JPS6324008A - Gas blowing plug - Google Patents

Abstract

PURPOSE:To easily produce a plug and to extend the life thereof by integrating a nozzle brick formed with gas flow passages and sleeve brick enclosing the nozzle brick thereby forming a gas blowing plug. CONSTITUTION:The gas blowing plug 10 having a trapezoidal quadrangular pyramidal section is formed of a nozzle region 12 in the central part and a sleeve region 14 formed around the nozzle region 12. Plural gas communicating pipes 16 are embedded at equal intervals in the nozzle region 12. The sleeve region encloses the nozzle region 12 and is formed to the size of the thicknesses increasing gradually from the top toward the root end of the gas blowing plug 10. Such gas blowing plug 10 is integrally formed with the nozzle region 12 and the sleeve region 14 and has no joint parts; therefore, the entire part is approximately uniformly and gradually eroded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a gas injection plug for supplying gas to hot metal or molten* from the bottom of a converter or ladle.

[Conventional technology]

For example, when molten steel is subjected to tN refining in a converter, argon gas (Ar) is introduced from the bottom of the converter to stir the molten steel in the converter.
A compound blowing method is known in which decarburization is performed by supplying oxygen gas (03 gas) from above the converter while blowing an inert gas such as molten steel into the molten steel.

A converter used in such a composite blowing method is provided with tuyeres for supplying stirring gas to the bottom of the furnace. The tuyere is equipped with a gas injection plug in which a large number of gas passages are formed in a refractory brick to facilitate adjustment of the amount of gas blown into the tuyere.

As shown in FIGS. 4 and 5, a conventional gas blowing plug 1 is provided with a nozzle brick 3 in which a gas passage 2 extending from a base end to a distal end is formed. The nozzle brick 3 is surrounded by a sleeve brick 4 formed separately from the nozzle brick 3. Further, the sleeve brick 4 has a total of eight blocks, including four sleeve brick pieces 5 surrounding the upper part and four sleeve brick pieces 5 surrounding the lower part of the nozzle brick 3, which are each formed separately. The brick is divided into 5 pieces.

When the nozzle brick 2 and the sleeve brick 3 are formed separately in this way, as shown in FIG.
A joint (gap) 7 is formed between the sleeve brick 3 and the sleeve brick 3. Also, since the sleeve brick 3 is formed from sleeve brick pieces 5 that are each formed separately,
Joints 8 are formed between the sleeve brick pieces 5 which are in contact with each other.

Further, when the sleeve brick piece 5 divided into a plurality of pieces is entirely enclosed around the nozzle brick 2, high precision is required to bring the nozzle brick 2 and the sleeve brick piece 5 into close contact with each other.

[Problem that the invention seeks to solve]

However, if there are joints formed in the gas injection plug, the molten steel will enter the joints and damage the bricks when gas is injected into the molten steel. The blow plug is unevenly eroded, that is, the joint 7 is damaged.

There is a problem in that the life of the gas injection plug is short because it is more noticeable compared to other parts.

Furthermore, when surrounding the sleeve brick piece 5 around the nozzle brick 2, there is a problem in that it takes time and effort to make the M-shape of the gas blowing plug in order to ensure close contact with high precision.

This invention was made in view of such circumstances.

It is an object of the present invention to provide a gas blowing plug that is easy to manufacture and has a long life.

°A gas blowing plug according to the present invention is a gas blowing plug for blowing gas into molten metal, and includes a nozzle brick in which a gas passage is formed and a sleeve brick that surrounds and supports the nozzle brick. It is characterized by being

[Effect]

According to the gas blowing plug of the present invention, there are no joints because the nozzle brick in which the gas passage is formed and the sleeve brick that surrounds and supports the nozzle brick are integrally formed.

Therefore, significant damage to the joints is prevented, and the entire area is gradually and evenly eroded.

In addition, when manufacturing the gas blowing plug with W, the nozzle brick is formed with a dimension including the thickness of the sleeve brick.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 3 of the accompanying drawings.

As shown in FIGS. 1 and 2, the gas blowing plug 1011C, which is formed in the shape of a truncated quadrangular pyramid with one section being a trapezoid, is formed around the nozzle area 12 and the ek area 12 in the approximately central part. A sleeve region 14 is provided. In the nozzle region 12, a plurality of passage pipes fxe extending along the longitudinal direction of the gas blowing plug 10 are embedded at equal intervals. The proximal ends of these gas blowing tubes 16 are connected to a gas distributor 18, respectively. The nozzle region 12 includes a gas blowing pipe and extends approximately in the center of the gas blowing plug in a cylindrical shape.

On the other hand, the sleeve region 14 surrounds the nozzle region 812,
The gas blowing plug 10 is formed to gradually become thicker from the distal end to the proximal end.

As described above, in the gas blowing plug 10 according to the present invention, the nozzle region 12 and the sleeve region 14 are integrally formed 9, and no joint is formed to divide these regions.

When installing the gas injection plug 10 at the bottom of the converter, the first
As shown in the figure, the sleeve region 14 is embedded in the lining bricks 20 of the converter so that the circumferential surface of the sleeve region 14 is in close contact with it. The lining bricks 20 are formed in two stages, a lower stage 20k and an upper stage 20B.

Next, the method for manufacturing the gas injection plug will be explained. A mold formed in advance in the shape of a truncated quadrangular pyramid with a trapezoidal cross section is filled with carbon brick material containing magnesium oxide (MgO) as a main component, and metal arm ribs 16 for gas passages are arranged. The gas passage pipes 16 are installed approximately at the center at equal intervals.

The mold filled with brick material is subjected to so-called rubber pressing and then heated to approximately 200 to 300°C to harden it. Next, after processing the outer shape of the nozzle to a certain size, the gas distributor 18 is formed by welding.

In the gas blowing plug according to this embodiment, the nozzle region and the sleeve region are integrally formed, so that damage to the joint can be prevented. Furthermore, it can be manufactured by simply embedding the gas passage pipe while filling the formwork with bricks.

Example 1 Two gas injection plugs according to this example were installed at the bottom of a 250-ton composite blowing furnace, and bottom blowing gas was blown into the molten steel in the converter. Carbon dioxide gas (Co2 gas), argon gas (Ar gas), and nitrogen gas (N2 gas) were used as bottom-blown gases.

What is the thickness of the lining brick 20 formed at the bottom of the converter? 0A540 gourd, upper row,? (78630■ total 1
1701111, 85 to 91 stainless steel pipes with an inner diameter of 1.5 m to 2.0 cm were embedded in the gas passage pipe of each gas blowing plug.

The brick material for each gas injection plug was MgO Kagen brick, which has excellent spalling resistance and slag resistance.

When the damage of the two gas injection plugs according to this example was measured, one gas injection plug was damaged by 0.7 inches per charge, and the other gas injection plug was damaged by 0.8 inches.
m damage, one has 1595 charges and the other has 14 charges.
A life of 10 charges was obtained. In this case, when the residual thickness of each gas injection plug was measured using a residual thickness measuring device using radar light M, as shown in Fig. 3, the residual thickness of the gas injection plug was -like. Only the joint between the tension brick 20 and the gas injection plug was deeply damaged by 30 to 50 degrees.

As described above, there was hardly any difference in the thickness of the remaining brick between the gas injection plug and the lining brick 20.

Comparative Example 1 A conventional gas injection plug as shown in FIG. Two plugs were installed. This conventional gas blowing plug has a nozzle brick and a sleeve brick formed separately, and a sleeve brick surrounding the nozzle brick. The other configurations and materials of the conventional gas blowing plug are the same as those of the first embodiment.

When the damage of the two gas injection plugs according to this comparative example was measured, one had damage of 1.0 nm per charge, the other had damage of 1.1 nm per charge, one had damage of 1120 nm, and the other had damage of 1.1 nm per charge. had a lifespan of 1072 charges. In this case, when the remaining thickness was measured using a radar beam, it was found that the joint 7 between the nozzle brick and the sleeve brick was severely damaged, as shown in Figure 6. The difference is about 150 to 250m
Met.

Example 2 This Example 2 differs from Example 1 only in the thickness of the lining brick formed at the bottom of the 320-ton composite blowing furnace. That is, the lower tier of lining bricks 20 A 630
mlls upper row 20B is in 810th tone and has a total length of 1440m. Two gas blowing plugs similar to those used in Example 1 were installed at the bottom of this converter to perform composite blowing.

When the damage of two gas injection plugs according to this example was measured, one gas injection plug was damaged by 0.75 m per charge, and the other gas injection plug was damaged by 1.
0.80 ■ damage per charge, one side is 1840
charge, and the other had a life of 1725 charges.

Comparative Example 2 At the bottom of the 320-ton combined blowing converter used in Example 2, two conventional gas injection plugs as shown in FIG. I installed one.

When the damage to the two gas blowing plugs according to Comparative Example 2 was measured, one had damage of 1.05 m per charge, the other had damage of 0.95 m per charge; The life of one was 1,313 charges, and the other was 1,425 charges.

As is clear from Examples 1 and 2, according to the present invention, there is no joint between the nozzle brick and the sleeve brick, so the thermal conductivity between the sleeve brick and the nozzle brick is high;
The heat of the sleeve brick can be cooled by bottom blowing gas through the nozzle brick. Therefore, the chemical reaction equation (FeO+ C-+ Fa + Co
) is suppressed. It can be inferred that. As described above, according to the present invention, the gas blow plug is uniformly melted by suppressing the melt damage of the sleeve brick, so that the life of the gas blow plug can be further extended.

Further, according to the present invention, since the sleeve brick and the nozzle brick are uniformly damaged by melting, there is no need to partially replace only one of them that has melted quickly to extend the life.

Further, according to the present invention, since the nozzle brick and the sleeve brick are integrally formed, it requires less time and effort than the conventional case where each brick is formed separately and then processed.

This invention is not limited to the one embodiment described above, and can be modified in various ways without departing from the gist of the invention.

For example, the number of gas passages formed in the nozzle brick may be limited to 11 vA. Further, the gas passage is not limited to a pipe shape, but may be a passage formed of porous material (so-called -1 las plug).

The materials used for nozzle bricks and sleeve bricks are not limited to magnesium oxide (MgOC) containing carbon, but also magnesium oxide (Mgo-cr2) containing chromium oxide.
03) *Magnesium oxide containing aluminum oxide (
Mg0-AA, o3), aluminum oxide u20S
, aluminum oxide containing silicon oxide (AtgOs)
*Similar effects can be obtained with zircon, etc.

〔Effect of the invention〕

According to this invention, since the nozzle brick and the sleeve brick are integrally formed, it is possible to provide a gas blowing plug that is easy to manufacture and has a long life.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a gas blow plug according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the gas blow plug shown in FIG. 1, and FIG. 3 is a cross-sectional view of the gas blow plug shown in FIG. 1. 4 is a longitudinal sectional view showing a conventional gas injection plug, and FIG. 5 is a longitudinal sectional view showing a conventional gas injection plug. FIG. Yuyu, 1, □6. Yu, tsu. , is a vertical cross-sectional view showing a state of melting and damage of an off-line plug. lθ...Gas blowing plug, 12...Nozzle area (
Nozzle brick), 14...Sleeve area (three! brick), 16...Gas passage no4i/. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 Factors Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] A gas blowing plug for blowing gas into molten metal, characterized in that a nozzle brick in which a gas passage is formed and a sleeve brick that surrounds and supports the nozzle brick are integrally formed. plug.