JP6089546B2 - Repair method for converter steel outlet - Google Patents

Description

  The present invention relates to a repair method for renewing a refractory sleeve attached to a steel outlet for discharging molten steel in a converter to the outside of the furnace, and fixing the sleeve to the steel outlet. In particular, the present invention relates to a method of fixing a tube having a flange at its end inserted and held in a sleeve to a converter steel outlet.

  For example, a converter is used when steelmaking is performed by refining hot metal from a blast furnace at an ironworks. As shown in FIG. 1, the converter 1 has a steel outlet 3 for discharging molten steel 2 refined in the furnace toward, for example, a casting pan 20 outside the furnace. A sleeve 4 made of a hollow cylindrical refractory is inserted into the steel outlet 3 to protect the steel outlet 3, and the molten steel 2 is discharged from the through hole 4 a of the sleeve 4 to the outside of the furnace. Therefore, the inner peripheral surface of the sleeve 4 of the steel outlet 3 becomes a passage for the molten steel 2, and as a result, the erosion gradually proceeds. If this erosion progresses to some extent, eddy currents are likely to occur during steel output, and as a result, the slag 5 is caught in the molten steel to be discharged and the quality of the molten steel is degraded. Therefore, it is necessary to update the sleeve 4 when the wear of the sleeve 4 has progressed.

The sleeve 4 is renewed by removing a worn sleeve in the hot state, and then inserting a new refractory sleeve through the steel outlet and filling the gap between the sleeve and the furnace body with the irregular refractory. The method is widely practiced.
That is, as shown in FIG. 2 (a), the converter 1 is tilted so that the steel outlet 3 is set in front of the drilling machine 11, and the wear sleeve 40 remaining inside the steel outlet 3 is shown in FIG. As shown in FIG. Next, as shown in FIG. 2 (c), a new sleeve 4 is inserted into the steel outlet 3, and as shown in FIG. 2 (d), the sleeve 4 is placed inside the steel outlet 3, for example, a furnace. It is fixed to the body side by welding w (via a flange F of a presser foot which will be described later). At that time, if there is a gap between the steel outlet 3 and the flange F, it is necessary to bond with a clay-like amorphous refractory r. Finally, as shown in FIG. 3, the amorphous refractory 6 is poured into the gap between the steel outlet 3 and the sleeve 4 from the inside of the converter 1, and the sleeve 4 is finally fixed inside the steel outlet 3. .

  Here, the sleeve 4 is attached to, for example, a sleeve brick pressing hardware described in Patent Document 1, and is inserted into the steel outlet 3 integrally with the hardware. This sleeve brick retainer is a steel pipe that has a flange-like member at the end in order to fix the sleeve made of refractory to the furnace body and to prevent leakage of the irregular refractory to be filled. Patent Document 1 also proposes a method of fixing the steel pipe inserted into the sleeve and fixing the sleeve to the steel pipe to the steel outlet of the converter.

  Patent Document 1 discloses a method of welding and fixing a flange portion of a sleeve brick retainer to an existing furnace body side flange around a converter steel outlet through a metal fitting having a movable part.

JP 7-234078

  In the method described in Patent Document 1, it is necessary to perform welding work in a high temperature working environment, and welding and fusing of metal fittings are repeatedly performed on the furnace body side flange of the converter steel outlet, or in a high temperature oxidation environment Since the surface properties are rough due to exposure, welding to the furnace body flange has been a difficult task. Therefore, problems to be solved remain, such as requiring a long time for the work and sometimes lacking the strength of the weld.

  Accordingly, an object of the present invention is to propose a method for securely and simply fixing a new sleeve to a steel outlet without using the above-described welding.

The inventors diligently studied a way to solve the above-mentioned problems, and fixed the flange to the furnace body side with a structure in which a rod-shaped member is passed in the radial direction of the flange in the sleeve holder to fix the bar. It has been found that this can be an extremely effective measure, and the present invention has been completed.
That is, the gist configuration of the present invention is as follows.
(1) When renewing a refractory sleeve attached to a steel outlet for discharging molten steel inside the converter to the outside of the furnace, insert a new sleeve into the pipe having a flange at one end. Insert the retained sleeve holder from the other end of the pipe into the steel outlet from which the old sleeve has been removed, and insert the rod-like member through at least a pair of receivers provided around the steel outlet, A method of repairing a converter steel outlet by pressing the flange against the converter furnace body with the rod-shaped member and fixing the sleeve holder to the steel outlet.

(2) A pressing member that can be advanced and retracted toward the flange is attached to the rod-shaped member, and after the rod-shaped member is inserted into the receiver, the pressing member is moved toward the flange, and the pressing material is moved to the flange. The method for repairing a converter steel outlet according to claim 1, wherein the flange is pressed between the rod-shaped member and the flange and pressed against the converter body side.

  According to the present invention, work such as welding in a high-temperature work environment is eliminated, and the physical load on the worker is remarkably reduced. In addition, since the work of welding and fusing of the flange is eliminated, the flatness of the flange is improved and the gap between the flanges is reduced. The work of painting things is no longer necessary. These conventional operations have been replaced with operations that securely press and fix the flange to the steel outlet through the mechanical structure, greatly reducing the time required for hot repair of the converter steel outlet hole. As a result, the converter operation rate can be improved.

It is a figure which shows the structure of the steel outlet of a converter. It is a figure which shows the repair procedure of the steel outlet of a converter. It is a figure which shows the repair procedure of the steel outlet of a converter. It is a figure which shows the holder of a sleeve. It is a figure which shows the fixing structure of the holder flange according to this invention. It is a figure which shows another fixing structure of the holder flange according to this invention. It is a figure which shows another fixing structure of the holder flange according to this invention.

Next, the repair method of the present invention will be described in detail with reference to the drawings.
In addition, the procedure for removing the existing old sleeve worn with use of the converter is the same as that shown in FIGS. 2 (a) to 2 (b), and a description thereof will be omitted. Therefore, it demonstrates from the operation | work step which inserts the new sleeve 4 in the steel outlet 3 shown after FIG.2 (c).
Here, the new sleeve 4 is usually attached to a holder. That is, as shown in FIG. 4A, for example, a cylindrical sleeve 4 made of a refractory (brick) has a flange 7a having a diameter sufficiently larger than the outer diameter of the sleeve 4 and the flange 7a fixed to the tip. It is attached to a sleeve holder 7 comprising a tube 7b.
When attaching the sleeve 4 to the sleeve holder 7, when the amorphous refractory 6 is poured into the gap between the refractory brick of the steel outlet 3 and the sleeve 4 as shown in FIG. In order to prevent leakage to the outside of the furnace along the flange 7a, a cushioning material 7c is provided between the flange 7a and the sleeve 4 as shown in FIG. It is preferable to arrange. As the buffer material 7c, for example, a ceramic fiber, which is an inorganic refractory fiber having a basic composition of alumina (Al ₂ O ₃ ) and silica (SiO ₂ ), is suitable. Similarly, it is preferable to cover with an iron plate 7d or the like so that the amorphous refractory does not enter between the tube 7b and the sleeve 4 when the amorphous refractory is poured. Further, the sleeve 4 may be fixed to the inserted tube 7b and / or the flange 7a with an inorganic adhesive or the like.

  The sleeve 4 integrated with the sleeve holder 7 described above is inserted into the steel outlet 3 from the outside of the converter 1 as shown in FIG. At that time, the holder 7 is inserted deeply into the steel outlet 3 until the flange 7 a of the sleeve holder 7 comes into contact with the furnace body of the converter 1.

  Next, as shown in FIG. 5, the flange 7a of the sleeve holder 7 is provided between the receivers 8a and 8b that are bent in an L shape and open upward in the furnace body of the converter 1. The fixing bar 9 which is a rod-shaped member having a length straddling in the direction is stretched over and the tacking is performed. In the illustrated example, two pairs of receivers 8a and 8b are provided, a fixing bar 9 is spanned between each pair of receivers 8a and 8b, and the flange 7a is directed to the furnace body side of the converter 1 by the two fixing bars 9. Press to fix to the furnace body. Note that the number of fixing bars 9 is not limited to two, and may be one or three or more. In any case, when the diameter of the flange 7a is R as shown in FIG. 5, it is preferable to arrange the fixing bar 9 in a region from the center of the flange 7a to 2 / 3R.

  Here, when the fixing bar 9 is inserted into the receiving tools 8a and 8b, the fixing bar 9 is fixed inside the receiving tools 8a and 8b without providing a gap between the inner surface of the receiving tools 8a and 8b and the fixing bar 9. If the bar 9 can be disposed, the flange 7a can be firmly pressed toward the furnace body side of the converter 1 and securely fixed to the furnace body. That is, if the surface of the flange 7a is not rough due to welding marks or solidification marks of molten steel droplets, the fixing bar 9 is connected to the flange 7a without providing a gap between the inner surfaces of the receiving tools 8a and 8b and the fixing bar 9. The fixing bar 9 can be spanned between the receivers 8a and 8b in close contact with each other, and the flange 7a can be reliably fixed. As described above, the flange 7a is fixed by placing the fixing bar 9 inside the receivers 8a and 8b without gaps, and a typical example is when a new sleeve holder 7 is attached.

By the way, the sleeve holder 7 is not changed as frequently as the replacement frequency of the sleeve, but is usually used for a long time. Therefore, the surface of the flange 7a is often rough due to solidified traces of molten steel droplets. In this case, as shown in the enlarged view of FIG. 5 , the receiving parts are fixed to the inner surfaces of the receiving parts 8a and 8b. It is necessary to provide a gap with the bar 9. This is because the rough raised portion of the surface of the flange 7a keeps the fixing bar 9 away from the ground surface of the flange 7a, and therefore it is necessary to insert the fixing bar 9 into the receiving tools 8a and 8b through a gap corresponding to the raised portion. Because there is.

On the other hand, if there is a gap between the inner side surfaces of the receivers 8a and 8b and the fixing bar, it becomes difficult to bring the fixing bar 9 into close contact with the flange 7a. As a result, the pressing force of the flange 7a on the furnace body side May be insufficient.
Therefore, as shown in FIG. 6, bolts 10 a and 10 b as pressing members are attached to the flanges 7 a so as to be able to advance and retract at positions corresponding to the vicinity of the periphery of the flanges 7 a of the respective fixing bars 9. After the fixing bar 9 is accommodated in the receivers 8a and 8b, the bolts 10a and 10b are screwed in to advance until the bolts abut against the flange 7a. A total of four bolts 10a and 10b for each fixing bar 9 are screwed in, and each bolt is firmly hit against the flange 7a, and further, the bolts are screwed until the fixing bar 9 comes into contact with the inner side of the receivers 8a and 8b. In this state, the bolts 10a and 10b are interposed between the fixing bar 9 and the flange 7a constrained inside the receivers 8a and 8b. As a result, the bolts 10a and 10b are strongly pressed against the flange 7a. Accordingly, the bolt can be strongly pressed against the flange 7a according to the tightening force of the bolts 10a and 10b, and the flange 7a is securely fixed to the furnace body side.

  Thereafter, in accordance with what is shown in FIG. 3, the amorphous refractory 6 is poured into the gap between the steel outlet 3 and the sleeve 4 from the inside of the converter 1, and finally the sleeve 4 is strongly strengthened inside the steel outlet 3. Once fixed, the hot repair of the converter outlet is completed.

In addition, since the periphery of the steel outlet 3 is always placed in a harsh environment such as receiving splashes of molten steel, the above-mentioned receptacle fixed to the furnace body around the steel outlet 3 by welding or the like. 8a and 8b may fall off. In that case, it is possible to perform welding and reattach the receiver, but it is also advantageous to use a detachable receiver 8c shown in FIG.
That is, the receiver 8c has a cross-sectional shape in which the channel portion and the angle portion are combined, and as shown in FIG. 7, the existing flange portion 1a provided around the steel outlet 3 of the converter 1 and the furnace body By hooking one end of the channel portion into the gap, and screwing the bolt 8d into the flange portion 1a, the flange portion 1a can be sandwiched between the channel portions and fixed to the flange portion 1a. As described above, the receiving portion 8c fixed to the flange portion 1a functions as a receiving portion of the fixing bar 9 in the same angle portion as the receiving portions 8a and 8b described above.

[Invention Example]
Using a magnesia carbon brick sleeve having an inner diameter of 220 to 250 mm, a length of 1250 to 1600 mm, and a weight of 178 to 226 kg, the repair work for renewing the sleeve at the outlet of the top bottom blowing converter of the heat size 360 t is as follows. It implemented in procedure (1)-(4). In addition, a sleeve holder having a steel flange with an outer diameter of 330 mm was inserted into and fixed to the new sleeve according to the position shown in FIG.

(1) First, after removing the metal attached to the steel outlet, the steel outlet was drilled to remove the intrusion part of the metal and the slag, and the refractory serving as the base material was exposed (work Time: 20 minutes).
(2) A sleeve presser fitting that is inserted into the new sleeve and holds it is inserted from the converter steel outlet and positioned (working time: 5 minutes).
(3) In accordance with what is shown in FIG. 6, two fixing bars capable of adjusting the protruding length of the bolt to the flange side are hung over two places each of the receiving tools installed at the converter steel outlet, After mounting the sleeve so that it crosses the flange of the sleeve presser foot, increase the protrusion of the bolt by screwing in the bolt, and press the bolt against the flange of the sleeve presser foot to connect the flange to the flange of the converter steel outlet. Press to fix (working time: 2 minutes).
(4) Tilt the converter so that the steel outlet faces downward, spray and pour an indefinite refractory from the inside of the furnace, fill the gap between the sleeve and the furnace body, and then use the heat held by the furnace body Dried (working time: 23 minutes).

[Comparative example]
As a comparison, the sleeve presser flange was welded to the furnace body side, and an irregular refractory was applied to the joint between the flanges on the outside of the furnace (working time: more than 20 minutes). After that, the converter is tilted so that the steel outlet is facing downward, and the refractory is sprayed from the inside of the furnace and poured into the gap between the sleeve and the furnace body. Dried by heat.

Comparing the working time between the inventive example and the comparative example, the work of the above (3) in the inventive example was completed in 2 minutes, but the work in the comparative example corresponding to this work was over 20 minutes. According to the invention, the working time is reduced by about 20 minutes per time. This makes it possible to increase the converter operation time by about 120 minutes / month. Furthermore, it was possible to eradicate the heat stroke of workers in this work.

1 Converter 2 Molten steel 3 Steel outlet 4 Sleeve 5 Slag 6 Amorphous refractory 6
7 Sleeve holder 7a Flange 7b Tubes 8a, 8b, 8c Receiver 9 Fixing bar 10a, 10b Bolt

Claims (2)

When renewing a refractory sleeve attached to a steel outlet for discharging molten steel in the converter to the outside of the furnace, a new sleeve is attached to the pipe having a flange at one end , and the sleeve and the flange. A sleeve holder that is inserted between the sleeve and the gap between the sleeve and the pipe with an iron plate, and holds the other end of the pipe against the steel outlet from which the old sleeve has been removed. The channel portion is inserted into the gap between the existing flange portion and the converter main body around the steel outlet, and is inserted from the side and has at least a pair of receiving parts having a channel portion and an angle portion around the steel outlet. with hooked end, by screwing the bolt to the flange portion, the flange portion is fixed to the flange portion pinching said channel portion, through insert the rod-like member in the receptacle, the rod-shaped member A method of repairing a BOF tapping nozzle, characterized in that for fixing the sleeve holder in the tapping nozzle is pressed against the flange on the converter furnace side.   A pressing member capable of advancing and retreating toward the flange is attached to the rod-shaped member, and after inserting the rod-shaped member into the receiving member, the pressing material is moved toward the flange, and the pressing member is moved to the rod-shaped member. The method for repairing a converter steel outlet according to claim 1, wherein the flange is pressed between the flange and the flange against the converter body.

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