JPH0539522A - Lance pipe for injecting gas - Google Patents

Abstract

PURPOSE:To prevent damage at a position near a gas discharging hole and to drastically improve the service life. CONSTITUTION:A cylindrical refractory brick 10 having erosion resistance is fitted as insertiable into/separable from outer periphery of the gas discharging holes 8, 9 in a core pipe 1, and by covering a part of the refractory brick 10 and large part of the core pipe 1 with monolithic refractory 14, the refractory brick covering outer periphery of the core pipe near the gas discharging hole can be changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas injection lance pipe for injecting a required gas for processing molten metal in a steel ladle, such as a molten steel desulfurization lance and a hot metal temperature adjusting lance for steelmaking. Regarding

[0002]

2. Description of the Related Art Conventionally, a gas injection lance pipe of this kind has a gas discharge end (in FIG. 5) formed on the outer circumference of a metal core tube 21 as shown in FIGS. 5 and 6 exemplifying an oxygen injection lance pipe. Is covered with an amorphous refractory material 22 such as castable refractory material or plastic refractory material from the lower end) to most of the vicinity of the gas introduction end (upper end in FIG. 5). The core tube 21 has a double tube structure in which an inner tube 23 and an outer tube 24 having different outer diameters are concentrically provided by interposing a plurality of gap spacers 25, and the upper end opening of the inner tube 23 is provided with oxygen gas. Of the gas introduction port 26 and the small-diameter short pipe provided outside the upper end of the outer pipe 24 are used as the gas introduction port 27 of an inert gas such as nitrogen gas, while the lower end openings of each are used as the gas discharge ports 28 and 29. ..

Reference numeral 30 in the figure denotes a V-shaped stud attached to the outer tube 24 to support the irregular refractory material 22.

In this gas blowing lance pipe, however, the gas discharge ports 28, 29 are oriented with their lower ends facing the molten metal.
The gas is blown into the molten finance by discharging the gas from.

[0005]

However, in the above-mentioned conventional gas injection lance pipe, since the lower end portion of the gas discharge port directed to the molten metal is exposed to a very high temperature, the lower end core pipe and The refractory covering the outer periphery of the core tube was damaged, and eventually the core tube was melted and damaged, resulting in a very short service life.

In particular, in an oxygen-blown lance pipe used for UT treatment of molten steel temperature in a ladle for steelmaking (treatment for the purpose of raising the temperature of molten steel), the temperature rises sharply due to the discharge of oxygen gas, so this tendency tends to occur. It has become noticeable.

Therefore, an object of the present invention is to provide a gas injection lance pipe which can prevent damage in the vicinity of the gas discharge port and can greatly improve the service life.

[0008]

In order to solve the above-mentioned problems, in the gas injection lance pipe of the present invention, a cylindrical refractory brick excellent in corrosion resistance is detachably fitted to the outer periphery of the gas discharge port of the core tube. The refractory bricks and a part of the core tube of the refractory brick are covered with an irregular refractory material.

[0009]

In the above means, it is possible to replace the refractory brick covering the outer periphery of the core tube near the gas discharge port.

As refractory bricks, MgO, Cr ₂ O ₃
As the main component (for example, MgO 15 to 80% by weight, Cr ₂ O ₃
5 to 85% by weight) fired or unfired MgO-C
r ₂ O ₃ is preferred.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are a half sectional front view and a lateral sectional view of a main portion of a gas blowing lance pipe according to an embodiment of the present invention.

This gas blowing lance pipe is an oxygen blowing lance pipe used for UT treatment of molten steel temperature in a ladle for steel making, and its metal core tube 1 is an inner tube 2 and an outer tube 2 having different outer diameters. It has a double tube structure in which the tube 3 and the tube 3 are concentrically provided by interposing a plurality of gap spacers 4. Core tube 1
A flange 5 for connecting this lance pipe to a lifting device such as a hoist (not shown) is opened at one end (upper end in FIG. 1) of the inner pipe 2 so that one end of the inner pipe 2 serves as a gas inlet 6 for oxygen gas. In addition, the inner tube 2 and the outer tube 3 are attached so as to close the space between the inner tube 2 and the outer tube 3 so that the inert gas for cooling can be contained therein. A small-diameter short tube serving as a gas inlet 7 for gas is provided.

On the other hand, the other end portion (the lower end portion in FIG. 1) of the core tube 1 serving as the gas discharge ports 8 and 9 of the above respective gases.
A cylindrical refractory brick 10 having excellent corrosion resistance is removably fitted in the. The refractory brick 10 is 70% by weight of MgO and 10% by weight of Cr ₂ O ₃ , and is a MgO-Cr ₂ O ₃ brick which is burned at an ultrahigh temperature (1800 ° C.), and is slightly smaller than the outer diameter of the outer tube 3. In addition to having a large inner diameter, a locking circumferential groove 11 is formed on the outer circumference of one end portion thereof, as described in detail in FIG. The refractory brick 10 fitted to the outer tube 3 of the core tube 1 has a plurality of crank-shaped holders 12 mounted on the outer circumference of the outer tube 3 and spaced apart in the circumferential direction. The core tube 1 is mounted by being engaged with 11. One end of the refractory brick 10 thus fitted to the core tube 1 and most of the core tube 1 (7 to 8 of the total length).
The outer circumference of the split is covered with a castable refractory material, a plastic refractory material, or the like to have a required thickness.

In FIG. 1, reference numeral 15 is a V-shaped stud attached to the outer tube 3 and the holder 12 for supporting the irregular refractory material 14.

In the oxygen blowing lance pipe having the above structure, the refractory brick 10 is fitted to the lower end of the outer tube 3 of the core tube 1 and mounted by the holder 12, and then the refractory brick 10 and the periphery of the core tube 1 are fitted. The mold is placed in the mold, and the irregular refractory material 14 is poured between the mold and one end of the refractory brick 10 and most of the core tube 1 to be solidified. 10 new refractory bricks 1
When exchanging with 0, the irregular refractory material 14 covering the refractory brick 10 is removed, the holder 12 is bent outward to release the engagement with the locking circumferential groove 11, and the refractory brick 10 is pulled out downward. And then remove the new refractory brick 10 to the outer tube 3
Then, the new refractory brick 10 is attached to the outer periphery of the refractory brick 10, and the irregular refractory material 14 is attached to the outer periphery of one end of the new refractory brick 10 for restoration.

In the above embodiment, the core tube 1
Since the refractory brick 10 fitted to the outer tube 3 of 3 is mounted,
The case where the locking projection 13 of the holder 12 is engaged with the locking circumferential groove 11 of the refractory brick 10 has been described, but the invention is not limited to this. For example, as shown in FIG. Metal locking ring 16 in the circumferential groove 11
May be fitted in advance, and the lower end of the holder 121 may be fixed to the locking ring 16 of the refractory brick 101 fitted to the outer tube 3 of the core tube 1 by spot welding or the like. In this case, when replacing the damaged refractory brick 101, the lower end of the holder 121 is melted and the refractory brick 101 is removed.

[0018]

As described above, according to the gas blowing lance pipe of the present invention, it is possible to replace the refractory brick covering the outer periphery of the core pipe near the gas discharge port, which is the most damaged. Combined with the fact that the heat resistance and the corrosion resistance are superior to those of the amorphous refractory, the service life can be greatly improved as compared with the conventional one.

[Brief description of drawings]

FIG. 1 is a front view of a gas injection lance pipe according to an embodiment of the present invention in half section.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a perspective view showing a mounted state of a refractory brick by a holder.

FIG. 4 is a perspective view showing another mounting state of the refractory brick by the holder.

FIG. 5 is a front view of a half cross section of a conventional gas blowing lance pipe.

FIG. 6 is a bottom view of a conventional gas blowing lance pipe.

[Explanation of symbols]

 1 Core Tube 2 Inner Tube 3 Outer Tube 8 Gas Discharge Port 9 Gas Discharge Port 10 Refractory Brick 11 Locking Circumferential Groove 12 Holder 13 Locking Protrusion 14 Amorphous Refractory 16 Locking Ring 101 Fireproof Brick 121 Holder

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshikazu Kubo 1815 Minato, Wakayama, Wakayama Sumitomo Metal Industries, Ltd. Wakayama Works (72) Inventor Keita Nakagawa 1815, Minato, Wakayama, Wakayama Sumitomo Metal Industries Ltd. Company Wakayama Steel Works

Claims (1)

[Claims] 1. A cylindrical refractory brick having excellent corrosion resistance is detachably fitted to the outer periphery of the gas discharge port of the core tube, and a part of the refractory brick and the outer periphery of most of the core tube are not attached. A gas injection lance pipe covered with a regular refractory.