JP3724134B2 - Furnace split type converter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure of a converter, and relates to a furnace body division type converter in which a furnace body can be separated at a plurality of positions in the vertical direction.
[0002]
[Prior art]
Converters that melt metals, especially steel and iron alloys, cause an oxidation reaction by supplying an oxidizing gas such as oxygen to a molten metal held in the furnace (hereinafter referred to as molten metal). Exposed to high temperatures. In recent years, CO gas generated from the molten metal during refining is so-called secondary combustion in the converter, and the combustion heat is recovered in the molten metal so that the energy cost required for refining is reduced. became.
[0003]
This secondary combustion occurs when oxygen gas is blown onto the molten metal surface via an upper blowing lance, so that it usually occurs in the furnace space corresponding to the upper part of the furnace body tilt axis (upwardly in the middle position). become. Therefore, the furnace wall refractory surrounding the region where the secondary combustion occurs is worn out faster than that of other parts (furnace bottom, etc.), and is a matter that determines the repair interval of the converter. Of course, the operation must be stopped during repair (hereinafter referred to as furnace repair), but the period is currently 5 to 7 days, and shortening of this period is desired.
[0004]
By the way, one of the means for shortening this period is rationalization of furnace repair work.
For example, in the AOD (Argon Oxygen Decabrization) furnace used to receive molten steel from the converter and decarburize it in an argon atmosphere, the upper and lower parts of the furnace body can be separated, and the highly worn upper part can be replaced quickly. The furnace repair time is shortened. JP-A-4-235209 and JP-A-8-2334662 disclose that the furnace body is divided into two or three parts at the top and bottom and can be exchanged, and a necessary place is changed to a converter or an electric furnace. A steel furnace to be used is proposed.
[0005]
However, the AOD furnace is originally a simple converter in which a constricted cover portion called a cone is placed and connected to a cylindrical straight body through a flange, and is a conventional converter that mass-produces molten steel. As such, there is no large exhaust gas recovery device on the furnace. Therefore, the replacement | exchange operation | work of the said cone was able to be performed with the furnace body standing upright in the place which operates.
[0006]
Furthermore, the steelmaking furnaces described in JP-A-4-235209 and JP-A-8-2334662 are for mass production of molten steel. Therefore, if an attempt is made to separate and replace the furnace body, the on-furnace equipment becomes an obstacle, and it is necessary to carry out the furnace body in a state of 90 ° (rollover) or 180 ° (inverted). However, when working in such a state in a furnace that has been fully used and the bricks are worn out, there is a serious problem that the bricks of the furnace body cannot be supported and the bricks fall off. The furnace proposed in the publication is difficult to use.
[0007]
[Problems to be solved by the invention]
In view of such circumstances, an object of the present invention is to provide a split type converter in which a straight body brick does not fall off even if the upper part of the furnace body is separated from the lower part in a rollover or inverted state.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the inventors diligently researched the structure of the furnace body and the brick stack in which the brick is supported as it is even if the furnace body is divided and further overturned or inverted, and the results are obtained. Was completed as an invention.
That is, the present invention is a converter in which a cylindrical straight body part and a throttle part are sequentially connected to each other so as to be freely splittable on the furnace bottom part, and the division position of the straight body part and the throttle part is It is a furnace body division type converter characterized by being shifted to the throttle part side from the boundary between the linear motion part and the throttle part.
[0009]
Further, the present invention is a furnace body split type converter characterized in that positions divided into upper and lower parts of the throttle part are formed by flanges, and the flanges are fastened to each other by bolts, nuts or cotters. .
Furthermore, the present invention is a furnace body split type converter characterized in that a brick receiving metal is provided at a position where the brick portion is divided above and below the throttle portion.
[0010]
In addition, the present invention is also a furnace body split type converter characterized in that the furnace bottom portion is also separable.
In the present invention, the division position of the straight body part and the throttle part is shifted by a distance on the throttle part side from the boundary between the straight body part and the throttle part, so even if the furnace body rolls over or is inverted. The remaining bricks of the narrowed part support the bricks of the straight body part, and the dropping of the bricks is prevented. At that time, if a brick receiving piece is provided at each of the positions divided above and below the throttle portion, the drop-off preventing effect is further promoted.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described, including the background to the invention.
FIG. 4 shows a non-split type converter 1 used for producing a mother molten steel for producing stainless steel by melting and reducing chromium ore with a carbonaceous material. There, oxygen 16 is blown onto the surface of the molten metal 17 through an upper blown oxygen lance 2 provided above the furnace to perform smelting reduction of chromium ore, and CO gas generated from the molten metal 17 is generated in the upper space in the furnace. Secondary combustion occurs. Therefore, the atmospheric temperature of the upper space 3 reaches 1700 ° C., and the refractory 4 around it is accelerated by radiant heat.
[0012]
By the way, the furnace body of the converter 1 is formed so that the outer skin 18 is usually formed of a thick plate such as a steel plate for boiler, and the inside thereof is protected by sticking a refractory brick 4 or an irregular refractory. Further, the furnace body has a shape in which a furnace bottom portion 15, and a substantially cylindrical straight body portion 14 and a cone-shaped throttle portion 13 are sequentially connected thereto. In the conventional split type converter described in JP-A-8-233466 and JP-A-4-235209, for example, as shown by arrows A and B in FIG. The upper and lower parts are divided at the boundary of the body part 14 or at the straight body part 14. In this case, as described above, when the furnace body is turned over or inverted, the weight of the bricks and the refractory in the straight body portion 14 cannot be supported.
[0013]
In the present invention, as shown in FIG. 1, the division position is shifted from the boundary toward the narrowed portion 13 so as to avoid the structure of only the straight body portion. As a result, the shape of the throttle part and the bricks remaining in the straight body part 14 support the dead weight of the straight body part bricks even if the furnace body rolls over or inverts, so as to prevent them from falling off. became. In addition, since the distance from this boundary to a division | segmentation position changes with the magnitude | sizes of a furnace body, although it does not specifically limit in this invention, it is about 0.3-2m with the converter with a production capacity of 200 tons.
[0014]
Further, in this case, flanges 8 are respectively provided at positions divided above and below the throttle portion, and the flanges 8 are fastened to each other by bolts / nuts or cotters 9. This is because the division work can be easily performed. Further, according to the present invention, a brick receiving piece 19 is provided on each of the flanges 8 at the position divided above and below the throttle portion 13 to support the lining brick and the irregular refractory 4. This is because the support of bricks and the like is strengthened, and their falling off can be completely prevented.
[0015]
【Example】
Using the split converter (see FIG. 1) according to the present invention, the chrome ore smelting reduction operation was performed for 600 charges. Since the refractory 4 on the upper part of the furnace body was worn very much, the upper part of the furnace body was replaced.
The operation was performed in two ways: when the furnace body was rolled over (90 °) and inverted (180 °). First, when the roll is turned over, the worker removes the cotter 9 shown in FIG. 2 from the flange 8 while separating the cotter 9 shown in FIG. And the upper part of the furnace body in which the refractory was already constructed in another place was carried into the converter installation place with the crane 10 and attached to the lower part of the furnace body in the reverse order of removal. The working time during this period was 36 hours, and the furnace repair period was 2 days including the time required for cooling the furnace body.
[0016]
Next, as shown in FIG. 3, while the furnace body is supported by the lifter-equipped carriage 12 as shown in FIG. 3, the operator removes the cotter 9 from the flange 8 and removes only the separated upper part of the furnace body as described above. To do. And the upper part of the furnace body in which the refractory construction was applied from another place was carried into the converter installation place with the carriage 12 with the lifter and attached to the lower part of the furnace body in the reverse order of removal. The working time during this period was 24 hours, and the furnace repair period was 2 days including the time required for cooling the furnace body.
[0017]
In addition, since the modification from the conventional non-split converter to the split converter according to the present invention was simple, it could be carried out inexpensively without requiring a large facility cost. Further, in the above-described embodiment, the operation of separating the upper part by dividing the furnace body into two parts has been described. However, the present invention may be a three-divided converter that can also divide the furnace bottom part 15 from the straight body part 14 thereon. This is because the division of the bottom of the furnace does not require rollover or inversion, and has already been carried out using the carriage 12 with a lifter.
[0018]
【The invention's effect】
As described above, according to the present invention, the upper part of the furnace body can be easily replaced in a short time. As a result, the furnace repair period, which conventionally required 5 to 7 days, is shortened to 2 days, and it is possible to improve the productivity of molten steel and reduce the burden on the operator.
[Brief description of the drawings]
FIG. 1 is a longitudinal section showing an example of a divided converter according to the present invention.
FIG. 2 is a diagram showing an example of an operation of replacing the upper part of the furnace body by overturning the converter of FIG. 1;
FIG. 3 is a diagram showing an example of an operation for inverting the converter of FIG. 1 and exchanging the upper part of the furnace body.
FIG. 4 is a longitudinal sectional view showing an example of a conventional non-split converter.
[Explanation of symbols]
1 Converter (converter smelting reduction furnace)
2 Upper blown oxygen lance 3 Upper space 4 Refractory (brick, irregular refractory, etc.)
5 Furnace body 6 Tilt shaft 7 Hot water outlet 8 Flange 9 Cotter 10 Crane 11 Special jig 12 Carriage with lifter 13 Upper part of furnace body (throttle part)
14 Straight body part 15 Furnace bottom part 16 Oxygen 17 Molten steel (molten metal)
18 Skin 19 Brick receipt

Claims (4)

A converter in which a cylindrical straight body portion and a throttle portion are sequentially connected to each other in a freely splittable manner on the bottom of the furnace,
A furnace body split type converter characterized in that the dividing position of the straight body part and the throttle part is shifted to the throttle part side of the boundary between the linear motion part and the throttle part. The furnace body split type converter according to claim 1, wherein the upper and lower positions of the throttle part are formed by flanges, and the flanges are fastened to each other by bolts, nuts, or cotters. The furnace body split type converter according to claim 1 or 2, wherein a brick receiving piece is provided at each of the upper and lower positions of the throttle portion. The furnace body split type converter according to any one of claims 1 to 3, wherein the furnace bottom part is also separable.

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