JPS589887A - Sliding nozzle plate brick for molten metal flow rate control and manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention improves the durability of the product by constructing only the sliding part or the sliding surface part and the hole surrounding part of a plate brick for a sliding nozzle with a sprayed layer of refractory material formed by water plasma spraying. 41! ；、Sliding Tsuzu μ that has been made more affordable
The present invention relates to plate bricks for use in industrial use and methods for producing the same.

Currently, in order to control the flow rate of molten metal in molten copper, the sliping tsuzu μ method is widely used instead of the previous nozzle/stopper method.
Among the refractories that make up the refractories, the most important one is plate bricks, which usually consist of two to three pieces including a fixed plate and a sliding plate.

Conventional plate bricks for sliding nozzles of this type have been made by impregnating tar into fired bricks made of high-grade corundum, corundum-mullite, mullite, or zircon. Plate bricks are required to have excellent wear resistance against molten steel and ice resistance against molten steel and slag, and to slide smoothly without roughening the sliding surfaces. However, the above-mentioned types of fired bricks cannot satisfy all of the requirements such as wear resistance, corrosion resistance, and prevention of surface roughness at the same time, and eclectic materials are generally used.

For example, in the case of corundum-mullite, the corrosion resistance and wear resistance of molten steel improve as the amount of corundum increases, but on the other hand, K T
h (AA Ball resistance and peeling resistance decrease, resulting in surface roughness. Conversely, if there is a large amount of mullite, spalling resistance, peeling resistance,
Bearing properties are improved and surface roughness is reduced, but corrosion resistance and molten steel wear resistance are reduced. Therefore, it is generally said that a composition of around 50 to 80% corundum and 20 to 50% flute is good.

In recent years, alumina has been developed to compensate for the drawbacks of these fired products.
Carbon-based plate bricks have been developed and show durability superior to fired corundum-mullite bricks, but the performance is still biased depending on the composition, and K has not yet reached a level that satisfies all properties. As the ratio increases, the spall resistance improves, but the strength of the brick structure decreases. In addition to corundum, some mullite is also present in order to suppress the coefficient of thermal expansion of the bricks.

Currently, the general composition of this kind of company is 65% corundum, 25% mullite, and 10% carbon. iru.

In plate bricks for sliding tines, the parts of the brick that wear out are mainly around the holes and on the sliding surfaces. However, the plate bricks currently in use are generally made of the same material throughout, due to the manufacturing method.
As mentioned above, the material has to be eclectic in order to have several functions, and it is uneconomical as there are many wasteful parts.

In order to improve the durability around the hole of the plate brick,
A method of reinforcing the two-layer structure by inserting a ring made of refractory material such as Magne V or Zircon around the hole has been tested, but due to the difference in thermal expansion, the boundary between the sliding surfaces It is difficult to put it into practical use because it creates gaps, promotes surface roughness, and sometimes cracks.
Not yet reached.

In addition, in JP-A-55-158877, a refractory material having better corrosion resistance and wear resistance than the material of the base brick was applied to the inner surface of the hole and the sliding surface around the hole by a plasma method or an oxygen-acetylene method. We present a method for reinforcing the material by thermal spraying to a thickness of 10 mm or more and 10 mm or less. However, the specific method of thermal spraying is not disclosed, and when spraying the Company's refractory material □ to a thickness of 2118 or more using the thermal spraying technology at the time of filing, the thermal distortion of the sprayed layer due to oxygen-acetylene flame spraying is considerable. I need to hear about it.

Productivity is low and costs are extremely high. In addition, in the pouring method, the base material is 80-90% Al5Os A/4.
There is no particular mention of the material of the thermal sprayed material, and the technical idea behind it is understood to be that thermal spraying is used to reinforce conventional plate bricks, and the height of the plate brick itself is not mentioned. It is thought that it was aimed at lowering the quality and price, and the price was 1k%A.

The appropriate area for the thermal spraying area is 20 to 50 m5 outside the hole, but the problem of the difference in thermal expansion between the thermal spray layer and the base brick has not been sufficiently studied and solved, and the above-mentioned refractory ring fit Similar problems remain unsolved.

The object of the present invention is to improve the durability and reduce the price of a plate brick for sifting nozzles.

The present invention is a refractory made up of parts required to perform several different functions, and the purpose of this invention is to allocate only the necessary and sufficient materials to each part that meet the functions required, and to balance the safe. Kame no Oi is based on the technical idea of improving the function and durability of refractories and reducing their cost.

In the case of plate bricks for Sliding Tsuzu μ, corrosion resistance and wear resistance are poor in the area around the hole where it comes into contact with molten steel or slag, but surface roughness may occur in the sliding surface area.
In addition, other parts are required to have spalling resistance and maintain a certain degree of strength during use. It is.

As a result of various studies based on the background described above, we found that by adopting a method of forming a thermally sprayed layer of refractory material using a water plasma method, which has never been attempted in this field, it is possible to It was discovered that the above-mentioned performance required for a commercial play brick can be obtained extremely easily, and the present invention was completed.
Depending on the material of the base brick in the N plate brick k, the formation position of the sprayed layer by the water plasma method, and K, the following three types of ζ can be roughly classified. It is as follows.

(1) Refractory material is thermally sprayed on the sliding surface of the base material brick with high corrosion resistance and high wear resistance using water plasma method (Fig. 1) (2) High corrosion resistance and high wear resistance make up the area around the hole. After the wear-resistant bricks are fitted together, a refractory material is sprayed onto the sliding surfaces using a water plasma method (Fig. 2). And the structure of the plate brick of the present invention is as shown in Fig. 1 to
It can be roughly divided into □ things shown in Figure 3, and these □ will be explained in detail later.

In the present invention, a method of thermal spraying around the hole of a ν-F brick has also been studied, and its outline is illustrated in FIGS. 4 to 7.

As shown in Figures 1 to 6, the sliding surfaces of these plate bricks are coated with a refractory material by water plasma spraying.
1) Form (1). In the water plasma spraying method, an arc generated at 1mftK on the cathode and anode is stabilized with water (steam), and a refractory material is supplied into the generated high-temperature and high-velocity plasma flame, which melts and collides with the surface of the base material at high speed. In this method, the refractory material is firmly adhered to form a refractory skin. In the case of conventional gas plasma spraying, Ar is used as the working gas.
, He, fk, and other expensive gases, water plasma spraying uses less expensive water, and water plasma spraying allows for higher electrical output than gas plasma spraying, resulting in higher thermal spraying efficiency. The thermal spraying capacity is 10 times higher than that of conventional gas plasma spraying, and the thermal spraying cost has been reduced by approximately one-seventeenth. Plasma spraying of refractory materials was first made possible by the adoption of water plasma spraying.

Conventionally, plate bricks are molded and manufactured by blending several types of refractory materials with different coefficients of thermal expansion in particle size, so the difference in thermal expansion between the materials and between the aggregate and bond parts of the brick causes sliding problems. The roughness of the moving surface is exacerbated. In addition, the sliding surface of plate bricks is generally subjected to surface grinding, but when surface grinding bricks made of materials with different hardness, there is a limit to the grinding accuracy of the machined surface, and there is also a limit to Kljf machining efficiency. However, if the sliding surface is made of a flame-sprayed layer of refractory material, the structure will be uniform and very fine, which will prevent surface roughness due to differences in thermal expansion, etc., and improve the accuracy and efficiency of the grinding process. improves. The aforementioned Japanese Patent Application Publication No. 55-158877
In this method, the thermal spraying is limited to the area around the inner hole of the sliding surface, but in the present invention, the thermal spraying is applied to the entire sliding surface, which improves efficiency. Since the boundary between materials is exposed on the sliding surface, there is a risk of surface chafing or cracking caused by the difference in thermal expansion between different materials.
%/-h7 Another aim of the present invention is to actively utilize the sprayed refractory layer as a refractory itself, rather than as a reinforcement for the base brick.In the present invention, the sprayed layer of refractory material is Performed by plasma method. In water plasma spraying, conventional gas plasma spraying or oxygen
Thermal spraying capacity is greater than that of acetylene flame spraying, etc. (For example, in the case of alumina spraying, conventional gas plasma spraying
Its thermal spraying capacity is approximately 3 Ktt/'br, but water plasma spraying reaches approximately 60 Ill/hr).It is possible to form a Wivs thermal spray layer in a short period of time, thus increasing productivity.
It is also economically efficient. The idea of proactively using the sprayed layer itself as a refractory, which had not yet been invented, became possible for the first time with water plasma spraying.

Thermal spraying using the water plasma method is not limited to spraying onto the sliding surfaces as shown in Figures 1 and 2, but also around the molten metal passage holes (4) as shown in Figure 6. It is also possible to use low-grade base material bricks (3) for the base material bricks of plate bricks, which can be thermally sprayed. In other words, the base material brick that is to be in contact with molten steel must have corrosion resistance and abrasion resistance as long as it is stable against heat and stress. etc., sufficient durability can be obtained.

Figure 2 shows that only the periphery of the molten metal passage hole (4) is fitted with high-quality, highly corrosion-resistant and highly wear-resistant base material brick (2), and the rest uses low-grade base material brick (3). A sprayed layer (1,) is formed on the sliding surface part by a water plasma method, and in Figure 3, the base material of the plate bricks is all the above-mentioned low grade base material brick (3), and the sliding surface part and the base material (3) are formed. Hole (4)
Below 9, which is formed by continuously coating the peripheral parts of both the water plasma sprayed layers (1) and (6), the details of the base material brick and the sprayed layer formed by the water plasma method and the coating according to the present invention are shown. The details of the manufacturing method of plate bricks for sliding nozzles will be described.

The base material brick in Figure 1 and the brick that fits around the hole in Figure 2 are both highly corrosion resistant and highly wear resistant base material bricks (2).
In addition to corundum, corundum-mullite, mullite, zircon, alumina-carbonoxy, etc., which were conventionally used as plate bricks, there are also magnesia, spinel, magnesia-chromium, and alumina.
Chromium, zirconia, magnesia-carbon, spinel-carbon, zirconia-carbon 4#! The material may be silicon oxide, silicon nitride, sialonxy, or the like. Practically, it is preferable to use materials such as corundum-mullite, zircon, alumina-carbon, magnesia-carbon, and silicon nitride, which have excellent corrosion resistance, wear resistance, and spall resistance. .

Since the low-grade base material bricks shown in FIGS. 2 and 3 do not come into contact with molten copper or slag, they are not required to have corrosion resistance or wear resistance, and may be made of stone that can withstand heat and stress during use. Therefore, V
Refractory bricks with relatively low refractory properties such as yamot, forsterite, and cordierite, alumina-carbon bricks, magxia-carbon bricks made from low-grade raw materials, and carbon-based bricks such as some trout are alumina bricks. - Fireproof insulation bricks such as alumina-silica can be used as the base material brick. In particular, carbon-based bricks and refractory heat-insulating bricks are preferred from the standpoint of spall resistance.

Before thermal spraying, it is necessary to roughen the surface of the brick to be thermally sprayed by sandblasting, steel blasting, etc., and to thoroughly degrease, wash, and dry it.7Especially for carbon-based bricks. Since a binder such as resin is used in the manufacturing process, it is necessary to thoroughly caulk the material before thermal spraying.

Alumina (
(including those containing titania), magnesia, silica, diA/:Inia (including zirconia stabilized with c&0 or MgO), spinel, zircon, chromium oxide, as well as alumina-silica, alumina-chromium, Any oxide ceramics commonly used as raw materials for refractories, such as magnesia-chromium surfaces, and mixtures of two or more thereof can be used. Also, a mixture of oxide ceramics and metals and/or non-oxide ceramics such as expanded materials and aceritized materials can be used. In particular, from the viewpoint of corrosion resistance and wear resistance, alumina, zirconia, zircon, spinane, chromium oxide, and mixtures of two or more thereof are suitable. Adjust to appropriate particle size and use. Refractory materials are generally supplied with a pressurized gas, such as compressed air, into the plasma flame generated in a water plasma spray system. Refractory Materials Co., Ltd.In order to obtain good fluidity during transportation, it is necessary to dry the product sufficiently beforehand.

As mentioned above, in the water plasma spraying method, the arc generated between the cathode and anode is stabilized by water (steam), and a refractory material is supplied into the generated high-temperature, high-speed plasma flame, which is then melted and sprayed at high speed. It collides with the surface of the base material and firmly adheres to form a film. In the case of gas plasma spraying, expensive gases such as Ar and He are used as the working gas.
In contrast, water plasma spraying uses inexpensive water.

In addition, since the electrical output can be set higher in a water plasma flame than in gas plasma spraying, the spraying efficiency is higher and melts.

Therefore, the thermal spraying cost is about 1,717 yen compared to gas plasma.

The above refractory material is supplied to a water plasma spraying device and is sprayed onto the surface of the base brick to form a refractory reflection. This refractory structure has a uniform and extremely dense structure, resulting in a refractory that is far superior in physical properties and strength compared to ordinary refractory bricks. The thickness of the sprayed coating is 3 to 30 cm, preferably 5 to 15 wI.
It's k. If the thickness of the sprayed coating is less than 3K, the thickness of the sprayed layer will become even thinner due to the later surface grinding process, so it is dangerous to expect sufficient durability.If it is 30111 or more, the spall resistance will decrease and the plate The sprayed layer occupies a large proportion of the entire brick, making it rather uneconomical.

In thermal spraying, it is generally better to spray from a direction perpendicular to the surface to be sprayed, as the properties of the sprayed layer and its adhesion to the base material are better. It is difficult. Therefore, the methods shown in FIGS. 4 to 7 are suitable for spraying the area around the passage hole (4) shown in FIG. 3.

The method shown in Figure 4 involves preparing a base material brick that has a tapered shape with fine steps around the hole, and using a brick as a diameter patch plate because the adhesive strength of the sprayed layer (1') is weak and it can be easily peeled off. It is also possible to use a carbon plate (for example, a carbon plate).

□After spraying, use materials that can be removed by melting by heating or dissolving with a solvent, or materials that can be removed by grinding, such as bricks. Thermal spraying is carried out continuously from the periphery of the hole to the sliding surface, and then after the cover plate is removed, the holes are drilled and the sliding surface is ground to form a plate brick.

In the method shown in Fig. 5, a core (6) is made of the same material as the cover plate used in the method shown in Fig. After thermal spraying, the core (6) is removed. According to this method, the amount of refractory material can be reduced compared to the method shown in FIG. 4, and the drilling step can be omitted.

The method shown in Fig. 6 is to spray a base material brick with tapered holes from the direction of the tapered m angle while rotating, then spray the sliding surface, and then perform drilling and grinding. The method shown in Fig. 7, which is to obtain the desired play Y brick, is to perform thermal spraying from the hole Mal using the method shown in Figs. 6 and ^.

By using the ζO method, the area around the hole is made up of a thermally sprayed layer (f) to form the desired plate brick.

In particular, the method presented in Figs. 4 to 7 Ilc is well adapted to the damage pattern of plate bricks,
This is very preferable because the parts that are easily damaged can be constructed with a flame-sprayed layer of corrosion-resistant and highly wear-resistant refractory material. Furthermore, the inventors have found that spraying the refractory material onto the refractory base material at high temperatures improves the properties of the sprayed coating and its adhesion to the base material. If the base material is not a metal but a large material, it is possible to heat it to a considerably high temperature K, and as the temperature increases, the properties of the sprayed coating and the adhesion of the base material bricks are significantly improved. This hot spraying method can also be applied to the plate bricks of the present invention.7 In other words, the base material brick is set in a heating furnace such as an S1C resistance furnace, heated to a temperature of 80°C or higher, and placed on the wall of the heating furnace. After spraying a window, it is left to cool or slowly cool. By performing hot thermal spraying, it is possible to not only improve the physical properties and adhesion of the sprayed coating, but also to remove the distortion that occurs in the sprayed coating during the cooling process by air cooling or slow cooling.At temperatures around room temperature. In thermal spraying, it is difficult to form a thick thermal spray coating because thermal stress distortion occurs due to local overheating and rapid cooling of the sprayed area, which causes peeling.7For example,
When alumina is thermally sprayed at a temperature around room temperature, the thermal sprayed coating is likely to be composed of a considerable amount of T-Al, O, etc., which not only deteriorates the physical properties and strength of the thermal sprayed coating, but also deteriorates the properties of the thermal sprayed coating during use as plate bricks. When heated, alumina #1 transforms into -Alρ8 and changes in volume, causing problems such as a change in volume, and when thermally sprayed at temperatures above 80°C, almost all of the alumina #1 forming the sprayed coating becomes type A. The once fired bricks may be heated again in a heating furnace and then hammered, but this can also be done during the brick firing process. In order to prevent oxidation of carbon when hot spraying is carried out on bricks containing Naori-bon, it is necessary to maintain a non-oxidizing atmosphere in the furnace.

The plate brick of the present invention is made by thermally spraying a refractory material on the sliding surface and around the hole using the water plasma method, and then perforated in the same way as the conventional plate brick (no perforation is required with the method shown in Figure 85).
and grinding to produce a product. In addition, by impregnating with tar, resin, etc. after thermal spraying, it is possible to make the pores have a cooking element.7 The plate brick of the present invention is made of highly corrosion-resistant and highly wear-resistant material for the parts that come into contact with molten steel and slag. The sliding surface is made of a uniform and dense flame-sprayed layer of refractory material, and surface roughness is significantly reduced, resulting in superior durability compared to conventional plate bricks.

Furthermore, by using low-grade carbon-containing bricks or heat-insulating bricks as the base material bricks, lower costs and weight can be easily achieved.

Examples of grate bricks according to the present invention are shown below.

Example 1 A corundum mullite fired brick was used as a highly corrosion-resistant and highly corrosion-resistant base material brick (2), and this was heated in a
Heat to 200℃ and apply particle size of 5.6 to 105μ on the sliding surface.
After heat spraying 111-7' of fused alumina powder to a thickness of 111-7' by direct water plasma spraying, it was left to cool in a furnace. After cooling to room temperature, tar impregnation treatment,
, perforation and grinding of the sliding surface, thermal spraying, layer (1)
A plate brick shown in FIG. 1 was prepared. The thickness of the sprayed layer (1) after the grinding process was 8 thick. 4 Example 2 A high alumina insulating brick is used as the base material brick (3), and after a highly corrosion resistant base material brick C2) made of an alumina fired brick containing chromium oxide is fitted to this, the sliding surface part is A 44 to 88 μm fused spinel powder was sprayed to a thickness of 5 cm from a water plasma sprayed layer at room temperature.

After the thermal spraying was completed, drilling, sliding, and surface grinding were performed to create the plate brick shown in Figure 2.The thickness of the thermal sprayed layer (1) after the grinding process was 13.5 m.

Example 6 A base material brick (3) made of alumina-carbon bricks according to the method shown in FIG. Sprayed below.

Thereafter, tar impregnation, caulking, perforation, and grinding of the sliding surface were carried out to produce the plate brick shown in FIG. 3. The thickness of the sprayed layer (1) on the sliding surface of this brick is 7
w*, the thickness of the sprayed layer (1) around the hole was 5 m at the thinnest point i.

The quality of the plate bricks of each example is shown in Table 1 in comparison with the quality of conventional plate bricks.

Notes (11 to (4)) in Table 1 are as follows.Note 7 (
1) The base material brick used in Example 1 is the same material as the brick of Comparative Example 1.

Note (2) Corrosion resistance index and d Cab/Sing = 3
．． ! -11600℃ for slug and gun with 22% Fe content
The corrosion resistance index of Comparative Example 1 is set to 10, which is the ratio of the reciprocal of the amount of corrosion when a slag test is performed.

Cut out a cylindrical sample of 2 and 1 on the circular sample surface at room temperature.
It is the ratio of the reciprocal of the amount of wear when polished with carborundum (#320) for a certain period of time under a load of 1.0, and the wear resistance index of the brick of Comparative Example 1 is set to 1.0.

Note (4) The small sliding nozzle device for testing is installed at the bottom of the induction heating furnace, and is a miniature model imitating the actual sliding nozzle μ device, 100 x 15
0 x 50 ms plate brick (hole W2Om1)
The discharge flow rate of molten steel in the induction heating furnace can be controlled by setting two pieces and sliding the lower plate bricks. In this test, SS4 of 1011f [After melting the steel and setting the molten steel temperature to 1600℃, the process of fully opening the sliding nozzle and discharging the molten steel is counted as one time, and the lower plate brick is slid 50% from the fully open state. The number of times until the molten steel did not stop completely even when the steel was moved or until the sliding resistance increased and sliding became impossible was determined.

As is clear from the comparison between the above examples and comparative examples, plate bricks with a refractory sprayed layer formed by the water plasma method are suitable for use as plate bricks for sliding nozzles due to the appropriate selection of refractory materials and their fine structure. It was confirmed that the durability was significantly improved compared to conventional products.

[Brief explanation of drawings]

1 to 3 are longitudinal sectional views of a plate brick for a sliding nozzle according to the present invention, and FIGS. 4 to 7 are longitudinal sectional views showing a procedure for thermal spraying around a hole in the plate brick. (l) (15 Refractory sprayed layer (2) Highly corrosion-resistant and highly wear-resistant refractory brick (3) Low-grade base material brick (4) Molten metal passage hole (5) Cover plate (6) Core (7)
) Thermal spray nozzle Applicant Kyushu Refractory Brick Co., Ltd. Agent Patent attorney Hiromibe Mori 5 Figure

Claims (1)

[Scope of Claims] 1. A slide plate for controlling the flow rate of molten metal, which is made by forming a thermally sprayed layer of a refractory material on the sliding surface of a base brick having passage holes for molten metal by the water-one-Tsuma method. Hmm. 2. The base material brick is a brick with high corrosion resistance and high wear resistance. The sliding nozzle for controlling the flow rate of molten metal according to claim 1 is a brick. 3. The base material brick is a low-grade brick, and the molten metal V-) A brick for a sliding nozzle for controlling the flow rate of molten metal according to claim 1, wherein only the peripheral portion of the passage hole is made of highly corrosion-resistant and highly wear-resistant brick. No. The area around the molten metal passage hole is a sprayed layer of refractory material made by water plasma method that is continuous with the sprayed layer on the sliding surface.
The plate brick of Sliping Tsuz N for controlling the flow rate of molten metal according to claim 1, wherein the other base material bricks are of low grade or of high corrosion resistance and high wear resistance. A highly corrosion-resistant, highly wear-resistant refractory material is applied to the sliding surface and the tapered hole surface of the base brick, which has a tapered hole that is larger than the SSS gold metal passage hole and expands over the sliding surface, using water plasma. The molten metal is coated by thermal spraying by a method to form a thermal sprayed layer around the passage hole and a thermal sprayed layer on the sliding surface continuous thereto, and the passage hole is formed by drilling or by drawing out a core. A method of manufacturing a play F brick for a sliding nozzle for flow rate control. 6. The method for manufacturing plate bricks with a sliding nozzle for controlling the flow rate of molten metal according to claim 5, wherein thermal spraying by the water plasma method is carried out at a temperature of 800° C. or higher on the bricks to be thermally sprayed.