JP2008094677A - Hot spray repair material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot spray repair material which is excellent in anti-exfoliation property and can be cured in a short time. <P>SOLUTION: In the hot spray repair material which contains a refractory raw material containing particles having particle sizes of ≤75 μm in an amount of 20-40 wt.% and a binder forming carbon bond under a hot condition, a metal powder or iron alloy powder containing iron (Fe) as a main component and particles having particle sizes of ≤1.0 mm in an amount of ≥70 wt.% is added in an amount of 5-50 wt.% to the total amount of the refractory raw material and the binder. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hot spray repair material applied to the furnace wall and the bottom of a steelmaking facility such as a converter, electric furnace, ladle, etc., and in particular, hot spray excellent in short-time curing and exfoliation resistance. Related to repair materials.

  In order to improve production efficiency, furnace repair time between the furnace walls and the bottom of steelmaking facilities such as converters, electric furnaces, ladles, etc., tends to be shortened, and the number of repairs is also suppressed, so high There is a need for durable repair materials. In converters and the like, shortening of the curing time after construction and improvement of peeling resistance have been demanded.

Conventionally, as a spray refractory composition (spray repair material) applied to furnace walls and bottoms of steelmaking equipment such as converters, electric furnaces, ladles, etc., refractory aggregates are inorganic such as phosphates or silicates. What added the binder in the ratio of 3 wt%-10 wt% is known.
However, as the operating conditions of the steelmaking furnace become severe, there is a problem that the durability is insufficient. This is presumably because the inorganic binder forms a low-melting-point material at the time of heat bonding, and the construction body is easily contracted and easily peeled off. In addition, since the melting point of the matrix is lowered, it is considered that it is easy to melt and cause a decrease in durability.

  Further, a so-called carbon bond spraying material to which pitch or phenol resin is added is also known, but the curing time until the binder pitch is baked is longer than that of the phosphoric acid bond spraying material. Moreover, since it is a carbon bond, it is inferior to the softness in hot, and cannot generate | occur | produce the distortion which generate | occur | produces in the rotary tilting furnace like a converter, and becomes a factor of peeling damage.

Moreover, a converter baking repair material to which iron powder is added is also introduced as a repair material to which metal powder is added (see Patent Document 1). The purpose of this is to lower the construction surface temperature and improve the adhesion by adding iron powder to the baking material. When the baking material powder is hot at room temperature, it is slurried by melting the pitch, the iron powder settles, and iron is unevenly distributed at the boundary with the construction surface at the bottom. It is said.
However, since iron is concentrated at the bonding interface, the molten steel is easily inserted into the interface between the construction body and the construction surface during the refining process, and the baking construction body is peeled off, so that sufficient durability cannot be obtained.

Japanese Patent Laid-Open No. 11-278948

  The carbon bond spray material has higher durability compared to the phosphate bond spray repair material, but a) has a long curing time, b) lacks hot softness and easily peels off against physical strain. There is a problem. That is, the carbon bond spray material is cured from the surface to be heated and the construction surface after being sprayed. However, the inside of the construction body is difficult to transmit heat, and the curing tends to be delayed. Further, once the carbon bond is formed, the strength in the hot state is high, but it is difficult to be deformed and is easily peeled off when stress is applied.

  This invention is made in view of the said problem, Comprising: It aims at providing the hot spray repair material which is excellent in peeling resistance with respect to steelmaking furnace operation, and can be hardened for a short time. .

  The hot spray repair material according to the present invention is a hot spray repair material containing a refractory raw material containing a particle size of 75 μm or less from 20 wt% to 40 wt% and a binder that forms a carbon bond hot, A metal or iron alloy containing iron (Fe) as a main component is added to the total amount of the refractory raw material and the binder in an amount of 5 wt% to 50 wt% (claim 1).

  Further, the hot spray repair material according to the present invention is a hot spray repair material comprising a refractory raw material containing a particle size of 75 μm or less from 20 wt% to 40 wt% and a binder that forms a carbon bond between the heat. The metal powder or iron alloy powder containing iron (Fe) as a main component and containing a particle size of 1.0 mm or less at 70 wt% or more is 5 wt% to 50 wt% with respect to the total amount of the refractory raw material and binder. It is characterized by being added (claim 2).

  The hot spray repair material according to the present invention includes a specific amount (5 wt% to 50 wt%) of “a metal mainly composed of iron” in a binder that forms a carbon bond between a refractory material (refractory aggregate) and heat. By adding “powder or iron alloy powder”, heat conductivity is increased and heat is easily transmitted to the inside of the construction body, so that the curing time can be shortened and the repair time can be shortened. In addition, since the metal network structure is formed, the hot deformability is increased, and the toughness at low temperature is increased, so that the effect of being difficult to peel occurs.

  Hereinafter, embodiments of the present invention will be described. Prior to that, the functions and effects produced by the present invention will be described in more detail in relation to the prior art.

As described above, the conventional carbon bond spraying material contains pitch and the like as a binder, and after being sprayed and adhered, the binder is melted by applying heat and then cured to form a carbon bond. Adhere firmly. The strength of the construction body after curing is sufficiently high. By containing carbon, it is difficult for slag to infiltrate and a highly durable construction body can be obtained.
However, if the curing time is not taken and sufficient heat is not transmitted to the inside, the durability is reduced due to lack of strength. In addition, carbon bonds are difficult to creep in the hot state, and are easily cracked when stress is applied. In a furnace that rotates during operation, such as a converter, stress may be applied due to strain or the like, and may be peeled off.

On the other hand, the hot spray repair material according to the present invention uniformly adds iron into the construction body by adding metal powder (or iron alloy powder) containing iron as a main component to the carbon bond spray material. The metal powder as a main component is dispersed, the thermal conductivity of the construction body can be increased, and the binder can be accelerated.
When heat is further applied, metal powder (or iron alloy powder) containing iron as a main component is fused together to form a network structure in the construction body. This metal network structure gives the construction body stress relaxation capability by imparting moderate hot softness at high temperatures during operation, and when the temperature falls, it has toughness to increase fracture strength, cracks and Makes peeling difficult. In this way, the metal powder (or iron alloy powder) containing iron as a main component is uniformly added into the construction body to form a metal network structure, thereby shortening the curing time that is a problem of the carbon bond spraying material. It is possible to improve peeling during the refining process.

In order to “uniformly disperse and form a network structure” of iron-based metal powder (or iron alloy powder), which is effective in reducing peeling resistance and hardening time,
a. It is necessary to carry out spray construction. If the metal is unevenly distributed as in the baking material described in Patent Document 1 (Japanese Patent Application Laid-Open No. 11-278948), improvement in the thermal conductivity of the entire construction body cannot be expected, and shortening of the curing time cannot be expected. With the spray construction method, the metal powder (or iron alloy powder) containing iron as a main component can be uniformly dispersed in the construction body, which improves the thermal conductivity of the construction body and burns it to the center. However, the effect which becomes quick compared with a normal carbon bond spraying material is acquired.
b. As for the particle size of the metal powder (or iron alloy powder) whose main component is iron to be added, 1.0 mm or less must be 70 wt% or more. This is because if the particles are coarser than 1.0 mm, they are likely to be unevenly distributed, and unless they are added in a large amount, the thermal conductivity is not improved and a network structure cannot be formed. Moreover, when the addition amount of this metal powder (or iron alloy powder) is also less than 5 wt%, thermal conductivity is not sufficient, and hardening of a binder does not progress easily to the inside of a construction body. For this reason, the central portion tends to be burnt. By adding 5 wt% or more, a short-term curing effect can be obtained. On the other hand, even if the addition amount is too large, the refractory structure is divided and the service life is reduced. Therefore, the addition amount of metal powder (or iron alloy powder) containing iron as a main component is 5 wt% to 50 wt% is preferable, More preferably, it is 10 wt%-30 wt%.
c. If the refractory raw material having a thickness of 75 μm or less is more than 40 wt%, the metal network structure is divided to hinder the effect. On the other hand, if the amount is less than 20 wt%, the metal ratio is too high, the construction body becomes too soft during the heat, and the durability is reduced.
d. Even if a metal network structure is made, the effect expected from oxidation cannot be obtained, so a binder that forms a carbon bond that has the effect of reducing iron-based metal powder (or iron alloy powder) is applied. There is a need to.

  As the refractory raw material in the present invention, commonly used refractory materials and refractory aggregates can be used. For example, fused alumina, sintered alumina, sintered mullite, calcia partially stabilized zirconia, yttria partially stabilized zirconia, chamotte, One kind of silicon carbide or the like can be used, and a mixture thereof can also be used. In particular, MgO, MgO—CaO aggregates adjusted to a particle size of 3 mm or less, such as electrofused magnesia, sintered magnesia. Basic aggregates such as clinker, natural magnesia clinker, natural dolomite clinker, synthetic dolomite clinker, MgO-C brick waste and dolomite brick waste are preferred.

  Examples of the “binder that forms a carbon bond with heat” in the present invention include resins and pitches. In particular, it is preferable to apply one or two or more of a resol type phenol resin, a phenol / formaldehyde resin, and a high softening point pitch (softening temperature: 100 ° C. to 500 ° C.). A combination of pitches having different softening point temperatures is preferable because the adhesion rate is improved by expanding the softening point range of the construction body. The added amount is preferably 2 wt% to 35 wt% as a total amount, and more preferably 8 wt% to 25 wt%.

  Metal powder or iron alloy powder containing iron as a main component is usually added for the purpose of preventing carbon bond oxidation or controlling the temperature of the construction surface as disclosed in JP-A-11-278948. By forming a three-dimensional network structure of metal or alloy in the interior, imparting softness at high temperature, improving fracture energy at low temperature, and improving the thermal conductivity of the construction body, curing immediately after spraying construction Since it is added for the purpose of shortening the time, the addition amount is larger than that for the purpose of preventing oxidation, and 5 wt% to 50 wt% is required as an outer shell. If it is 5 wt% or less, a network structure cannot be formed, while if it is 50 wt% or more, the durability of the construction body is lowered. In order to form a network structure and improve durability, a more preferable addition amount is 10 wt% to 30 wt%. As the type, in addition to iron powder, mill scale and the like can be used, and Fe-Si, Fe-Cr, Fe-Cu, Fe-C, Fe-Ni-Cr, Fe-Mn, Fe-Mn- Iron alloys such as Si, Fe-Ni, Fe-Al, Fe-Mo, Fe-V can be used.

  Examples of the metal powder or alloy powder include powders of aluminum, silicon, aluminum-magnesia alloy, ferrosilicon, iron, magnesia, etc. In the present invention, metal powder or iron alloy powder mainly containing iron is used. It is characterized by using. An iron-based material is effective because it can be added in large amounts in terms of price. If coarse particles containing 30 wt% or more of metal particles exceeding 1.0 mm are included, it is likely to be unevenly distributed in the sprayed construction body, and if not added in large quantities, the thermal conductivity cannot be improved and a network structure cannot be formed. What contains 70 wt% or more of the following is desirable.

  If the amount of metal powder or iron alloy powder containing iron as the main component is 5 wt% or less, a network structure cannot be formed, and sufficient toughness at low temperatures and softness at high temperatures cannot be exhibited. End up. In addition, sufficient thermal conductivity cannot be obtained. On the other hand, when it exceeds 50 wt%, it becomes too soft in the hot state, and the deterioration of the erosion resistance is greatly changed, leading to a decrease in the durability. In order to satisfy durability and improved thermal conductivity, the amount of metal powder or alloy powder added is 5 wt% to 50 wt%, preferably 5 wt% to 50 wt%, based on the total amount of the refractory raw material and the binder that forms a carbon bond between the heat. Is 10 wt% to 30 wt% of the outer covering.

  As described above, the “carbon bond hot spray repair material containing metal powder or iron alloy powder containing iron as a main component” according to the present invention is effective in suppressing the oxidation by the carbon bond binder, and appropriate for the refractory raw material and metal powder. By addition, the metal powder or iron alloy powder containing iron as a main component is uniformly dispersed and a network structure is formed between the hot layers, thereby providing unprecedented high peel resistance and short-time curing characteristics.

  In addition to these components, the hot spray repair material according to the present invention is added with a small amount of additives such as a peptizer, fibers, clay, silica flour and the like, as necessary.

  The peptizer is added as necessary to improve the compactness of the structure of the construction body. For example, inorganic peptizers such as sodium hexametaphosphate and sodium silicate, polyalkylallyl sulfonic acid soda, and polyacrylic are used. Examples thereof include organic peptizers such as acid salts, and are added at a rate of 0 wt% to 1 wt%, preferably 0.02 wt% to 0.5 wt% with respect to the refractory raw material.

  The fibers are added for the purpose of preventing dripping on the vertical wall of the sprayed slurry. Examples thereof include inorganic fibers such as alumina fibers and carbon fibers, natural fibers such as hemp, and organic fibers such as organic synthetic fibers. And added at a rate of 0 wt% to 0.2 wt%, preferably 0.01 wt% to 0.1 wt%, relative to the refractory raw material.

  Clay or silica flour is added in order to increase the plastic fluidity when the water immediately after spraying the spray material is not yet dry and to enhance the adhesion. Further, since a small amount of melt is generated in the hot state, it is also effective in suppressing metal oxidation. If this addition amount is 0.2 wt% or less, since the amount is small, neither the adhesive effect nor the melt effect can be expected. On the other hand, if it is 10 wt% or more, the amount of melt produced is too large, and it is easy to sinter and peel easily. Therefore, the addition amount of clay or silica flour is preferably 0.2 wt% to 10 wt%.

  The hot spray repair material according to the present invention, after adding water to the above-mentioned mixture of components, sprayed and applied to a furnace wall, a furnace bottom, etc. of a steelmaking facility by a conventional method, is then heat-cured.

Hereinafter, the hot spray repairing agent according to the present invention will be specifically described with reference to examples of the present invention together with comparative examples.
Table 1 shown below is “refractory material (refractory aggregate)” and “particle size” used in each example. The finest refractory material was ball milled material (see “Ball Milled” in Table 1). Table 2 shows “metal powder or alloy powder” and “particle size” used in each example.

(Examples 1-16, Comparative Examples 1-5)
Examples 1 to 8 and Comparative Examples 1 to 3 are shown in Table 3, and Examples 9 to 16 and Comparative Examples 4 and 5 are shown in Table 4.

Moreover, the following test was done about the hot spray repair agent obtained in each case, and the test result was written together in Table 3, Table 4.
(1300 ° C spray test)
In order to compare the durability in the laboratory, a spray test was conducted at 1300 ° C. hot. That is, 25 kg of material was put in a gun and sprayed with water in a 1300 ° C. kiln containing a spray panel. The adhesion rate at this time and the fire extinguishing time of the construction body were measured, and the crack conditions during cooling were also observed and displayed in Tables 3 and 4, respectively.
(Erosion test)
Corrosion resistance tests were performed using converter slag by the rotating drum method, and are displayed in Tables 3 and 4 as “corrosion resistance index”.

From Table 3, the following items could be confirmed.
Examples 1-8 are the result of examining the metal powder which uses Fe as a main component, and the fire-extinguishing time is improving remarkably with respect to the comparative example 1 which is not added. In Comparative Example 3 (addition of Al powder) in which Fe is not a main component, the metal (Al) is oxidized and a crack suppressing effect is not obtained. Similarly, Comparative Example 2 using a refractory aggregate containing a particle size of 75 μm or less and 16 wt% outside a predetermined range (20 to 40 wt%) does not have a crack suppressing effect. Examples 1, 5 to 8 show the effect of Fe addition amount.

From Table 4, the following items could be confirmed.
Examples 9 to 15 are "refractory aggregate type / addition amount", "resin type / addition amount", "pitch type / addition amount", "plasticizer type / addition amount", "peptizer type / addition amount", "fiber type".・ Although the “addition amount” is changed, cracks occur in all cases when a predetermined amount (specifically, 15 wt%) of “metal powder containing iron as a main component: specifically Fe powder” is added. Difficult and fire fighting time is short. Similarly, in Example 16 (iron alloy powder: specifically, an example in which Fe—Si powder is added), cracks are hardly generated and the fire extinguishing time is short.
On the other hand, Comparative Example 4 uses a metal powder that is easily oxidized (specifically, Si powder), and Comparative Example 5 has too much metal added (specifically, 60 wt% Fe powder). In addition, not only the crack suppression effect is not obtained, but also the corrosion resistance is lowered.

  The hot spray repairing agent according to the present invention has an effect of shortening the curing time and also has few cracks, so that the shortening of the repairing time and the durability improvement effect are recognized, and the applicability is extremely remarkable. is there.

Claims (2)

  In a hot spray repair material comprising a refractory raw material containing a particle size of 75 μm or less of 20 wt% to 40 wt% and a binder that forms a carbon bond hot, with respect to the total amount of the refractory raw material and the binder A hot spray repair material comprising 5 wt% to 50 wt% of a metal or iron alloy containing iron (Fe) as a main component.   In a hot spray repair material comprising a refractory raw material containing a particle size of 75 μm or less of 20 wt% to 40 wt% and a binder that forms a carbon bond hot, with respect to the total amount of the refractory raw material and the binder Hot spray repair characterized by adding 5 wt% to 50 wt% of metal powder or iron alloy powder containing iron (Fe) as a main component and containing 70 wt% or more of a particle size of 1.0 mm or less Wood.