JPH0369965B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to intermediate repair of the bottom of a non-separated type top-bottom blowing or bottom-blowing converter.

In general, in top-bottom blowing or bottom-blowing converters, reactive gases are injected from the bottom of the furnace, which causes large local wear at the bottom of the furnace due to strong stirring of high-temperature molten steel and repeated heating and cooling of the lining refractory. It is well known to do so. Localized wear that occurs around the bottom tuyeres of such top-bottom blowing or bottom-blowing converters (hereinafter simply referred to as bottom-blowing converters) causes uneven wear on the bottom and walls of the furnace. Although the furnace wall is still usable, local wear and tear at the bottom of the furnace determines whether the furnace should be shut down.
Situations have occurred that significantly shorten the life of the furnace.
Conventionally, as a countermeasure to this problem, a method of replacing the furnace bottom by creating a separate structure for the furnace bottom has become common. However, this method requires a large amount of investment in equipment for attaching and detaching the bottom of the furnace, and is also difficult in terms of factory layout. In addition, since the remaining bricks are discarded for replacement, the effective utilization rate of furnace materials decreases, leading to a rise in the cost of furnace materials, and there are many difficulties in sealing the joints during installation and removal, which reduces reliability. It has disadvantages such as poor quality.

On the other hand, in fixed furnace bottom structures, as an intermediate repair around the tuyere, a method of externally replacing the tuyere bricks is generally adopted. However, since this method only replaces the tuyere bricks, it is impossible to repair the hearth bricks around the tuyeres. Therefore, as methods for repairing the furnace bottom around the tuyere, spraying repair, press-fitting repair, baking repair, coating repair, etc. have been proposed, but all of them are difficult to repair due to high-temperature strong agitation and thermal shock around the tuyere. However, it is not effective enough, and it has not been possible to balance the lifespan of the furnace wall and the furnace bottom.
In addition, as a means to ensure a lifespan balance between the furnace wall and the furnace bottom, a furnace wall structure that matches the lifespan of the furnace bottom can be considered, but since this conversely shortens the average furnace life, it reduces furnace material costs and production. This is a poor and not an effective method. As described above, the establishment of technology for intermediate repair of the bottom of bottom-blown converters has become a major technical issue that will govern the future of bottom-blown converters.

The present invention can repair the hearth bottom with high reliability, thereby significantly reducing the cost of furnace materials, and sufficiently ensure the safety of the repair work, which are the disadvantages of the conventional method as described above. This is because after the furnace body has been cooled, a repair tower is inserted and the worn parts of the hearth bottom are stripped and removed, and then the peeled off parts are repaired with brickwork, resulting in an extremely effective hearth bottom. This is an intermediate repair method for the bottom of a non-separable converter furnace.

The method of the present invention will be described below.

First, the wear of the bottom blowing converter progresses approximately twice as much around the bottom tuyere as shown in the melting line 1a in Fig. 1 (described later), compared to the side wall.
The furnace will shut down due to wear around the bottom tuyeres. For this reason, by performing an intermediate repair by replacing the bricks on the bottom of the furnace bottom when the wear and tear around the tuyeres at the bottom has progressed considerably, the bottom blowing converter can be used until the side wall bricks are worn out. Ru.

This intermediate repair of the area around the bottom tuyeres is carried out by inserting a repair tower into the furnace body that can ensure the safety of workers inside the furnace and a sufficiently spacious working area after the furnace body has been cooled.
Next, the worn parts around the tuyeres are stripped off and the stripped parts are repaired with brickwork. When repairing this brickwork, it is necessary to make the length of the remaining end face bricks at least 50% of the length of the new construction bricks in order to prevent the new construction bricks from falling off when the temperature rises.

Next, one embodiment of the method of the present invention will be described in detail based on the drawings.

Fig. 1 shows a cross-sectional view when a repair tower is installed in a bottom blowing converter, Fig. 2 shows a partially enlarged view of the bottom repair part shown in Fig. 1, and Fig. 3 shows a Fig. 4 is an enlarged view of the bottom of the furnace shown in the figure after repair;
An enlarged view of the brickwork section is shown.

First, the furnace body 1 when the final blowing work is completed is as follows:
Because it is quite high temperature, it should be left to cool naturally or
The furnace body 1 is cooled by blowing cold air or the like. After that, a repair tower 3 which is a hollow rectangular cylindrical body, for example,
is inserted into the furnace body using a lifting device (not shown) such as a crane, and is also fitted into the holding cart 2. After the repair tower 3 is inserted into the furnace, the skirt portion 4 at the lower end of the repair tower 3 is expanded by, for example, a chain and winch (not shown) to secure a working space at the furnace bottom 5. The upper part and surrounding area are surrounded by, for example, iron plates to ensure sufficient safety against falling objects. Furthermore, a worker passes through the work floor 7, transfers to the holding cart 2, descends the ladder 6 fixed to the repair tower 3, and peels off the worn parts around the hearth bottom tuyeres using, for example, an air pickle. Remove. After removing the worn parts around the tuyere, the blow nozzle 9 is fixed to the shell 8 of the furnace bottom 5 by, for example, screwing, and the sleeve is inserted into the blow nozzle 9 from the inside of the furnace body 1. The tuyere brick 11 into which the brick 10 has been fitted is inserted and fixed. After the tuyere bricks 11 are fixed, permanent bricks 1 are placed in the area (gap area) where the bricks of the furnace bottom 5 have been peeled off and removed.
2 are stacked in three tiers, and a new hearth brick 14 is constructed. When constructing the new hearth bricks 14, it is necessary to take into account the slope of the brick end faces 13a of the remaining bricks 13 and construct them evenly so that one side does not become reversed. Remaining end face brick 13a and new hearth brick 14
The boundary bricks are three adjustment bricks 14a,
14b and 14c. This is because arch bricks are built from the middle, which makes it impossible to construct bricks from the outside as usual, and with reverse auction bricks, bidding is impossible, so the new hearth bricks 14 may fall off. This is to prevent this. This completes the reloading of the bricks, but since there is a dimensional difference between the new hearth bricks 14 and the remaining bricks, the protruding parts of the new hearth bricks 14 will peel off due to spalling during heating, so the remaining bricks 13 Place the monolithic refractory 15 on the operating surface at the height of the new brick 14.
Complete the repair by stamping.

In addition, all of these new hearth bottom bricks 14 have slightly larger side widths of the iron skin, for example, when shown as adjusted bricks, the inner side width of the hearth is A.
and the steel skin siding A' is A<A', C<C',
The adjustment bricks in the middle part have B=B', and the new hearth bottom bricks 14 as described above are held in a competitive structure as a whole. Furthermore, as a result of applying the intermediate repair method according to the present invention to a 300 ^T top-bottom blowing converter, the life of a conventional furnace was extended by 30%, resulting in a significant reduction in the cost of furnace materials. Ta.

As described above, according to the repair method of the present invention, a reliable lifespan can be obtained because the replacement part is made of bricks of the same quality as when it was constructed. In addition, the boundary between the old and new bricks is completely made of bricks, and it is a regular piece of construction with a high degree of reliability. Furthermore, by adjusting the length of the reloading bricks, it is possible to completely adjust the life balance between the side walls and the bottom of the furnace, increasing the lifespan of the bottom blowing converter and significantly reducing the cost of furnace materials. This is an extremely effective repair method that can ensure the safety of workers inside the reactor and can be widely applied to non-separated converters.

[Brief explanation of drawings]

Fig. 1 shows a cross-sectional view when a repair tower is installed in a bottom-blowing converter, Fig. 2 shows a partially enlarged view of the bottom repair part shown in Fig. 1, and Fig. 3 shows a cross-sectional view of the repair tower shown in Fig. Fig. 4 shows an enlarged view of the furnace bottom after repair, and Fig. 4 shows a partially enlarged view of the repaired brickwork part. 1...furnace body, 2...holding cart, 3...repair tower, 4...skirt section, 5...furnace bottom, 6...ladder, 7...work floor, 8...iron shell, 9... Blowing nozzle, 10... Sleeve brick, 11... Tuyere brick, 12... Permanent brick, 13... Remaining brick, 13a... End face of remaining brick, 14... New hearth brick, 14a, 14b, 14c... Adjustment brick, 15...Unshaped refractory.

Claims (1)

[Claims] 1 In intermediate repair of the hearth bottom of a non-separated hearth converter,
After cooling the furnace body, a repair tower, which is a hollow cylindrical body and has an expandable skirt portion at the lower end, is inserted into the furnace body, and the refractory material in the worn part of the furnace bottom is stripped and removed. An intermediate repair method for a converter bottom of a non-separable type converter, characterized in that the peeled-off portion is then repaired by bricklaying.