JP7249106B2 - Inner body and manufacturing method thereof - Google Patents

Description

The present invention relates to an internal body such as a gas blowing plug or an upper nozzle fitted to a tuyere installed in a molten metal container such as a ladle or a tundish.

The gas blowing plug blows gas into the molten metal, and the upper nozzle is installed at the bottom of the molten metal vessel to discharge the molten metal. These are attached by mating tuyeres located at the bottom of the molten metal vessel. In this specification, such a thing fitted to the tuyere and installed is called an "interior body".

Tuyeres generally have a longer life than their internal bodies. That is, the internal bodies such as the gas blowing plug and the upper nozzle are replaced several times for the same tuyere. At this time, the inner body is adhered to the inner hole surface of the tuyere via a joint material in order to prevent leakage of molten metal from the space between the inner body and the tuyere. And when replacing the inner body, the inner hole surface of the tuyere must have a shape that matches or is similar to the outer shape of the inner body, or the unevenness of the surface is less than the thickness of the joint so that the inner body is in close contact with the joint. It is necessary to maintain the smoothness of

However, when the inner body is removed, at least a part of the joint material and inclusions such as molten metal or slag remain on the inner hole surface of the tuyere, and the smoothness of the inner hole surface of the tuyere is reduced. may not be guaranteed.

The remaining joint material is generally removed by mechanical destruction using, for example, the device and cleaning method disclosed in Patent Document 1, and various other devices and methods. However, such inconsistent residue removal operations require an unexpected amount of time and effort and can disrupt the service cycle of the molten metal vessel. Furthermore, the tuyere itself is often damaged during such mechanical destruction or removal. Damage to the tuyeres can lead to reduced life of the tuyeres and surrounding refractory layers, or an increased risk of leakage of molten metal from the tuyeres themselves and around the tuyeres.

JP-A-7-256440

The problem to be solved by the present invention is to prevent the joint material used when fitting and attaching the interior body to the tuyere from remaining on the inner hole surface of the tuyere, or to reduce the extent to which it remains. be.

The outermost peripheral surface of the inner body, which is in contact with the inner hole surface of the tuyere through the joint material, is roughly divided into (a) the form of a metal plate (the outer surface of the metal case) and (b) the form of a refractory material.

The present invention is based on increasing the adhesiveness between the metal plate or refractory material on the outermost peripheral surface of the interior body and the joint material when the interior body is removed from the tuyere.

The adhesive layer adheres the adhesive layer and the refractory or metal plate and joint material of the inner body by sintering or reaction, mechanical entanglement, etc. It adheres by infiltration and subsequent solidification.

That is, the present invention provides the following inner body 1 to 4 and inner body manufacturing method 5 to 6 .
1.
An inner body fitted and attached to a tuyere of a molten metal container, wherein at least a region of the outermost peripheral surface of the inner body that is in contact with the inner hole surface of the tuyere through a joint material is attached to the tuyere. It has a layer (hereinafter referred to as "adhesion layer") that has a function to adhere to the joint material after receiving heat from being attached and used , and the adhesion layer contains a silicate derived from water glass . interior body.
2.
The adhesive layer contains at least one type of refractory raw material particles of alumina, alumina-silica, zircon, spinel, or silicic acid with a particle size of 0.5 mm or less, or metal particles in total of 10 mass. % or less, the inner body according to 1 above.
3.
3. The inner body according to 2 above, wherein the metal particles are iron or iron-based alloy particles.
4.
3. The internal body according to any one of 1 to 3 above, wherein the adhesive layer has a maximum thickness of 0.5 mm or more and 2 mm or less.
5.
7. The method for manufacturing an inner body according to any one of 1 to 6 above, wherein an adhesive layer is formed on the outermost peripheral surface of the inner body using a material containing a silicate derived from water glass , and the adhesive layer is formed on the outermost peripheral surface of the inner body. A method of manufacturing an inner body, comprising a step of heat-treating at 100° C. or higher after forming.
6.
6. The method for producing an internal body according to 5 above, wherein the water glass has a SiO ₂ /R ₂ O (R: alkali metal) molar ratio of 2.35 or more and 3.35 or less.

According to the present invention, the adhesive layer adheres the joint material and the metal plate or refractory material on the outermost peripheral surface of the inner body by sintering or reaction, mechanical entanglement, etc. By infiltrating into the refractory structure and then solidifying, it is possible to bond the joint material to the outermost peripheral surface of the inner body.
As a result, when the inner body is removed from the molten metal vessel, the joint material is removed together with the inner body, so that it can be prevented from remaining on the inner hole surface of the tuyere, or the remaining joint material can be reduced. can.
As a result, it is possible to eliminate or reduce the need for work and processes such as applying mechanical impact to the inner hole surface of the tuyere, which was conventionally necessary to remove the remaining joint material. can reduce the time and effort required. Also, damage to the tuyeres can be prevented or reduced.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional image diagram showing an embodiment of an inner body of the present invention, in which (a) is a gas blowing plug, the outermost peripheral surface of which is in the form of a metal plate (metal case), and (b) is a gas blowing plug. , the outermost peripheral surface of which is in the form of a dense refractory, and (c) is the upper nozzle, which is composed only of the refractory. It is a cross-sectional image diagram explaining a state when pulling out the plug for gas blowing (internal body) of FIG.1(b) from a tuyere. FIG. 5 is a cross-sectional image diagram illustrating a state when a gas blowing plug (comparative example) having no adhesive layer is pulled out from a tuyere.

FIG. 1 shows an embodiment of the inner body of the present invention.
The inner body 1 shown in FIG. 1(a) is a gas blowing plug, the outermost peripheral surface of which is a metal plate (metal case) 2, and the outer peripheral side of the metal plate (metal case) 2 which is the outermost peripheral surface. is provided with an adhesive layer 3. A dense refractory layer 4 is disposed on the inner peripheral side of the metal plate (metal case) 2, and a breathable refractory layer 6 is provided on the inner peripheral side of the dense refractory layer 4 with a sealing material 5 interposed therebetween. are placed. A gas introduction pipe 7 is connected to the permeable refractory layer 6 so that gas is discharged from the upper end surface of the permeable refractory layer 6 .

The inner body 1 shown in FIG. 1(b) is a gas blowing plug, the outermost peripheral surface of which is a dense refractory layer 4, and the outermost peripheral surface of the dense refractory layer 4 is adhered to the outer peripheral side. It has layer 3. A metal plate (metal case) 2 is arranged on the inner peripheral side of the dense refractory layer 4 , and an air-permeable refractory layer 6 is arranged on the inner peripheral side of the metal plate (metal case) 2 .

The inner body 1 shown in FIG. 1(c) is an upper nozzle and is composed only of a refractory material. An adhesive layer 3 is provided on the outer peripheral side (outermost peripheral surface) of the upper nozzle made of this refractory material.

These inner bodies 1 are fitted and attached to the tuyeres 8 of the molten metal container via a joint material 9, as shown in FIG. 2 for the inner bodies 1 of FIG. Since the adhesive layer 3 provided on the outermost peripheral surface of the inner body 1 is a layer having a function of adhering to the joint material 9, the inner body 1 is attached from the tuyere 8 as shown in FIG. When pulled out, the joint material 9 does not remain in the tuyere 8, and the joint material 9 can be pulled out together with the interior body 1 inside it.

The specific functions of this adhesive layer are mainly as follows.
1. The adhesive layer softens due to the heat received during use, and adheres to the metal plate or refractory material on the outermost surface of the inner body and the joint material.
2. Similarly, the contact area increases by biting into those irregularities,
3. increase mechanical entanglement or frictional resistance,
4. The inner body and the adhesive layer receive heat, causing sintering and reaction (generation of a third substance) between the adhesive layer, the metal plate or refractory on the outermost surface of the inner body, and the joint material, respectively form or increase the binding state of

If the outermost surface of the inner body is refractory, the chemical composition of the refractory and the chemical composition of the adhesive layer, the chemical composition of the adhesive layer and the chemical composition of the joint material, etc., will change when they are mixed when receiving heat. can be estimated from the phase diagram, etc., and adjustments can be made to lower the melting point or generate minerals.
At the time the inner body is removed, these temperatures are such that these low-melting substances solidify or the minerals stabilize, thereby causing or increasing adhesion to each other.
For example, if the outermost peripheral surface of the inner body is refractory and the joint material is alumina, alumina-silica, spinel, or zircon, etc., general refractory composition, silicates, alkali metal oxides, alkaline earth An adhesive layer containing a metal oxide or the like may be used.

If the outermost peripheral surface of the inner body is a metal plate, the metal structure or surface of the metal plate, such as metal that oxidizes or corrodes the grain boundary or surface of the metal in the adhesive layer, or fuses at high temperature, is added. Adhesion to the adhesive layer can be strengthened by including the component that causes the formation. These components include phosphorus, sulfur, iron, iron-based alloys, and the like.
Again, at the time of removal of the inner body, these temperatures are such that they are in a solidified or stabilized state, so that they adhere to each other or increase in adhesion.

In the following, an adhesive layer containing a silicate derived from water glass is used, and a metal plate and an alumina-silica castable refractory are used as the outermost peripheral surface of the inner body. Explain the form.

Water glass is suitable not only for refractories, but also for metal plates, which are more difficult to apply than refractories. has a viscosity of

Water glass is represented by a general molecular formula of R ₂ O.nSiO ₂ .mH ₂ O, where R represents an alkali metal such as Na, K or Li, and coefficient n represents the number of moles of SiO ₂ . Industrially, those with n in the range of 0.5 to 4.2 are produced, and in general, those with n of about 2 to 4 are often used. m represents the number of moles of H ₂ O and is commercially available in the range of about 2.0 to 3.5.

This water glass is _No. 2 water glass (viscosity about 200 mPa s) or No. 3 _water glass (viscosity about 80 mPa·s) is most preferably used.
In addition, the chemical composition of this water glass No. 2 after heat treatment at 1050 ° C. in accordance with JIS R 2212-1 to 5 is 51% by mass or more and 61% by mass or less of SiO ₂ and 17% by mass or more and 25% by mass of alkali metal oxides. % by mass or less.

At the time of coating the outermost peripheral surface of the inner body, the inner body is generally in the shape of a truncated cone, so regardless of the direction in which the inner body is placed, one of the surfaces will be downward, that is, in the direction of gravity. For this reason, water glass must have shape retention to the extent that it does not run off during application.
Further, in order to thinly apply the water glass to the entire outermost peripheral surface of the inner body by coating or the like, its spreadability is also necessary, so it is preferable that the viscosity is neither too low nor too high.
Primarily for these reasons, water glass No. 2 or No. 3 is preferred.

Next, the method of manufacturing the inner body will be described. .Apply in a thickness of 5 to 2 mm.

The thickness of the adhesive layer is determined by adhesion to the joint material, and reaction between the joint material and the outermost surface of the interior body (especially in the case of refractory materials), integration, or absorption into the pores. Considering the change, it is preferable that the distance is about 0.5 mm or more and about 2 mm or less.
The extent of this change varies depending on the chemical composition of the adhesive layer itself, the chemical composition of the joint material and outermost surface of the interior body, the particle composition, or physical properties such as porosity. The thickness may be appropriately optimized.

In addition to No. 2 water glass, other than No. 2 water glass, water glasses with different SiO ₂ /R ₂ O ratios (No. 1, No. 3, No. 4), and R In addition to Na, K and Li can also be used. In addition to water glass, powdery alkali silicate can also be dissolved in water.
Various organic substances such as dextrin and celluloses, various clays, inorganic or organic fibers, etc. can be added to the material of these adhesive layers in order to enhance the function of increasing viscosity, shape retention, and the like.

After providing the adhesive layer, after curing or air drying for about one day, heat treatment is performed at a temperature of 100° C. or higher, preferably at a temperature of 300° C. or higher using a dryer. This heat treatment strengthens the water glass layer (adhesive layer).

In order to improve the strength of this layer, the adhesive layer may be added with a generally used alkali silicate curing agent, such as oxides or hydroxides containing components such as Mg and Ca.
Furthermore, in this adhesive layer, in order to improve shape retention and extensibility, strength, fire resistance, corrosion resistance, etc. during the installation work of this layer, the size is less than the thickness of the adhesive layer to be set, preferably Refractory raw material particles having a size (particle size) of 0.5 mm or less can be included. Further, in order to maintain or secure the ductility and the like, the size (particle size) of the refractory raw material particles is more preferably about 0.2 mm or less. Alternatively, in order to strengthen the contact surface with the joint material, the surface may be roughened so as to form some unevenness.

These refractory raw material particles contribute to sintering and reaction between particles, the main constituent material (silicate) in the adhesive layer, the refractory or joint material of the inner body, the metal plate, etc., and contribute to the adhesion layer and the reaction. In order to ensure or enhance the adhesiveness to a metal plate or the like, oxides, metal particles, or the like are preferable.

If the content of the refractory raw material particles increases, the spreadability and uniformity may decrease, and discontinuous parts may occur in the adhesive layer, causing cracks. is preferably about 10% by weight or less in total in the adhesive layer.

These refractory raw material particles can contain one or a plurality of different types regardless of whether they are artificial or natural such as sintering and electrofusion. Specific examples of these raw materials include alumina-based materials mainly composed of corundum, mullite, sillimanite-based materials, kaolinite and other clays and chamotte, alumina-silica-based materials such as rholite and china stone, zircon-based materials, spinel-based materials, quartz, and cristobalite. , tridymite, silicate-based materials such as glass, etc., and in the case of metals, particles of iron or iron-based metals can be used.
Furthermore, inorganic or metal fibers may be included to reinforce the adhesive layer.

There is no particular reason for limiting the type and composition of the refractory layer of the interior body and the joint material, and the composition of the adhesive layer may be selected according to the application.

<Example>
Examples of embodiments of the present invention will now be described with reference to specific examples.

In this embodiment, among the metal plate or refractory material that forms the outermost peripheral surface of the inner body, a metal plate having relatively low adhesiveness to the adhesive layer is used as the base material, and the adhesive layer is provided on the surface of the metal plate, Furthermore, a refractory layer corresponding to a joint material was placed on the surface of the adhesive layer, and the shear strength of the sample after heat treatment was measured. This refractory layer had almost the same composition as the mortar used as a joint material when attaching the interior body to the tuyere, except for the grain size composition. Therefore, it can be inferred that the test results for samples using this refractory layer are similar to those for actual mortar.

Specifically, the samples were prepared by the following method.
A flat metal plate of 120 x 70 x 1.2 ^mmt is placed on the bottom of the metal frame, a liquid containing refractory raw material particles in water glass is applied to the surface of the metal plate with a brush, and a castable refractory material is applied to 30 mm. It was cast while vibrating to a height of . After curing (hardening and natural drying) for one day in this state, heat treatment was performed in an electric furnace at 1200° C. for 1 hour.

The castable refractory has a maximum particle size of 5 mm, a particle size of about 50% by mass, an Al ₂ O ₃ content of about 90% by mass, a CaO content of about 2% by mass, and 1000 ° C. An alumina-magnesia type material having an apparent porosity of about 16% after heat treatment and a bending strength of about 4 MPa after heat treatment at 1000° C. was used.

The workability in applying the water glass (coating workability to the metal plate) was evaluated by ◯ when the spreadability was good and by Δ when the spreadability was somewhat difficult. This "slightly difficult" case includes not only difficulty in coating, such as requiring force in the coating work itself, but also a case in which it is difficult to ensure uniformity in a small amount of work, that is, a case in which so-called uneven coating tends to occur.

As an indicator of the strength of adhesion between the adhesive layer and the castable refractory material that imitates the outermost refractory layer of the inner body, it was cast into a metal plate of 120 × 70 × 1.2 mm ^t via a water glass coating layer as described above. A sample of the castable refractory after heat treatment at 1200° C. was subjected to a load in the longitudinal direction using an Amsler tester, and the shear strength was measured until the two separated.

Table 1 shows the configuration and evaluation results of each example.

Examples 1 to 8 are examples based on No. 2 water glass.
In Example 1, No. 2 water glass alone was applied, and the coating workability was good, and the coating film was uniform, and the thickness of the coating film was about 1 to 2 mm. A bonding strength of 2.1 MPa was obtained, which was greatly improved compared to <0.1 in Comparative Example 1, which is a conventional technique having no adhesive layer.

Examples 2 to 8 are examples in which water glass No. 2 contains oxide refractory raw material particles. All of the oxide refractory raw material particles used had a size that could pass through a sieve with an opening of 0.212 mm.
In Examples 2 to 6, in which the content of the oxide refractory raw material particles was 10% by mass or less, the bonding strength was higher than when the oxide refractory raw material particles were not contained (Example 1), but the oxide refractory raw material particles When the content of the raw material particles exceeds 10% by mass (Examples 7 and 8), the coating workability (spreadability, etc.) on the metal plate begins to deteriorate, and unevenness occurs on the coated surface, which reduces the bonding strength. became a trend. For this reason, in Examples 7 and 8, confirmation (pull-out test) using an actual machine was not performed.

Examples 9 to 14 are based on No. 3 water glass. The tendency was the same as in Examples 1 to 8, which were based on No. 2 water glass.

In an actual machine, a gas blowing plug was attached to the tuyere using the above-mentioned refractory layer as a joint material. It was confirmed whether it could be removed together with the metal plate.
In Comparative Example 1, which is a prior art that does not have an adhesive layer, the refractory layer could not be pulled out together with the gas blowing plug (conceptually, see Fig. 3). Except for Examples 7, 8, 13, and 14, all of the examples were able to pull out the refractory layer together with the gas blowing plug (conceptually, see FIG. 2).

1 inner body 2 metal plate (metal case)
3 adhesive layer 4 dense refractory layer 5 sealing material 6 breathable refractory layer 7 gas introduction pipe 8 tuyere 9 joint material

Claims (6)

An inner body fitted and attached to a tuyere of a molten metal container, wherein at least a region of the outermost peripheral surface of the inner body that is in contact with the inner hole surface of the tuyere through a joint material is attached to the tuyere. It has a layer (hereinafter referred to as "adhesion layer") that has a function to adhere to the joint material after receiving heat from being attached and used , and the adhesion layer contains a silicate derived from water glass . interior body. The adhesive layer contains at least one type of refractory raw material particles of alumina, alumina-silica, zircon, spinel, or silicic acid with a particle size of 0.5 mm or less, or metal particles in total of 10 mass. % or less . The internal body according to claim 2 , wherein the metal particles are iron or iron-based alloy particles. The inner body according to any one of claims 1 to 3 , wherein the adhesive layer has a maximum thickness of 0.5 mm or more and 2 mm or less. 5. The method for manufacturing an inner body according to claim 1 , wherein an adhesive layer is formed on the outermost peripheral surface of the inner body with a material containing silicate derived from water glass , A method of manufacturing an inner body, comprising a step of heat-treating at 100° C. or higher after layer formation. The method for manufacturing an internal body according to claim 5 , wherein the water glass has a _SiO2 / _R2O (R: alkali metal) molar ratio of 2.35 or more and 3.35 or less.

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