JPH0324219A - Bottom blowing tuyere - Google Patents

Abstract

PURPOSE:To decrease the attack and erosion by slag and to allow a long-term operation by using a metal impregnated refractory brick formed by impregnating a metal into a porous body of refractories to form the working surface of a bottom blowing tuyere. CONSTITUTION:This bottom blowing tuyere 1 is formed of a gas reserving part 2 having a gas supply pipe 5, a gas blowing brick 3 and an external brick 7 molded to enclose the outer side thereof, etc. The above-mentioned blowing brick 3 is formed of the metal-impregnated refractory brick having many gas blowing passages 4 opened in a vessel for molten metal. The metal-impregnated refractory brick is impregnated with 1 to 100wt.% metal by the weight of the refractories.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an MHP type bottom blowing tuyere used for converter bottom blowing, etc. (Prior art and problems to be solved) For example, , during the converter operation > h, oxygen is blown from 2 oz to improve the stirring power of the molten metal in the converter.
So-called complex blowing is carried out in which stirring gas is blown into the molten metal through the bottom blowing tuyere.

The gas blowing passage of the bottom blowing tuyere is formed by a single or double pipe. When the gas pressure was increased to further stir the molten steel, there was a problem in that the refractory lining 9 around the tuyeres was violently welded together.

Therefore. Recently, a multi-hole delag type bottom-blown tuyere (hereinafter simply referred to as MHP) has been used, which can increase the gas pressure while suppressing the challenge of large-sized sake.

here. MHP is l/c gas reservoir inside refractory (wind box)
Buried. A bottom blowing tuyere with a large number of gas blowing passages connected to the gas reservoir. By applying back pressure to the gas reservoir,
A converter that can inject multiple stirring gases, cooling gases, etc. into the molten steel in a converter at high pressure. Like the conventional tuyere, this MHP #i is installed at the bottom of the converter and has a surface (hereinafter referred to as the operating surface) that comes into direct contact with the molten steel in the converter. Additionally, when the converter is tilted, the operating surface also comes into contact with the slag. For this reason, molten steel Yasuwogu (hereinafter referred to as Su2gu, etc.) easily infiltrates into the pores of the refractories that form the MHP (hereinafter referred to as gas-injected bricks). MHP is prone to erosion and decay. In addition, since the working surfaces in particular come into direct contact with the vigorously agitated molten steel flow, the physical wear caused by the molten steel was reduced. Furthermore, the above-mentioned gas supply pipe. It is installed through the metal around the center of the MHP main body, but when gas is vented through this supply pipe, its cooling effect creates a negative thermal gradient radially around the supply pipe, causing thermal spalling. It was easy to wake up. Apart from that, the working surface and its back (i.e.
Because a thermal gradient also occurred between the steel shell side), thermal spalling was extremely likely to occur. For these reasons, the lifespan of MHP is 2000 to 2300 years.
0H (approximately 670 to 760 hours), MHP exchange p
The roof and surrounding area had to be repaired frequently. As a result, there was a meltdown point where the operating rate of the converter decreased and manufacturing costs increased. Various studies have been carried out to solve the above problems, and oxide refractories such as magnesia-dolomite bricks, magnesia-chromium bricks, i? MHPs made of carbon-containing refractories such as Madanesia and Madanesia carbon bricks and magnesia and calcia carbon bricks have been developed.

However, although MHP made of oxide refractories has excellent corrosion resistance, it has insufficient thermal spalling resistance. In general, oxide refractories are porous, so they are easily penetrated by sulfur, and are prone to melting damage during erosion, which rarely causes structural spalling.

Although MHPs made of carbon-containing refractories have better heat-resistant spalling properties than MHPs made of oxide-based refractories, satisfactory heat-resistant spalling properties have not yet been achieved. However, there were disadvantages in that it was necessary to provide a heat insulating layer with a thickness of 15 to 20 mm around the stirring gas supply pipe made of stainless steel, and the internal structure of the MHP became complicated. In addition, carbon-containing refractories have the disadvantage that the carbon they contain is oxidized, causing the refractories themselves to deteriorate and break.

However, since all of the above refractories are porous, it has been impossible to sufficiently prevent wear caused by the flow of molten steel.The present invention was made in view of the above circumstances, and
The purpose of the present invention is to provide an MHP t-formed with a refractory material that has excellent corrosion resistance, spalling resistance, and wear resistance. [Means for Solving the Problems] An object of the present invention is to provide a gas reservoir connected to a gas supply pipe;
Communicates with the gas reservoir. The gas-injected brick has a large number of gas-injection passages that open into the WI hot water container, and an exterior brick formed to enclose these. Metal t- to weight
This is achieved by means of a separate bottom blowing port characterized by a metal-impregnated refractory brick impregnated in various proportions within the range of 1-100% by weight.

Furthermore, the gas-injected brick has a metal capacity of 1kl to 50% relative to the weight of the refractory in the area on the opening side of the gas-injection passage.
! Impregnate the metal at a ratio of 30 to 100% to the refractory in the region on the gas reservoir side. The range of measurement. This is achieved by a bottom-blown tuyere characterized by being made of metal-impregnated refractory brick impregnated with a certain proportion. Not only as a tuyere,
It can be similarly used in blast furnaces, etc.

[Effect]

Is the bottom blowing tuyere of the present invention impregnated with metal on its operating surface? It is made of firebrick made of refractory material. The so-called impregnated refractories are made by impregnating a porous refractory with gold powder, and the apparent porosity of the refractories is lower than that of ordinary refractories. Therefore, it is possible to prevent erosion and melting damage caused by infiltration of slag, thereby improving the property of subsequent spalling.

By impregnating the refractory with metal, the thermal conductivity of the refractory improves, resulting in better heat dispersion.Since there is a temperature difference between the inside and outside of the refractory, distortion due to differences in thermal expansion is less likely to occur. This improves heat-resistant spalling properties. Furthermore, impregnation with metal increases the refractory density and improves wear resistance.

The bottom-blown tuyere according to the present invention has excellent slag erosion resistance, spalling resistance, and abrasion resistance, so it can be operated for a long period of time.

[Dormitory example]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal cross-sectional view of the bottom blow panel according to the present invention.

The bottom blowing tuyere 1 has a gas reservoir part lε, which has a gas supply pipe 6 metal.
Gold differently impregnated refractory brick with multiple gas injection holes W & 4
3ε, which is equipped with an exterior lens ITε formed so as to surround the outside of the plates. Metal impregnated fireproof: 7f3
17. is a porous refractory material impregnated with gold R. The refractory porous body contains magnesia f. Magnesia chromium brick, 1 gnesia spinel brick, alumina brick. Or fired refractories such as Subinel steel f! l - You can use jin and gold. The metals to be impregnated are stainless steel, chromium, Nikkel,
Aluminum two▲, iron, etc. Any gold horse will do, but I prefer Ni-Cr alloy. Money #
! These can be impregnated into the refractory porous body either singly or in combination.

The amount of the metal impregnated jujube is approximately 1% by weight based on the weight of the porous refractory material.
It can be selected as appropriate within the range of ~100 weights to obtain the desired effect. %, the metal impregnation amount on the working surface side is about 1%.
~5011t96. , It is good that the gold N4 impregnation on the f reservoir side is 30 to 100 layers. In Tomoe, the operating side refers to the portion of about V3 between the operating surface and the gas reservoir, and the F reservoir side refers to the approximately 1/3 portion between the top of the gas reservoir and the operating surface. Kim says that.

The reason why it is preferable to have metal impregnation within the above range on the working side is because the working side requires special properties such as erosion resistance and spalling resistance, so it is important to improve these properties. It takes at least about 1 weight of gold to make it happen! This is because the maximum amount that can be impregnated while maintaining the corrosion resistance and spalling resistance of IL and refractories is approximately 50% by weight. The reason why it is preferable to use a metal-impregnated lid within the above range on the gas reservoir side is because the top surface of the gas reservoir is covered with fireproof material 3.
This is because the gas reservoir part 2 and the gas reservoir part 2 come into contact with each other. In order to perform this welding easily. This is because a metal impregnation amount of at least about 30 tons by weight is required. Furthermore, "metal impregnated xooiis" means "gold", meaning that it is made only of metal. In order to easily perform acid welding of the sand, refractory member 3ε, gas reservoir portion 2ε, it is necessary to weld the lower surface ζ of the refractory member 30, ie. It is particularly preferable that the contact surface of the reservoir portion 2L) is made of only metal.

Tomoe's Kinshin-impregnated refractory brick 3 has an inner diameter of O. A large number of 5 to 5 gas injection passages 4 are perforated. The noteworthy features ε of this Tomoe are that the metal-impregnated refractory bricks 3 have excellent refractory properties, and there is no need to use stainless steel pipes for the gas injection passage 4; a simple tributary hole is sufficient. I'm Iuko L. in this way. Since there is no need to use stainless steel pipes for the injection passage WIr4, the internal structure of the MHP can be made as simple as possible. The gas reservoir section 2 is a gas storage container made of stainless steel. Tomoe's gas reservoir part 2 has a gas supply pipe of 6t.
, this gas supply pipe 6 is connected to the gas pipe 6. usually,
Stainless steel pipes are used for the gas supply pipes. Gases such as stirring gas and cooling gas are accommodated in the gas reservoir 2 via a gas pipe 6 and a gas supply pipe 5. The gas contained in the gas reservoir 2 is injected into the converter through a gas blowing passage 4. Generally, oxygen gas, argon gas, nitrogen gas, or carbon dioxide gas is used as the stirring gas. Natural gas and f-tan gas are used as cooling gas. Alternatively, a hydrocarbon gas such as Delonozane gas is used.

The nine MHPI constructed in this way is installed at the bottom of a converter, etc., like a conventional tuyere. Usually, the MHP is installed parallel to the vertical central axis of the converter, etc., but it can also be installed at an angle to obtain better stirring efficiency. When molten iron is charged into the converter, stirring gas or the like is injected into the molten steel in the furnace through the gas injection passage. The supply of stirring gas, etc. is performed by a gas supply Φ stage (not shown). The gas pressure when gas is supplied can be adjusted appropriately to obtain the desired stirring state. However, if the working surface of the tuyere is immersed in molten iron, it is necessary to apply a gas pressure b4 greater than the static pressure of the molten steel in order to prevent the molten steel from entering the gas injection passage. The method for manufacturing the bottom blowing tuyere of the present invention is not particularly limited, but
For example, the following method can be used.

First, the refractory raw material for the refractory brick, a binder, etc. are filled into a mold and pressure is applied to produce a rectangular refractory brick. When filling the mold with the refractory raw material, an appropriate amount of fiber (for example, hemp or cotton yarn) that is burnt out in a predetermined firing process is added in order to obtain a desired apparent porosity.

When adding fiber, increase the amount of fiber added in some areas and decrease the amount added in other areas. Portions with different apparent porosity can be created within a single refractory porous body. This can also be done by changing the diameter of the added fibers. By obtaining a refractory porous body having parts with different apparent porosity in an integrated refractory porous body in this way, b. An impregnated refractory porous body can be obtained.

A refractory porous body adjusted to a desired apparent porosity is
Preheat to 400-1700℃ and bring to a boil.

Next, immerse it in the desired molten metal and apply pressure (3 to 9k9/min).
al1) is applied.

In this way, a metal-impregnated refractory brick, ft-, in which a refractory porous body is impregnated with metal t-, can be manufactured. For example, a refractory porous body whose apparent porosity is adjusted to 40 m/volume and has a length of 103 m, a width of 133 m, and a height of 120 m can be impregnated with about 45 m/m of N1. 1,
It is possible to impregnate a refractory porous body with an apparent porosity of 30% by volume, a length of 551 cm, a width of 551 cm, and a height of 90 cm by weight of Ni-Cr of about 36% by weight. By drilling a large number of pores in the metal-impregnated refractory brick manufactured in this manner to form gas supply passages 47. Metal-impregnated refractory brick f! s2 can be manufactured.

The obtained 3t metal-impregnated firebrick is welded to the upper surface of the stainless steel gas reservoir part 2. The means for welding is conventional. The amount of metal impregnation in the metal-impregnated firebrick 3 is particularly f
This is because the area of the refractory that will be welded to the sump is set high. Sit can be done easily and reliably. Metal-impregnated refractory lens 7 with welded gas reservoir part 2! /3,
The refractory raw materials such as magnesia and chromium are charged into a mold for Habi molding, and the pressure (100 to 10 Q/ts
) k is applied to obtain a tuyere shape. However, it may be formed only of metal-impregnated bodies. The resulting tuyere shape is. It is shaped into a desired shape by polishing or the like.

Below, the results of various refractory tests on the metal-impregnated firebrick 3 will be explained.

Erosion resistance By the method described above, the magnesia chromium refractory raw material is molded to obtain a porous refractory material. The bricks were impregnated with 50NS-50Cr to obtain metal-impregnated hot bricks having various metal impregnation amounts.

This metal T-impregnated refractory brick was exposed to molten steel and slag for 10 hours, and the degree of erosion by the slag (hereinafter referred to as the erosion index) was examined. Rt-unimpregnated magnesia-chromium refractory bricks were similarly exposed to slag and the erosion chamber due to slag was investigated.

The results are shown in Figure 2. here. fJ! The eclipse index is defined as the food content standard (100) for the corrosion of the comparative refractory bricks. This figure shows the degree of erosion of a gold-impregnated refractory brick impregnated with 50Nl-50Cri. In other words, when the erosion index is less than 100. 508K-
The results show that erosion was suppressed to a small extent by immersing the steel at 500 rft. It is clear from Figure 2,! )． 5 0Nt - 5
0Crt - Erosion caused by impregnation, slag, etc. was suppressed. Heat-resistant spalling property Spalling resistance A porous refractory material obtained by molding the P1 magnesia refractory raw material by the method described above. For this refractory porous book weight, ^
A refractory brick impregnated with gold Ii4 was manufactured by impregnating it with 20% by weight of Tk and 40 parts by weight. Each of these metal-impregnated fire bricks was heated in a cabinet at a predetermined temperature (in increments of 100°C), then rapidly cooled in water, and the strength was measured. The strength index t was calculated by dividing each of the obtained strengths by the strength before heating and quenching.
The relationship between the strength index ε of C and the quenching temperature difference (JT) ε is shown in Figure 3. Here, the triangle shows the result of the metal-impregnated refractory brick impregnated with Atk 40, and the black circle shows the result of Attoo.
The results of the weight-impregnated metal-impregnated refractory bricks show gold. The white circles show the results for magnesia refractory bricks, which are comparative refractory bricks. According to Figure 3, the temperature difference of the comparative refractory bricks is approximately 100℃.
When this happens, a decrease in strength is observed. On the other hand, At1
K20 weight S impregnated metal impregnated refractory brick Fi temperature difference is about 300'C in the case, 40 heavy ES impregnated metal impregnated refractory brick in the case has a temperature difference of about 700'C, equivalent to the temperature difference in case ■Bending strength test Using the method described above, FF gnesia refractory bricks were
Metal-impregnated refractory bricks named 30% weight and 30% weight were manufactured. ? :． A metal-impregnated refractory brick was gradually heated, and the bending strength t was measured as the refractory temperature rose by 200°C. The relationship between this bending strength and heating temperature is shown in FIG. In this figure, the autotriangle is F@f 3 0 l
Gold is the result of gold impregnated with a lot of lit. The black circle is F @ Gold 158t. Gold I is impregnated with a lot of lit! 4 Results of impregnated refractory bricks are shown. The white circles indicate the results of magnesia refractory bricks, which are comparative refractory bricks.

It is clear from Figure 4 that the bending strength of the gold 1F4-impregnated firebrick was higher than that of the comparison firebrick. As described above, the metal-impregnated refractory brick used in the bottom blowing tuyere of the present invention can reduce erosion by slag and the like. Compared to conventional refractory bricks, the reduction in strength and bending strength at high temperatures is suppressed, resulting in improved spalling resistance and wear resistance. Therefore, by attaching this metal-impregnated refractory brick to the operating surface, it is expected that the erosion resistance and spalling resistance of the bottom blowing tuyere of the present invention will be improved.

Below, bottom-blown tuyere equipped with metal-impregnated firebrick (M
An example in which HP) was actually produced and used in a converter will be given.

(Example 1) By the method described above, the size is 30 cm long x 40 α wide x 6 height
A 0 cm 7 gnesia refractory shaped body was manufactured.

The apparent porosity of this refractory molded body is approximately 40 from the operational point of view.
The part up to α is 20 volume da, the other parts are 50 volume fl.
ts&c adjusted.

This refractory porous body was preheated to 1600°C and immersed in molten stainless steel. Next, a pressure of 4.0 kg/cyt2 was applied, and the stainless steel was 29 weight heavier in the area at about 40 CrILt from the operating surface, and the stainless steel was 52 weight heavier in the other areas.
Metal-impregnated refractory bricks with heavy weight impregnation were manufactured. After that, the inner diameter is 0. A gas supply passage of 5 nm was perforated, and the side of the metal-impregnated refractory brick with a large amount of metal impregnation was welded to the gas reservoir (made of stainless steel). This was charged into a tuyere mold together with the Magnesi T carbon refractory raw material. MHP was manufactured by applying a pressure of 1000ψh2. The obtained MHP was installed at the bottom of a converter, and its lifespan was measured. M}{p's lifespan was judged to have ended when 35 sections were worn out. The life of this M}{P was 700 hours.

(Example 2) From the method described above, the length is 50 cIRX, the width is 50 m, and the height is 60 m.
A CIL magnesia-chromium refractory molded body was manufactured. The apparent porosity of this refractory material is approximately 4
The volume at 0 cm t is adjusted to 30 volume, and the other parts are adjusted to 60 volume.

This refractory porous body was preheated to 1500°C and immersed in Fe-Cr molten metal. Next, 7. A pressure of 0 k9/cru2 was applied, and Fe-(
h is 38 weight fly, other parts are Fi F{:r is 57
A heavily impregnated metal-impregnated refractory brick was produced. After that, the inner diameter is 1. The gas supply passage of the Ovtyi was perforated, and the side of the metal-impregnated refractory brick with a large amount of metal impregnation was welded to the gas reservoir part (stainless steel) to produce a gas tank.

The obtained MHP was installed at the bottom of the converter furnace and its life was measured.
The life of this MHP was 650 hours.

(Comparative example) A raw material for magnesia charcoal refractory was used with an inner diameter of 1. 0
2000 kI filled in a stainless steel pipe of m and a wind box enclosure.
Apply pressure of I/crI12, 50φX 60cm
I manufactured it myself. The apparent porosity of this MHP is 5.0
▼oL%. The resulting sheet was placed in the bottom of a converter, and its lifespan was measured.

The lifespan of this notebook was 400 hours.

It has been found that the life of the bottom blowing tuyere of the present invention as mentioned above is extended compared to the conventional bottom blowing tuyere. this is,
This is because by applying metal-impregnated refractory bricks to operating surfaces, erosion resistance, spalling resistance, and wear resistance are comprehensively improved.

〔Effect of the invention〕

According to the present invention, there is provided a bottom blowing tuyere which reduces erosion by slag and has excellent spalling resistance. The bottom-blowing tuyere of the present invention is capable of long-term operationb, and by using this bottom-blowing tuyere, the operating rate of a converter or the like can be increased, so that manufacturing costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a bottom blowing tuyere according to an embodiment of the present invention. 2 to 4 are graphs showing the effects of the embodiment of the present invention. 1... Bottom blowing tuyere (MHP), z... Gas reservoir section, 3... Gold wing impregnated refractory brick, 4... Gas blowing passage.

Claims (2)

[Claims] (1) A gas reservoir connected to a gas supply pipe, a gas blowing brick having a large number of gas blowing passages communicating with the gas reservoir and opening into the molten metal container, and a gas blowing brick that encloses these. at least the gas-injected bricks have a metal content of 1 to 10% by weight of the refractory.
A bottom-blown tuyere characterized in that it consists of metal-impregnated refractory bricks impregnated in various proportions within the range of 100% by weight. (2) The gas injection brick is impregnated with metal at a ratio of 1 to 50% by weight based on the weight of the refractory in the area on the opening side of the gas injection passage, and in the area on the gas reservoir side. The bottom blowing tuyere according to claim 1, characterized in that it is made of a metal-impregnated refractory brick impregnated with metal at a ratio of 30 to 100% by weight based on the refractory material.