WO1996037632A1

WO1996037632A1 - Nozzle for blowing gas into molten metal and usage thereof

Info

Publication number: WO1996037632A1
Application number: PCT/JP1996/001356
Authority: WO
Inventors: Hiroshi Yamada
Original assignee: Japan Casting & Forging Corporation
Priority date: 1995-05-25
Filing date: 1996-05-23
Publication date: 1996-11-28
Also published as: KR970704892A; JP3894502B2; DE69615508T2; JPH0941024A; KR100349870B1; CN1053015C; EP0776983B1; EP0776983A4; CN1154720A; DE69615508D1; CA2195541A1; EP0776983A1

Abstract

A nozzle for blowing a gas into a molten metal in a stable manner without causing the leakage of gas from its periphery, which has a simple structure and a long life, so that it does not require frequent replacements. The gas blowing nozzle comprises a refractory block formed unitarily with a metallic mounting member and provided with a small diameter through hole therein, and a small-diameter metallic gas blowing tube inserted slidably through the small-diameter hole. When the gas blowing nozzle and the surrounding refractory are worn, the metallic gas blowing tube is extended into the interior of a furnace, and a worn portion is repaired by packing a repairing material therein.

Description

Description Gas injection into molten metal and its use [Technical field]

TECHNICAL FIELD The present invention relates to a gas injection nozzle for molten metal in an electric furnace or other refining furnaces, and particularly to a gas injection nozzle for molten metal that can easily and promptly perform repairs at the time of loss due to loss of the nozzle. How to use.

[Background technology]

FIG. 5 is an explanatory view of an example of a conventionally used gas injection nozzle. FIG. 5 (a) is an example of a single pipe nozzle, FIG. 5 (b) is an example of a double pipe nozzle, FIG. Figure (c) is an example of a multi-tube buzzard, and Figure 5 (d) is an example of a porous plug. In the figure, (10) is a gas supply pipe, (11) is a furnace bottom refractory, (12) is a blowing gas, (17) is a cooling gas supply pipe, and (18) is a porous brick. Among them, Fig. 5 (c) As a multi-tube nozzle, there is a refractory block in which a plurality of thin metal pipes are embedded. It is considered to be preferable because bubbles of blown gas of uniform size can be obtained, and it is widely used as a gas blow nozzle provided at the bottom of an electric furnace.

When gas is injected into the molten metal using the gas injection nozzle, the molten metal flows strongly around the gas injection nozzle 内側 inside the furnace, and the refractory is more worn away than other parts. When repeated, a worn portion (8) as shown in FIG. 2 (a) is generated. When the wear progresses and the worn part (8) becomes large, repairs are performed to replace the gas injection nozzle. However, this repair reduces the productivity of the furnace because the furnace is stopped and repairs are performed. The working environment is bad. For this purpose, frequently use gas injection nozzles. It is not preferable to replace it with a new one.

Japanese Patent Application Laid-Open No. 58-819337 discloses a means for simplifying buzzard repair work.

A refined gas blower comprising a nozzle made of a refractory having a through hole and a thin metal tube inserted into the through hole, wherein an annular gap is provided between the through hole and the thin metal tube. Plug "is disclosed.

Fig. 6 is an explanatory view of this purified gas blowing plug. As shown in Fig. 6 (a), a gap is provided between the refractory nozzle and the metal thin tube, and the metal thin tube and the gas supply tube are connected. The annular gap should be large enough to prevent molten metal from leaking. At the time of repair, it is intended to simplify the work by replacing only the thin metal tubes.

However, when gas is injected with a nozzle having such a structure, when the pressure of the molten metal is applied, as shown in Fig. 6 (b), the gas does not enter the molten metal and the thin tube and the refractory It leaks into the gap of the through hole. In particular, when the gas injection flow rate is small, such as when gas is injected from the bottom of an electric furnace, the gas leaks to the easy-to-pass gap even with a small gap, and does not enter the molten metal. The publication does not disclose any means for solving such a problem.

[Disclosure of the Invention]

According to the present invention, since the frequency of replacement of the gas injection nozzle is low, the productivity is rarely reduced, and the work of replacement in a bad working environment can be reduced. The goal is to provide a gas injection nozzle that does not leak and how to use it.

FIG. 1 is an explanatory view of an example of a gas injection nozzle of the present invention. FIG. 1 (a) is an explanatory view of a longitudinal section of a gas injection nozzle, and FIG. 1 (b) is an explanatory view of FIG. 1 (a). Fig. 1 (c) shows the gas injection nozzle and the supply gas injection nozzle. It is explanatory drawing of the example of the connection part of a case.

The present invention relates to a refractory book (4) provided with pores (3) penetrating linearly from the inside of the furnace to the outside of the furnace, and a mounting bracket formed integrally with the refractory block (4). (22); a metal thin tube (2) slidably disposed through the pores (3) in the pores (3) of the refractory block (4); A connection fitting (23) for connecting an end of the metal tube (22) to the gas blowing hose (15); and a furnace outside end of the thin metal tube (2) being connected to the connection fitting (23). The gas (12) is supplied to the outside of the furnace of the thin tube (2) of metal by blowing the gas (12) into the molten metal from the inner end of the furnace. A gas injection nozzle for molten metal.

One end of the mounting bracket (22) is a straight tube, and the other end is formed in a pan shape conforming to the shape of the bottom of the refractory block (4), and the refractory block (4) receives the mounting bracket (22). Fitted and adhered to the dish-shaped part. By integrally forming the refractory block (4) and the mounting bracket (22) in this way, as shown in FIG. 6 (b), the metal thin tube (2) and the refractory block (4) are formed. Leakage of the gas blown from the gap with the air can be prevented.

As can be seen in FIG. 1 (c), the straight tubular end of the fitting (22) is connected to one end of a connecting fitting (23), and the other end of the connecting fitting (23) is connected to a gas blowing hose ( Linked to 15).

The end of the thin metal tube (2) penetrates the rubber (14) arranged in the connecting fitting (23) and protrudes toward the gas injection hose (15). The gap between the outer circumference of the thin metal tube (2) and the inner surface of the connecting fitting (23) is sealed with rubber (14), and all the blowing gas (12) sent from the gas blowing hose (15) is made of metal. Is supplied into the thin tube (2).

Fig. 1 shows the case where there is one metal thin tube (2). Even if there are a plurality of thin tubes, the gap between the outer periphery of each thin tube and the inner surface of the connection fitting is similarly sealed with rubber, All blowing Charge gas can be distributed to each capillary.

As shown in FIG. 1 (b), the gas injection nozzle (1) of the present invention is mounted inside the tuyere brick (6) provided on the hearth refractory (11) and the support ring (21). And the metal fittings (20). At this time, the size of the gap between the nozzle and the tuyere brick is not limited, but it is filled with irregular-shaped refractories such as mortar and castables.

As the metal thin tube (2), for example, a stainless steel pipe having an inner diameter of 1 to 2 mm can be used, but the inner diameter and the number of the thin tubes can be appropriately selected according to the amount of gas to be blown. The thin tube may be a single tube or a double tube. The inner diameter of the pores (3) should be larger than the outer diameter of the thin metal tube in the range of 0 to 4 mm so that the thin metal tube (2) can slide.

FIG. 2 is an explanatory view of an example of a method of using the gas injection nozzle according to the present invention. When the gas injection nozzle (1) of the present invention is also used repeatedly, the inside of the furnace of the gas injection nozzle (1) and its surroundings have greater wear of refractories than other parts, as shown in FIG. 2 (a). The wear part (8) is generated as described above. In repairing the worn part (8), the present invention slides the metal thin tube (2) upward in the small hole (3), and as shown in FIG. Protrude.

Next, as shown in FIG. 2 (c), the worn portion (8) is filled with a fire-resistant repair material (16) without closing the inside end of the thin metal tube (2). In this example, the inner end of the metal tubule (2) protrudes further from the surface after completion of the filling of the repair material (16), but when the metal tubule (2) protrudes in this manner, Even if the worn part (8) is repaired with a normal in-furnace repair material using a normally used repair device such as a sand slinger, the inside end of the thin metal tube (2) is repaired. It is not buried in the material (16) and does not block.

Therefore, when the gas injection nozzle 1) of the present invention is used, the gas injection nozzle and its Can be easily repaired at the same time as the repair of the worn part of the hearth and the furnace wall, which is performed as a daily work, and the repair of the daily work extends the life of the gas injection nozzle and increases the gas injection. The frequency of nozzle replacement is significantly reduced.

When gas is injected into the molten metal after repairing as shown in Fig. 2 (c), the protruding part of the thin metal tube (2) is immediately melted and damaged, and the gas injection port into the molten metal is injected. Has the same shape as the gas inlet shown in Fig. 1 (b). Therefore, stable gas injection into the molten metal can be performed as in the case of FIG. 1 (b).

FIG. 3 is an explanatory view of an example of another gas injection nozzle of the present invention. FIG. 3 (a) is an explanatory view of a longitudinal section of the gas injection nozzle, and FIG. 3 (b) is FIG. FIG. 3A is an explanatory view in which the gas injection nozzle of FIG.

The gas injection nozzle in Fig. 3 (a) is characterized in that the refractory block (4) is vertically divided into two sections, and the other structure is the gas injection nozzle in Fig. 1 (a). Same as nozzle. As shown in Fig. 1 (c), the end of the mounting bracket (22) in Fig. 3 (a) is connected to the gas blowing hose (1) via the connecting bracket (23), The outer circumference of the pipe (2) is sealed by the rubber (14) as in the case of the gas injection nozzle in FIG.

Also, as shown in Fig. 3 (b), this nozzle is mounted inside the brick (6) provided on the hearth refractory (11), and the support ring (21) and the stopper (20) are installed. Is attached to the furnace skin (19). At this time, the size of the gap between the nozzle and the tuyere brick is not limited, but it is filled with irregular refractories such as mortar and castables.

FIG. 4 is an explanatory view of an example of a method of using another gas injection nozzle of the present invention shown in FIG. When repairing the worn part (8) as shown in Fig. 4 (a), the metal tubing (2) is slid upward through the pores (3) so that the end protrudes inside the furnace. Remove the upper part (4a) of the damaged refractory block. Next, as shown in Fig. 4 (b) Then, install the upper part (4a) (hereinafter referred to as “repair brick”) of the new refractory block, and fill the surrounding wear part (8) with the refractory repair material (16). Then, slide the metal tube (2) downward until the upper end of the metal tube (2) is flush with the upper surface of the repair brick (4a).

By using the repair brick in this way, the nozzle life after the repair can be extended as compared with the case where the repair is performed using only the amorphous refractory repair material. In addition, since the metal tubule (2) does not protrude after the repair, the number of use of the tubule can be increased.

[Brief description of drawings]

FIG. 1 is an explanatory view of an example of a gas injection nozzle of the present invention.

FIG. 2 is an explanatory diagram of an example of a method of using the gas injection nozzle according to the present invention.

FIG. 3 is an explanatory view of an example of another gas injection nozzle of the present invention.

FIG. 4 is an explanatory diagram of an example of a method of using another gas injection nozzle of the present invention. FIG. 5 is an explanatory view of an example of a conventionally used gas injection nozzle. FIG. 6 is an explanatory view of a conventional fine gas blowing plug.

[Best Mode for Carrying Out the Invention]

In the refractory block (4) shown in Fig. 1 (a), a single hole (3) with an inner diameter of 5 mm through which a metal thin tube (2) is passed is provided, and gas is injected from the bottom of the furnace with an electric furnace. Used as a nozzle for The metal tubule (2) has an inner diameter of 2 mm, an outer diameter of 4 mm, and a length of 2 m. The metal tubule (2) is supplied using the connection fitting (23) shown in Fig. 1 (c). Connected to gas injection hose (15).

The gas injection volume during melting and refining is 30-100 lZmin. When the inside of the furnace of the gas injection nozzle (1) has worn out by about 200 mm, the supply gas injection hose (15) shown in Fig. 1 (c) was removed, and the tip of the metal thin tube (2) on the inside of the furnace was removed. The metal tube is slid until it reaches the furnace bottom surface height after repair, and then the connection fitting (23) and the supply gas injection (15). The repair material used was ordinary refractory repair material (16) used for hearth repair. In order to prevent the end of the inside of the furnace of the metal thin tube (2) from being clogged, the gas was blown from the gas blowing nozzle while the repair material was being filled.

After repeating this repair operation 4 to 5 times, the metal tubing (2) was replaced with a new one, and further operations and repairs were performed. When sliding the metal thin tube (2) or replacing it with a new one, molten metal was sometimes inserted into the gap between the pores (3) and the metal thin tube (2) and solidified. By hitting the metal tube (2) from below, the metal tube (2) could be easily slid.

When the erosion length of the gas injection nozzle (1) inside the furnace reached 300 mm, the gas injection nozzle (1) was replaced with a new one. The nozzle can be used for more than 300 charges, and its life is remarkably improved compared to the conventional gas injection nozzle that was replaced every about 50 charges.

Next, the effect of improving the nozzle life with the gas injection nozzle having the split structure shown in Fig. 3 was investigated. Table 1 shows an example of comparison of nozzle life with the gas injection nozzles in Fig. 1 and Fig. 3.

1

Case 1 in Table 1 shows a case where the nozzle with the split structure shown in Fig. 3 was used and repaired with a repair brick. After performing the gas injection operation for 170 to 200 hours, remove the eroded refractory block (upper part), slide the metal tube up above the repair brick, and then fire A repair brick of the same shape as the block (upper part) of the object was glued to the block (lower part) of the refractory with an adhesive. At this time, the gap between the thin metal tube and the pores of the repair brick was also filled with non-breathable refractory.

After that, the eroded part of the tuyere brick (upper) was filled with irregular-shaped refractories to complete the first recovery. The second to fifth repairs were performed every time the machine was used for 170 to 200 hours. The tuyere bricks (upper) were also replaced during the even-numbered repairs.

The refractory block (upper part) and the repair bricks used had a length of 200 faces, but the remaining dimensions at the time of the repair were 50 to 100. In addition, the nozzle was replaced for inspection after using it for 170 to 200 hours after the fifth repair, but the refractory block (lower part) did not show any erosion and could be used continuously. It was in a state.

Case 2 in Table 1 shows the case of using the monolithic nose ^ shown in Fig. 1 and repairing it only with irregular refractories. -After performing the gas injection operation for 170 to 200 hours, slide the metal thin tube upward to the height corresponding to the erosion loss part, and the erosion of the tuyere brick and the refractory block Repairs were made to fill the sections with irregular refractories.

After that, the same repair was carried out three times every use for 80 to 100 hours, and after 80 to 100 hours use, the Nozunore and tuyere brick (upper part) were replaced. At this point, the nozzle erosion size was 250 to 300, and no erosion of the tuyere brick (middle) was observed. However, if the repair was repeated and the use continued, the tuyere brick was used. Before the repair work was completed, replacement of the Nozose and tuyere bricks (upper) was carried out because the bricks were melted down to the middle (middle) and it was difficult to replace the bricks within the specified repair time.

As can be seen in Table 1, the nozzle with the split structure in Case 1 The service life and the number of standard repairs were increased, and the total nozzle life of one nozzle could be greatly extended.

[Industrial applicability]

When the gas injection nozzle of the present invention is used, the frequency of shutting down the furnace for replacing the gas injection nozzle is reduced, so that the productivity is rarely reduced, and the replacement work in a bad working environment is reduced. can do. Further, since the structure of the nozzle is simple, the nozzle can be manufactured at low cost.

Claims

The scope of the claims

1. Refractory block (4) provided with pores (3) linearly penetrating from inside the furnace to outside of the furnace, and mounting bracket (2 2) integrally formed with the refractory block (4) A metal thin tube (2) slidably disposed in the pores (3) of the refractory block (4) through the pores (3); and the mounting bracket (2). A connection fitting (23) for connecting an end of the metal tube (2) to a gas injection hose (15); and a furnace fitting end (23) of the metal thin tube (2) on the outside of the furnace. The gas (1 2) is supplied to the outside of the furnace of the metal thin tube (2) by passing through the rubber (1 4) arranged in the furnace, and the blowing gas is blown into the molten metal from the end inside the furnace. Characterized by gas injection nozzles for molten metal.

2. In a furnace provided with a gas injection nozzle for molten metal according to claim 1, when repairing the gas injection nozzle on the inner side of the furnace and a worn part (8) around the nozzle, the metal thin tube is used. (2) slides inside the pores (3) to protrude inside the furnace, prevents the end of the metal tubule (2) inside the furnace from being clogged, and fires the worn part (8) A method for using a gas injection nozzle for molten metal, characterized by filling a repair material (16).

3. The gas injection nozzle for molten metal according to claim 1, wherein said refractory block (4) is vertically divided into two or more blocks. Gas injection nozzle.

4. In a furnace provided with a gas blowing nozzle for molten metal according to claim 3, wherein the gas blowing nozzle inside the furnace and a worn part (8) around the nozzle are repaired, (2) is slid inside the pores (3) to protrude into the furnace, prevents the end of the metal tubule (2) inside the furnace from being clogged, and repairs the worn part of the nozzle (8). A method of using a gas blown nozzle for molten metal, characterized by adding a refractory block for use and filling a worn part (8) with a refractory repair material (16) around the refractory block.