material, 5 mm
A void-forming material composed of sized magthesia grains was introduced below, and the site of the gas ejection hole was covered with the void-forming material at a height of about 100 mm. Then, the following drainage system repair material was filled on it.

Example 2 The following hydraulic repair material was added, and the area from the lower end of the snorkel to below the gas ejection holes was filled with the hydraulic repair material. After that, a void-forming material composed of limestone grains sized to 3 mm or less and alumina-silica fiber was introduced, and the site of the gas ejection hole was covered with the void-forming material at a height of about 100 mm.
Then, the following non-aqueous repair material was filled thereon. In the case of the RH-type vacuum degassing device, since the gas ejection pipe is provided on the immersion pipe side, the portion filled with the non-aqueous repair material is above the gas ejection hole of the immersion pipe and the entire reflux pipe.

Comparative Example 1 The portion below the gas ejection hole was filled with magnesia grains having a size adjusted to 5 mm or less. Then, a non-aqueous repair material having the composition shown in the above-mentioned Example 1 was filled above the above.

Comparative Example 2 The area of the gas ejection hole was filled with alumina particles having a size adjusted to 3 mm or less, and the upper and lower portions thereof were filled with the hydraulic repair material having the composition shown in Example 1 above.

Comparative Example 3 The gas ejection hole was filled with magnesia grains having a size adjusted to 5 mm or less, and the upper and lower portions thereof were filled with the non-aqueous repair material having the composition shown in Example 1 above.

In each of the above examples, the snorkel can be immediately used after repairing the snorkel by filling the lower part with the hydraulic repair material that cures quickly, and the periphery of the gas ejection hole has high corrosion resistance. It was possible to obtain an excellent repair effect. In addition, in Example 1, since the magnesia grains were used as the void-forming material, the grain boundaries of the magnesia grains served as ventilation paths to prevent the gas ejection holes from being blocked. In Example 2, the metal core was melted and lost due to contact with the molten steel, and the void forming material composed of the limestone grains and the alumina-silica fiber was dropped to prevent the gas ejection holes from being blocked.

On the other hand, Comparative Example 1 is inferior in durability after repair because the portion below the gas ejection hole cannot be repaired. Comparative Example 2 is inferior in corrosion resistance around the gas ejection holes. In Comparative Example 3, since the lower part was also filled with the non-aqueous repair material, the repair material at the lower end of the snorkel portion to be used immediately dropped after the repair, so that it took a considerable time to complete the repair.

Incidentally, the present invention is not limited to the above examples, for example, specific material of hydraulic repair material, non-aqueous repair material, within the scope of the present invention other than those shown in each example. A composition may be used.

〔The invention's effect〕

 The effects of the present invention are as follows.

The entire inner peripheral surface of the snorkel can be repaired without blocking the gas ejection holes.

By filling the lower part of the snorkel with a hydraulic hardening material that cures quickly, a non-aqueous repair material that cures slowly can be retained, and the repair time can be greatly shortened.

The non-aqueous repair material improves the corrosion resistance around the gas ejection holes. The water-curable repair material is inferior to the non-aqueous repair agent in corrosion resistance, but the gas spouted inside the snorkel flows upward, probably because the hydraulic repair material is filled downward, The surrounding corrosion resistance does not decrease.

As described above, according to the repairing method of the present invention, not only can the gas ejection holes be prevented from being blocked, but the entire inner peripheral surface of the snorkel can be repaired, the repairing time is short, and the corrosion resistance around the gas ejection holes is excellent. The effects are extremely large, such as reducing the number of repair steps and improving the operation rate of the vacuum degassing device.

[Brief description of drawings]

Each of the drawings is a vertical sectional view showing a method of repairing a snorkel part of a vacuum degassing device, and FIG. 1 is a method of an embodiment of the present invention,
FIG. 2 shows a conventional method. 1 ... Snorkel, 6 ... Void forming material 2 ... Gas supply pipe, 7 ... Repair material 3 ... Gas ejection hole, 17 ... Hydraulic repair material 4 ... Core, 27 ... Non-aqueous repair material 5 ... Receiving

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideyuki Ishikawa, Inventor Hideyuki Ishikawa 1-1-1 Edamitsu, Hachimanto-ku, Kitakyushu, Fukuoka (72) Inventor, Taizo Tashiro, Takasago City, Hyogo Prefecture 1-3-1 Niihama, Arai Town Harima Ceramics Co., Ltd. (72) Yoshinobu Kambe 1-3-1 Niihama, Niihama, Arai Town, Takasago City, Hyogo Prefecture (72) Inventor Yasuko Hayashida Takasago City, Hyogo Prefecture 1-3-1 Niihama, Arai Town Harima Ceramics Co., Ltd.

Claims (1)

[Claims] 1. In hot repair of a snorkel having a gas ejection hole on an inner peripheral surface thereof, the snorkel is inserted into a core, and a portion between the lower end of the snorkel and a lower portion of the gas ejection hole is inserted between the snorkel cores. After filling with a hydraulic repair material that uses alumina cement as a binder, insert a void forming material at the gas ejection hole site, and then fill a drainage repair material with a pitch and / or synthetic resin as a binder above it. A method of repairing a snorkel part of a vacuum degassing device, which is characterized by: