JPS5918444B2 - Manufacturing method for furnace nozzles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nozzle for refining metal by blowing oxygen gas into a melting furnace such as a converter, and a method for manufacturing the nozzle.

Conventionally, a nozzle 1 for blowing oxygen into a converter is formed into a double pipe, as shown in FIG. is fed under pressure to cool the inner tube 2.

The nozzle 1 supports the inner circumferential surface of the outer tube 3 with a large number of protrusions 21 formed by spot filling the outer circumferential surface of the inner tube 2, thereby keeping the inner and outer tubes 2 and 3 concentric.

However, applying spot embossment to the outer peripheral surface of the inner tube 2 requires skill and effort, and the spot embossment must be polished to make the heights of the protrusions 21 uniform, which does not improve production efficiency.

In addition, the protrusion part of the inner tube cools more poorly than other parts, and the tip of the nozzle melts and wears out before the inner wall of the furnace thins, necessitating frequent replacement of the nozzle. .

In view of the above circumstances, the present invention provides a method for manufacturing a furnace nozzle that can uniformly cool the inner tube and solve the above problems at once by interposing a metal wire between the inner tube and the outer tube. With the goal.

The present invention will be specifically described below based on embodiments shown in the drawings.

FIG. 1 shows a situation in which a nozzle 1 manufactured by the method according to the invention is installed by penetrating a side wall 91 of a converter 9.

In the nozzle 1, the inner tube 2, which is slightly longer than the outer tube, is fitted concentrically with the tips of the outer tube 3 having a length corresponding to the thickness of the side wall 91, so that the inner circumferential surface of the outer tube 3 and the outer circumference of the inner tube 2 are aligned. A circulation space 4 is formed between the two surfaces.

A spirally wound metal wire 7 is disposed close to the outer wall of the furnace in the circulation space 4 and is closely connected to the inner circumferential surface of the outer tube 3 and the outer circumferential surface of the inner tube 2. The circulation space 4 between the two is composed of a spiral space 5 formed by the spiral metal wire 7 and a straight annular space 6 continuous with the space 5.

The total length of the spiral space 5, that is, the length 20 of the portion around which the metal wire 7 is wound, is made approximately equal to the thickness of the side wall 91 of the furnace when it is thinned from the inner surface 93 side and reduced to the usable limit thickness.

Next, a method for manufacturing the above nozzle 1 will be explained.

As shown in FIG. 2, a metal wire 7 is wound spirally around the proximal end of the outer circumference of the inner tube 2.

In this example, the metal wire has a wire diameter of 1.6 mm and a helical pitch of 71 mm.
is approximately 2Qi211.

An auxiliary metal wire 8 having the same thickness as the metal wire 7 is wound around the outer periphery of the tip of the inner tube 2 a plurality of times at tighter pitches.

Next, an outer tube having an inner diameter equal to or equal to the winding diameter of the spiral metal wire 7 is placed over the metal wires 7 and 8, and in this state, the outer tube 3 is passed through a drawing die (not shown) and subjected to a drawing process. , the entire length of the outer tube 3 or the portion of the helical space 5 is equally reduced in diameter.

Thereby, the metal wire 7 and the auxiliary metal wire 8 are brought into close contact with the inner circumferential surface of the outer tube 3 and the outer circumferential surface of the inner tube 2, so that the inner and outer tubes 2 and 3 can be fixed.

Metal wires 7 and 8 of equal thickness are wrapped around both sides of the inner tube 2 to prevent the inner and outer tubes from becoming misaligned and to reduce the diameter of the outer tube 3.
The inner and outer tubes are aligned concentrically.

Next, the tips of the inner and outer tubes 2 and 3 on the auxiliary metal wire 8 are cut off (the positions indicated by the two-dot chain lines in FIG. 2).

As a result, the inner and outer tubes 2 and 3 are aligned concentrically, and the nozzle 1 has a flow space 4 corresponding to the wire diameter of the metal wire 7 between the outer circumferential surface of the inner tube 2 and the inner circumferential surface of the outer tube 3. Easy to form.

The circulation space 4 consists of two sections, namely, a spiral space 5 in which the metal wire 7 is wound, and an annular space 6 that communicates with the spiral space 5 and opens to the tip of the nozzle 1.
It is.

The nozzle 1 is fitted into a hole 92 made in the side wall 91 of the converter 9 as shown in FIG. Oxygen is blown into the furnace from the oxygen pressure inlet 11 through the inner tube 2 to burn impurities in the hot water and obtain hot water with high purity.

The cooling inert gas blown out from the inert gas pressure feeding mouthpiece 12 is sent into the furnace through the circulation space 4 between the inner tube 2 and the outer tube 3, and cools the inner and outer tubes 2 and 3 during this time. do.

Since the circulation space 4 is formed into a spiral space 5 on the base 11 side and a straight annular space 6 on the tip side, the inert gas becomes a swirling flow by passing through the spiral space 5 and flows through the annular space 6. However, since there are no protrusions on the outer circumferential surface of the inner tube 2 above the annular space 6 that would obstruct the passage of the inert gas flow, the inner tube 2 is uniformly cooled all around.

As a result, the speed at which the tip of the inner tube 2 melts and wears out due to the high heat of the furnace approximately matches the speed at which the inner surface 93 of the side wall 91 of the converter is thinned due to the high heat of the furnace, and the life of the nozzle can be extended. be.

In addition, the total length of the helical space of the nozzle approximately corresponds to the side wall thickness when the furnace is thinned and reduced to the usable limit thickness. , so the length of this spiral space does not change until the end.

FIG. 4 shows an embodiment in which the inner tube 2 is welded and fixed to both the oxygen pressure feed mouthpiece 11 and the inert gas pressure feed mouthpiece 12.

As before, the tip of the inner tube is fitted into the oxygen pressure feeding cap 11 and welded 13, and the tip of the inner tube slightly closer to the outer tube is fitted into the circular plate 15 with the circulation hole 14 fixed to the inert gas pressure feeding cap 12 and welded. 16 fixed.

By fixing the inner tube 2 to both caps 11 and 12 as described above, the inner tube 2 is more strongly fixed to the caps.

In this embodiment, a metal wire and an auxiliary metal wire 8 are provided on the outer periphery of the inner tube 2.
is wound spirally and then covered with the outer tube 3; however, the invention is not limited to this; a spirally wound metal wire is attached to the inner surface of the outer tube, and the inner tube 2 is inserted into the outer tube 3. Of course, you can fit it in.

. As described above, the present invention involves wrapping a metal wire multiple times around the outer circumference of the inner tube inside the furnace or the inner circumference of the outer tube inside the furnace to be cut in a subsequent process, and applying a drawing process to the outer tube to shrink the outer tube. For diameter, inside,
Misalignment of the outer tube is prevented, and the annular space on the tip side of the completed nozzle has a uniform width, so that the cooling effect on the nozzle is uniform over the entire circumference of the nozzle.

[Brief explanation of drawings]

Figure 1 is a sectional view showing how the nozzle is used, Figure 2 is a sectional view of the inner tube covered with the outer tube, Figure 3 is a sectional view of the conventional example, and Figure 4 is the connection between the nozzle and the inner tube. It is a sectional view showing another example of a state. 1...nozzle, 2...inner tube, 3...
... Outer tube, 4 ... Space, 4 ... Spiral space, 6 ... Annular space, 7 ... Metal wire.

Claims (1)

[Claims] 1. A metal wire is attached to the outer surface of one end of the inner tube or the inner surface of one end of the outer tube in a corresponding range according to the thickness of the side wall of the furnace when the thickness is reduced to the usable limit thickness. A step of winding an auxiliary metal wire of the same thickness as the metal wire multiple times at a tight pitch around the outer surface of the other end of the inner tube or the inner surface of the other end of the outer tube. The process of fitting the inner and outer tubes together; the process of drawing the outer tube to reduce its diameter; and fixing the inner and outer tubes by bringing metal wires into close contact with the inner surface of the outer tube and the outer surface of the inner tube; auxiliary metal A method for manufacturing a furnace nozzle that involves a series of steps of cutting off the other ends of the inner and outer tubes around which the wire is wound.