JP2008120635A - Hot spray repair material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot spray repair material which is excellent in rapid drying property. <P>SOLUTION: In a binder-free hot spray repair material which contains a refractory raw material having grain sizes of ≤75 μm in an amount of 25-50 wt.% and forms a carbon bond under a hot condition, the hot spray repair material is obtained by adding a metal powder or an iron alloy powder, which contains iron as a main component and ≥70 wt.% powder fraction having particle sizes of ≤1.0 mm, to the refractory raw material in an amount of 5-50 wt.%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a hot spray repair material applied to furnace walls and bottoms of steelmaking equipment such as converters, electric furnaces, ladles, and RHs (hot containing no binder that forms carbon bonds hot In particular, the present invention relates to a hot spray repair material having excellent quick-drying properties.

  In order to improve production efficiency, the time required for repairing hot steel furnaces such as converters, electric furnaces, ladles, and RHs tends to be shortened, and quick-drying spray materials are required so that operations can be restored in a short time. It has been. If the molten steel is touched before the sprayed body is dried, the water explosively evaporates and the molten steel is scattered, which is dangerous.

  By the way, in the repair of the RH dip tube, a phosphoric acid and silicate bond type spraying material in which an inorganic binder such as phosphate or silicate is added to the refractory aggregate at a ratio of 3 wt% to 10 wt% is known. However, if it is repaired with repeated spraying, it takes time to dry. As measures against this, the inventors added fibers for improving air permeability and tried to use a binder that hardly gelled, but none of them achieved the effect of shortening the drying time.

  On the other hand, 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 and silicate bond spraying material. , Has the disadvantage of generating smoke. Therefore, unless the steelmaking equipment is equipped with a sufficient amount of heat and a dust collector, it is difficult to apply the carbon bond spray material, such as ladle slag line parts, RH immersion pipes, It cannot be applied under conditions where it is easy to cool at low temperatures.

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 phosphoric acid and silicic acid bond spray material is faster in curing than the carbon bond spray material and is suitable for repair during operation. However, in order to further shorten the repair time, it is important to shorten the time for drying the moisture of the construction body. Under conditions such as ladle slag line, RH dip tube, and electric furnace that has been allowed to cool, it is easy to cool down at a relatively low temperature.

  This invention is made in view of the said problem, Comprising: It aims at provision of the hot spray repair material which was able to repair for a short time with respect to steelmaking furnace operation, especially excellent in quick-drying property. .

  The hot spray repair material according to the present invention is a hot spray repair material containing 25 wt% to 50 wt% of a refractory raw material having a particle size of 75 μm or less and not including a binder that forms a carbon bond hot. A metal or iron alloy containing Fe) as a main component is added to the refractory raw material in an amount of 5 wt% to 50 wt% (Claim 1).

  Moreover, the hot spray repair material according to the present invention contains a refractory raw material having a particle size of 75 μm or less in an amount of 25 wt to 50 wt%, and does not contain a binder that forms a carbon bond hot, 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 is added to the refractory raw material. (Claim 2).

  Furthermore, the hot spray repair material according to the present invention is characterized in that the binder is silicate or phosphate.

  The hot spray repair material according to the present invention increases the thermal conductivity by adding a metal (metal powder) or iron alloy (iron alloy powder) containing iron as a main component, so that heat is easily transmitted to the inside of the construction body. As a result, drying of the construction body can be accelerated and repair time can be shortened.

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

Carbon bond spray material containing carbon contains pitch as a binder, and after being sprayed and adhered, the binder melts when heated, and then hardens to form a carbon bond that adheres firmly . The construction body also has a sufficiently high strength after being hardened, and the inclusion of carbon makes it difficult for slag to infiltrate, so that a highly durable construction body can be obtained.
However, since it requires heat to melt and solidify the pitch and generate harmful gas, it is difficult to apply it in a furnace without dust collection equipment, and the ladle slag line part, RH dip pipe, Under conditions that are easy to cool at a relatively low temperature, such as a cold electric furnace, solidification does not occur, and sufficient durability and shortening of repair time cannot be expected.

On the other hand, phosphoric acid and silicic acid bonds that do not contain carbon bonds adhere instantaneously by gelation, and moisture evaporates and solidifies. Although the repair time is shorter than that of carbon bond spray material, phosphoric acid and silicic acid bond spray materials are used in conditions that are easy to cool at relatively low temperatures, such as ladle slag lines, RH dip tubes, and cooled electric furnaces. However, further time reduction is required.
In addition, when the construction thickness is increased, the construction surface is hot, but since the thermal conductivity of the spray material is low, the heat is not easily transmitted to the surface, and drying is delayed.

  In order to shorten the repair time of these spraying materials even in conditions that are easy to cool at relatively low temperatures, such as ladle slag line parts, RH dip tubes, and electric furnaces that have been allowed to cool, pitches that take time to solidify, etc. It is important to use phosphoric acid and silicic acid bonds without using carbon bonds, and to improve the thermal conductivity of the construction body so that the drying proceeds smoothly even if the construction thickness is large. is there.

  In order to improve the thermal conductivity, it is effective to add metal powder or alloy powder containing iron as a main component. By spraying, metal powder or alloy powder containing iron as a main component is uniformly dispersed in the construction body, improving the thermal conductivity of the entire construction body, performing repeated spraying, and heat from the back even if the construction thickness is thick By transferring quickly, drying of the entire construction proceeds, so that drying is much faster and repair time can be shortened compared to ordinary phosphoric acid and silicic acid bond spray materials.

  Even if the metal powder is added, if the iron powder is unevenly distributed as in the baking method of Patent Document 1 (Japanese Patent Laid-Open No. 11-278948), the improvement in the thermal conductivity of the entire construction body cannot be expected. Although shortening of repair time cannot be expected, according to the hot spray repair material according to the present invention, since it is spraying construction, it is possible to uniformly disperse the metal or alloy mainly composed of iron in the construction body. Therefore, the thermal conductivity of the construction body is improved, and the entire construction body is heated uniformly.

  Hereinafter, the embodiment of the present invention will be described. As described above, the hot spray repair material according to the present invention contains a refractory raw material having a particle size of 75 μm or less in an amount of 25 wt to 50 wt%, and forms a carbon bond in the hot state. The hot spray repair material that does not contain the binder is characterized in that 5 wt% to 50 wt% of a metal or iron alloy containing iron as a main component is added to the refractory raw material.

  In the present invention, it is desirable that the metal or iron alloy containing iron to be added as a main component has a particle size of 1.0 mm or less and 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 large quantities, the thermal conductivity is not improved.

  Moreover, when the addition amount of the metal or iron alloy containing iron as a main component is less than 5 wt%, the thermal conductivity is not sufficient, and drying and solidification do not easily proceed to the inside of the construction body. For this reason, the central portion is likely to be in a state where moisture remains, and is dangerous because it explodes when touched with molten steel and the molten steel is scattered. By adding 5 wt% or more, the thermal conductivity is improved, and the effect of shortening the repair time 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 the metal or iron alloy containing iron as a main component is preferably 5 wt% to 50 wt%.

  In this invention, when there are too many refractory raw materials which have a particle size of 75 micrometers or less than 50 wt%, the heat-transfer effect of the said metal powder or iron alloy powder will be inhibited. On the other hand, if the amount is less than 25 wt%, the ratio of the metal powder or iron alloy powder is too high, and the construction body becomes too soft when hot, resulting in a decrease in durability.

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

  In the present invention, examples of the binder containing no carbon bond include phosphoric acid and silicic acid. In particular, it is preferable to apply one or more of sodium phosphate and sodium silicate in combination. As addition amount, 2 wt%-15 wt% are preferable as a total amount, More preferably, they are 5 wt%-10 wt%.

  Metal powder or alloy powder containing iron as a main component is usually added for the purpose of preventing carbon bond oxidation or suppressing the temperature of the construction surface, as described in Patent Document 1 (Japanese Patent Laid-Open No. 11-278948). However, in the present invention, it is added for the purpose of shortening the drying time of the sprayed construction body by improving the thermal conductivity of the construction body. %Is required. If it is 5 wt% or less, there is no sufficient effect of improving thermal conductivity, and if it is 50 wt% or more, the durability of the construction body is lowered. Furthermore, an addition amount of 15 to 35 wt% is preferable in order to uniformly disperse and improve thermal conductivity and not to reduce the durability.

  As a kind of metal powder or alloy powder containing iron as a main component, in addition to iron powder, mill scale, Fe-Si, Fe-C, Fe-Cr, Fe-Cu, Fe-Ni, Fe-Co, Fe- Examples thereof include powders such as Mn and Fe-Al. In particular, iron as a main component is effective because a large amount can be added in terms of price. When coarse particles of 30 wt% or more of metal particles or alloy powder exceeding 1.0 mm are included, it tends to be unevenly distributed in the sprayed construction body, and thermal conductivity is not improved unless added in large quantities. Therefore, 1.0 mm or less is 70 wt%. Those including the above are desirable.

  Thus, the phosphoric acid and silicic acid bond hot spray repair material containing the metal powder or iron alloy powder containing iron as the main component of the present invention is heat generated by uniform dispersion of the metal powder or iron alloy powder containing iron as the main component. The improvement in conductivity makes it possible to shorten the repair time that has never been seen before.

  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 in order to improve the compactness of the construction body structure. For example, inorganic peptizers such as sodium hexametaphosphate and sodium silicate, and polyalkylallyl sulfonate sodium, Examples include organic peptizers such as polyacrylates, and are added at a ratio of 0 wt% to 1 wt%, preferably 0.02 wt% to 0.5 wt% with respect to the refractory raw material (refractory aggregate). .

  The fibers are added for the purpose of preventing sagging at the vertical wall, and include, for example, inorganic fibers such as alumina fibers and carbon fibers, natural fibers such as hemp, and organic fibers such as organic synthetic fibers. It is added in a proportion of 0 wt% to 0.2 wt%, preferably 0.01 wt% to 0.1 wt%, with respect to the refractory material (refractory aggregate).

  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 the addition amount is less than 0.2 wt%, the amount is small, so that neither the adhesive effect nor the melt effect can be expected. On the other hand, if it exceeds 10 wt%, 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 is heated and hardened after water is added to the above-mentioned mixture of components and sprayed onto the furnace wall, furnace bottom, etc. of the steelmaking facility by a conventional method.
The amount of water added is preferably 10 wt% to 30 wt% on the outside. If it is less than 10 wt%, the fluidity after spraying is insufficient. On the other hand, if it exceeds 30 wt%, quick drying is impaired, which is not preferable.

Examples of the present invention will be described below together with comparative examples, and the hot spray repair material according to the present invention will be specifically described.
Table 1 to be displayed next is “refractory raw material (refractory aggregate) and its 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 thereof” used in each example.

(Examples 1-16, Comparative Examples 1-4)
Examples 1 to 8 and Comparative Examples 1 to 3 are shown in Table 3, and Examples 9 to 16 and Comparative Example 4 are shown in Table 4. Moreover, the following test was done about the hot spray repair material obtained in each case, and the test result was written together in Table 3, Table 4.

(Blowing test at 800 ° C)
In order to compare the durability in the laboratory, a spray test was conducted at 800 ° C. hot. That is, 25 kg of material was put in a gun, water was added at 16 wt% on the outside, and sprayed on a spray panel heated to 800 ° C. The adhesion rate and the drying time of the construction body at this time were measured, and the cracks during cooling were also observed, and these were displayed in Tables 3 and 4.
(Erosion test)
Samples of each example were collected and subjected to a corrosion resistance test using a converter slag by the rotating drum method, and displayed as “corrosion resistance index” in Tables 3 and 4.

From Tables 3 and 4 above, the following matters were confirmed.
Examples 1-16 are the result of examining the metal powder or iron alloy powder which has iron as a main component, Compared with the comparative example 3 which has not added this metal powder and iron alloy powder, drying time is marked. It has improved. Moreover, in the comparative example 4 (the example which added Al; -1.5mm) which does not use the metal powder and iron alloy powder which have iron as a main component, oxidation of a metal (Al) advances and the drying promotion effect is not acquired. . In addition, cracks were observed during cooling.

Examples 1, 5 to 8 show the effect of Fe addition amount. In Examples 9 to 15, "refractory raw material type / addition amount", "binder type / addition amount", "plasticizer type / addition amount", "peptizer type / addition amount", "fiber type / addition amount" However, the drying time is short in all cases due to the addition of metal powder or iron alloy powder containing iron as a main component. Similarly, Example 16 (an example in which Fe-Cr iron alloy powder was added) has a short drying time.
On the other hand, Comparative Example 1 (an example in which the binder is a pitch and contains a binder that forms a carbon bond in the hot state) is not cured because the drying time and the curing time are delayed. Further, in Comparative Example 2 (an example in which a refractory raw material (refractory aggregate) having a particle size of 75 μm or less is included in the range (25 to 50 wt%) specified by the present invention “16 wt%”), the refractory aggregate fine powder is There are too few metal ratios, and corrosion resistance has fallen.

The hot spray repair material according to the present invention increases the thermal conductivity by adding a metal (metal powder) or iron alloy (iron alloy powder) containing iron as a main component, and heat is transmitted to the inside of the construction body. It becomes easy to accelerate the drying of the construction body, enabling unprecedented “reduction of repair time”, and its applicability is extremely remarkable.

Claims (3)

  In a hot spray repair material containing 25 to 50 wt% of a refractory raw material having a particle size of 75 μm or less and containing no binder that forms a carbon bond in the hot state, a metal or iron alloy containing iron (Fe) as a main component A hot spray repair material comprising 5 wt% to 50 wt% added to the refractory raw material.   A hot spray repair material that contains 25 wt% to 50 wt% of a refractory raw material having a particle size of 75 μm or less and does not contain a binder that forms a carbon bond in the hot, iron (Fe) as the main component, and 1.0 mm A hot spray repair material obtained by adding 5 wt% to 50 wt% of metal powder or iron alloy powder containing 70 wt% or more of the following particle size to the refractory raw material. The hot spray repair material according to claim 1 or 2, wherein the binder is silicate or phosphate.