JPH0324212A - Tilting spout - Google Patents

Abstract

PURPOSE:To improve the resistance of the tilting spout to infiltration, corrosion and thermal spalling and to prolong the service life thereof by forming a refractory member having a molten metal passage, etc., of a metal-impregnated refractory molding. CONSTITUTION:This tilting spout 1 is formed of a molten metal contact part 4 which receives the molten metal, the refractory member 3 having the molten metal passage 5 branched therefrom, a supporting member which oscillatably supports the refractory member, etc. The above-mentioned refractory member 3 is formed of the metal-impregnated refractory molding formed by impregnating 10 to 70wt.% metal in the porous body of castable refractories.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a tilting gutter.

[Prior Art] Blast furnace hot metal is tapped through a plurality of blast furnace main troughs. The blast furnace main trough has a slag trough in the middle, and removes slag other than the necessary amount covering the slag. A tilting trough is arranged below the downstream end of the blast furnace main trough to distribute the melt into the ladle.

This tilting gutter has a hot water contact part and a plurality of molten metal passages branching from the hot water contact part, and is supported as a whole so as to be swingable. The slag (including the necessary amount of slag) that has fallen from the end of the blast furnace main trough is received by the hot water contact part, and the sludge is distributed into the pot by tilting the entire trough to one side.

As mentioned above, this tilting gutter is a melt distribution device, so it requires mechanical performance. Not only is this required, but direct contact with hot hot metal and chemically active slag can cause various types of damage. For this reason, various strict properties are required of the molded refractory material used to form the pouring trough.

First, it is necessary to have a property (hereinafter referred to as infiltration resistance) that prevents hot metal and slag (hereinafter referred to as slag etc.) from infiltrating into the pores of the refractory molded body.

This is because when slag etc. infiltrates into the pores of the refractory molded body, chemical abrasion of the refractory bricks, that is, erosion and erosion, occurs, and accompanying this, structural spalling occurs.
This is because the refractory molded body will be damaged. For this reason, the properties required of a refractory molded article for tilting troughs include infiltration resistance, erosion resistance, and structural spalling resistance.

Moreover, the refractory molded body for the tilting gutter needs to have stability against rapid heating caused by molten steel. That is, it is necessary to prevent thermal spalling caused by thermal stress caused by rapid heating. Therefore, the second property required of a refractory molded article for a tilting trough is heat resistance and spalling properties.

Furthermore, the tilting trough is subjected to severe physical wear at the temporary part because it is directly hit by the molten steel flow falling from the blast furnace main trough. If the abrasion of the contact area becomes severe, it will have a significant impact on the smelt distribution work, and the entire ironmaking operation will be disrupted.

Therefore, wear resistance is required as a third property.

Conventionally, tilting molded refractories for tilting troughs have been used in which alumina/silicon carbide/graphite monolithic refractories or alumina/silica monolithic refractories are poured into iron molds and formed.

[Problem to be solved by the invention] However, in alumina/silicon carbide/graphite monolithic refractories, when slag etc. infiltrate the pores, the carbon contained therein is oxidized and the refractory molded body itself deteriorates. , secondary erosion, structural spalling, and thermal spalling were disadvantageous. Furthermore, since the refractory molded body deteriorates and the refractory strength is extremely reduced, there is a drawback that the abrasion resistance is also poor.

Further, since the alumina-siliceous refractory molded body is also porous, it is impossible to prevent the infiltration of slag and the like, and it is virtually impossible to suppress erosion and structural spalling caused by this. Moreover, the heat-resistant spalling property was still not fully satisfactory.

Generally, as a measure to prevent the infiltration of slag and the like, refractories are made denser. However, when refractories are densified to improve infiltration resistance and erosion resistance, there is a drawback in that heat-resistant spalling decreases.

As described above, it is difficult to improve both erosion resistance and thermal spalling resistance, and it has been desired to develop a tilting gutter that has both properties.

Furthermore, it has been desired to develop a tilting trough that has excellent abrasion resistance against physical abrasion caused by molten steel flow.

The present invention has been made in view of the above circumstances, and provides a gutter with excellent infiltration resistance, erosion resistance, structural spalling resistance, thermal spalling resistance, and abrasion resistance. The purpose is to

[Means for Solving the Problems] An object of the present invention is to provide a fireproof member for forming a contact portion for receiving molten metal and a plurality of molten metal passages branching from the contact portion, and a fireproof member that swingably supports the fireproof member. and a support member;
The refractory member includes a metal in an amorphous refractory porous body of 10 to 7
This is accomplished by means of a tilting trough, which is characterized by a metal-impregnated refractory molded body impregnated with a proportion of 0% by weight.

[Function] The fireproof member of the tilting gutter of the present invention is formed of a metal-impregnated monolithic refractory molded body in which the pores of the monolithic refractory molded body are impregnated with metal. By impregnating the pores of the amorphous refractory molded body with metal, its apparent porosity becomes smaller than that of ordinary refractory bricks and the like. That is, since the pores of the monolithic refractory molded body are filled with metal, it is difficult for slag etc. to enter the monolithic refractory molded body.
Improves penetration resistance. As the infiltration resistance improves, the erosion resistance and structural spalling resistance also improve.

In addition, since erosion caused by slag and the like is small, the strength of the refractory is less reduced and wear resistance is improved.

Furthermore, by impregnating Kinkutsu, the thermal conductivity of the tilting gutter is improved and heat dispersibility is improved, making it difficult for thermal stress to occur.
Heat-resistant spalling properties are also improved.

[Examples] Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1a is a perspective view showing a tilting trough according to an embodiment of the present invention, and FIG. 1b is a front view showing a tilting trough according to an embodiment of the invention. The tilting gutter 1 is covered with an iron skin 2 on the outside, and a fireproof member 3 is arranged inside the iron skin 2. This refractory member 3 has a stop portion 4 and a plurality of molten metal passages 5 formed therein. A support member 6 is sunk into the iron skin 2 at the bottom of the tilting gutter 1. This supporting RF member 6 is connected or integrated with a swinging device (not shown), and the tilting gutter can be swinged by the operation of this swinging device to distribute the melt.

Further, according to FIG. 1b, the support member 6 is fixed to a metal plate 7, and this metal plate 7 is provided with supports 8a and 8b to prevent the tilting gutter 1 from swinging too much. There is.

Next, the fireproof member 3 will be explained in detail.

In the present invention, the refractory member 3 is formed of a metal-impregnated monolithic refractory or shaped body.

As mentioned above, a metal-impregnated monolithic refractory body is a monolithic refractory body whose pores are impregnated with metal. A monolithic refractory molded product is produced by mixing refractory raw materials and additives such as a binder and charging the mixture into a mold.
It is baked at a temperature of ℃. The refractory raw material may be of any material, such as high alumina, alumina/carbon, chamotte, alumina/silica, magnesia, magnesia◆carbon, and alumina/carbon.
Silicon carbide, graphite, etc. can be used.

In addition, the metals to be impregnated include nickel, stainless steel, iron,
It can be any metal, such as chromium.

Further, the metal can be impregnated alone or in combination with a plurality of metals.

The amount of metal impregnation is approximately 10 to 10% of the weight of the refractory brick, etc.
It is appropriately selected within the range of 70% by weight so as to obtain the desired effect. The lower limit of gold 1714 a immersion amount is approximately 10% by weight.
The reason for this limitation is that in order to obtain a sufficient heat-resistant spalling effect as a tilting trough, it is necessary to impregnate the metal in an amount of 10% by weight or more. Also, the upper limit is set to 70
The reason for this limitation is that the maximum amount of metal that can be impregnated while maintaining wear resistance at high temperatures is approximately 70% by weight.

Furthermore, it is natural that it is preferable that the entire fireproof member 3 of the tilting gutter is impregnated with metal, but since the hot water contact portion 4 and the molten metal passage 5 are particularly susceptible to severe damage due to slag etc. Also, the amount of metal impregnated in the molten metal passage 5 can be made larger than the amount of metal impregnated in other parts.

Hereinafter, a method for manufacturing a tilting gutter according to the present invention will be briefly described.

First, a refractory raw material of a desired material and an additive such as a binder are mixed at a desired mixing ratio, and the resulting mixture is charged into a mold for a tilting gutter. This is about 350-400℃
A monolithic refractory body having the shape of a tilting trough is obtained by baking at a temperature of .

Next, this monolithic refractory or molded body is preheated to a temperature higher than the melting point of the metal to be impregnated and degassed.The preheated and degassed monolithic refractory molded body is immersed in molten metal and pressurized. The amount of metal impregnation can be determined by adjusting the applied pressure and the porosity when molding the monolithic refractory. After that, polishing is performed again as necessary, and other necessary treatments are performed to manufacture the desired tilting trough.

Hereinafter, test results of the fireproof member of the tilting gutter of the present invention, that is, the metal-impregnated monolithic refractory molded body will be shown and specifically explained.

Infiltration resistance and erosion resistance An alumina monolithic refractory molded body was impregnated with stainless steel by the method described above. The amount of stainless steel impregnated is 0 to 80% by weight based on the maximum weight of the monolithic refractory molded body.

A preheated and degassed monolithic refractory body is immersed in molten metal and pressurized. By this method, metal can be impregnated into the pores of the amorphous refractory molded body. Thereafter, it was varied between the required percentages. The amount of stainless steel impregnated can be adjusted by adjusting the pressure applied in the above method and the porosity of the refractory during molding.

The metal-impregnated monolithic refractory molded body thus produced was exposed to molten steel and slag for 8 hours, and the depth of the slag that had penetrated into the pores of the monolithic refractory or shaped body (hereinafter referred to as slag penetration depth) was measured. ) and the degree of erosion by molten steel and slag (hereinafter referred to as the erosion index).

FIG. 2 is a graph showing the influence of the stainless steel impregnation amount on the slag penetration depth, with the horizontal axis representing the stainless steel impregnation amount and the vertical axis representing the slag penetration depth.

As is clear from this figure, it was found that the slag penetration depth was reduced by impregnating the pores of the alumina brick with stainless steel.

Figure 3 is a graph showing the influence of stainless steel impregnation on the erosion of Kinku-impregnated monolithic refractories, with the horizontal axis representing the stainless steel impregnation amount and the vertical axis representing the erosion index. be.

Erosion index is based on the degree of erosion of an alumina monolithic refractory molded body that is not impregnated with stainless steel (+00)
, which shows the degree of corrosion of alumina monolithic refractory molded bodies impregnated with stainless steel at various impregnation amounts. That is, when the erosion index is less than 100, it indicates that the corrosion is reduced by impregnating the stainless steel, and the corrosion resistance is improved.

As is clear from this figure, it was found that by impregnating the pores of the alumina-based monolithic refractory molded body with stainless steel, the erosion of the monolithic refractory molded body was reduced.

This is because impregnation with stainless steel reduces the apparent porosity of the monolithic refractory molded body and prevents the infiltration of slag and the like. Therefore, it is presumed that this effect can also be obtained when other metals are impregnated instead of stainless steel.

Heat Resistance Spalling Properties - Rapid Cooling Test By the method described above, pig iron was impregnated into the pores of alumina-silica monolithic refractories or shaped bricks in various amounts. The amount of iron impregnation is 20% by weight based on the weight of the refractory material.
and 60% by weight.

The metal-impregnated monolithic refractory molded bodies produced in this way are heated to a predetermined temperature (every 100°C),
Thereafter, the samples were rapidly cooled in water and their respective strengths were measured. A strength index was calculated by dividing each obtained temperature by the refractory strength before heating and quenching.

As a comparative refractory, a similar test was also conducted on an alumina-siliceous monolithic refractory that was not impregnated with metal.

In Figure 4, the horizontal axis shows the quenching temperature difference (Δ
It is a graph diagram in which the heat-resistant spalling properties of monolithic refractory molded bodies with various metal impregnation amounts are indirectly investigated, with T) taken and the strength index of the monolithic refractory molded bodies taken on the vertical axis.

In the figure, the triangles represent the results for an alumina-silica monolithic refractory molded body impregnated with 20% by weight of pig iron, and the white squares represent the results for an alumina-siliceous monolithic refractory molded body impregnated with 60% by weight of pig iron. The white circles indicate the results for comparative refractories.

According to this figure, when the temperature difference becomes about 400°C, the strength of the comparative refractories rapidly decreases. On the other hand, a metal-impregnated monolithic refractory molded body impregnated with 20% by weight of pig iron also exhibits a decrease in strength when the temperature difference reaches approximately 400°C.
The decrease in strength was gradual compared to that of comparative refractories. In addition, the metal-impregnated monolithic refractory molded body impregnated with 60% by weight of pig iron has the same strength as before heating and quenching until the temperature difference reaches approximately 600°C, and even when the temperature difference is greater than that, the strength is comparable. showed a gradual decrease in strength.

■Bending strength test By the method described above, 30% by weight of aluminum guild steel is impregnated into the pores of an alumina monolithic refractory molded body, and the refractory temperature is 2.
The bending strength was measured every time the temperature increased by 00°C.

As a comparative refractory, a similar test was also conducted on an alumina shaped refractory molded body that was not impregnated with metal.

Figure 5 shows the temperature of the monolithic refractory molded product on the horizontal axis and the bending strength of the monolithic refractory molded product on the horizontal axis. FIG. 3 is a graph comparing the breakage strength of molded bodies.

In the figure, the black circles show the results of a monolithic refractory molded body impregnated with 30 m% of aluminum killed steel, and the white circles show the results of a comparative refractory.

As is clear from this figure, it was found that the monolithic refractory molded body impregnated with aluminum killed steel had higher bending strength than the comparative refractory.

The quenching test and bending strength test described above serve as a guideline for examining the magnitude of heat-resistant spalling properties, and it can be generally assumed that the greater the strength and bending strength, the greater the heat-resistant spalling properties M1.

The reason why metal-impregnated monolithic refractories are stable against thermal shocks is thought to be that impregnation with metal increases thermal conductivity and makes it difficult to generate thermal stress.

The tilting gutter of the present invention is formed of a metal-impregnated monolithic refractory molded body having excellent infiltration resistance, erosion resistance, structural spalling resistance, and heat-resistant spalling resistance as described above. It is a matter of course that it has the same effect as the impregnated irregular cedar refractory molded body.

Hereinafter, an example will be shown in which a tilting gutter of the present invention formed of a metal-impregnated monolithic refractory molded body was actually installed and used below the downstream end of a blast furnace main gutter. It is not limited to the examples.

(Example 1) An alumina refractory raw material and alumina cement as a binder are completely mixed, and the resulting mixture is mixed with 5! I
! It was πln at Q96 and charged into a mold for a tilting trough.

This was baked at a temperature of 450° C. to produce an alumina shaped refractory molded body with an apparent porosity adjusted to 23% by volume. Next, this alumina amorphous refractory molded body was preheated to 650° C. and degassed. Thereafter, it was immersed in molten aluminum killed steel, and a pressure of 8 kg/cJ was applied to impregnate the aluminum killed steel. The apparent porosity after metal impregnation was 0.4% by volume.

The tilting gutter of the present invention manufactured in this manner was placed below the downstream end of the blast furnace main gutter, and its lifespan was investigated. The life of this tilting trough was judged to have ended when the wear was 100I1-.

The life of this tilting trough was 150 hours.

(Example 2) An alumina-siliceous refractory raw material and colloidal silica as a binder were thoroughly mixed, and the resulting mixture was charged into a mold for a tilting gutter. This was baked at a temperature of 800° C. to produce an alumina-silica amorphous refractory molded body with an apparent porosity adjusted to 25% by volume. Next, the second alumina-siliceous amorphous refractory molded body was preheated to 1500°C and degassed. Thereafter, it was immersed in molten stainless steel and a pressure of 3 kg/cj was applied to impregnate the stainless steel. The apparent porosity after metallic immersion was 1.4% by volume.

The tilting gutter of the present invention thus manufactured was placed below the downstream end of the blast furnace main gutter, and its design was investigated. The life of this tilting trough was 130 hours.

(Comparative example) Alumina silicon carbide - graphite refractory raw material and alumina cement as a binder are completely mixed, the resulting mixture is kneaded with 5.6% by weight of water, and charged into a mold for tilting gutter. did. This was baked at a temperature of 1000° C. to produce an alumina-silicon carbide-graphite monolithic refractory molded body with an apparent porosity adjusted to 18% by volume.

The tilting gutter manufactured in this way was placed below the downstream end of the blast furnace main gutter, and its lifespan was investigated. The power life of this tilting trough was 70 hours.

[Effects of the Invention] According to the present invention, a tilting gutter with excellent infiltration resistance, erosion resistance, structural spalling resistance, heat spalling resistance, and abrasion resistance is provided.

Thus, the tilting gutter of the present invention has comprehensively improved infiltration resistance, erosion resistance, structural spalling resistance, thermal spalling resistance, and abrasion resistance, thereby extending the service life of the leaning gutter. This allows for smooth ironmaking operations.

[Brief explanation of drawings]

FIG. 1a is a perspective view of a tilting trough according to an embodiment of the present invention. FIG. 1b is a front view of a tilting gutter according to an embodiment of the present invention. FIGS. 2 to 5 are graphs for explaining the effects of the fireproof member constituting the tilting gutter of the present invention, respectively. 1...Tilting gutter, 2...Iron shell, 3...Fireproof member, 4
... Molten metal contact portion, 5... Molten metal passage, 6... Support member, 7... Metal plate, 8a, 8b... Support body

Claims (2)

[Claims] (1) A fireproof member having a contact portion for receiving molten metal and a plurality of molten metal passages branching from the contact portion, and a support member that swingably supports the fireproof member, wherein the fireproof member has a non-contact part. 10 to 7 pieces of metal in a shaped refractory porous body
A tilting gutter characterized in that it is a metal-impregnated refractory molded body impregnated at a ratio of 0% by weight. (2) The tilting gutter according to claim 1, wherein the metal-impregnated refractory molded body is covered with a metal plate, and the support member is fixed to the metal plate.