JPS63416A - Construction method for tapping hole of converter at changeable capacity operation - Google Patents

Abstract

PURPOSE:To secure the min. necessary taping time and to minimize the refining time by forming an optional tapping hole using forming jig for the prescribed tapping hole having different diameter and refining under changing molten steel quantity at each refining unit in the same converter. CONSTITUTION:Plural forming jigs 6 for tapping hole having taper part at one end and closed sack-like at the other end are prepared as matching molten steel capacity for easily changeable refining. Next, before starting the refining operation, the above jig 6 is selected as matching the molten steel capacity to change the size of tapping hole 3. In succession, monolithic refractory 14 is filled up into the gap 6 between the wall of the tapping hole 3 for converter 1 and the above jig to change the size of hole. And, the molten steel capacity is changed at each refining unit by the same converter 1 and refined.

Description

[Detailed description of the invention] (Industrial use) The present invention relates to a method for constructing a converter tapping hole.

(Prior art) A converter used for refining steel processes a certain amount of molten steel (t/ch).
), one refining is performed, and after completion of refining, the tapped steel is discharged into a container such as a ladle through a tapping hole provided on the side wall of the converter.

FIG. 5 is an overall view of the converter, with FIG. 5(a) showing a front cross section, and FIG. 5(b) showing a side view. Translation f l in body 1
8fi12 is discharged from the tapping hole 3 after blowing, but at the time of discharge, after raising the oxygen lance 4, as shown in FIG. Fifth
Referring to Figure (b), the upper part of the converter is tilted forward around the trunnion 5, and the molten steel 2 is discharged out of the furnace.

If this work is carried out, the inner refractory of the tap hole 3 will be worn out by the molten steel, causing deformation of the tap hole shape and local exposure of the steel shell, so it is necessary to repair the refractory as appropriate. In such cases, the conventional method was to restore the tap hole to a certain design depending on the size of the converter.

Repairs are made to the same diameter, length, etc. each time.

As a specific example of repair, JP-A No. 53-6,202,
There is a method shown in JP-A No. 55-138,014, and the method of JP-A No. 53-6,202 is to fill the entire tapping hole with repair fireproofing material and then drill the hole from the outside with a drill or the like. The method disclosed in JP-A-55-138,014 uses a sleeve brick with a steel pipe attached to the tapping hole, and fills the gap between the inner surface of the tapping hole and the sleeve brick with a repair material.

In all of the above cases, the diameter and shape of the tapping hole is repaired to restore it to a predetermined shape of the same size each time.

Originally, the diameter and shape of the tapping hole were determined according to the size of the converter, and at this time, the unit amount of molten steel (t/ch) during refining was determined.
The amount of steel was always almost the same for each refining process, and the shape of the tapping hole was also restored to the same shape each time it was repaired.

(Problems to be Solved by the Invention) However, the above working method causes the following problems. That is, when performing 1:7 refining by changing the amount of molten steel each time in a converter of the same capacity (hereinafter referred to as variable capacity refining), for example, when refining 250 tons/time of molten steel in a 250 mm converter, and 100 tons. /times of vI refining of molten steel, the time from start to end of tapping is significantly different if the diameter of the tapping hole is the same.

In particular, when refining a small volume of molten steel, the time required for tapping is short and the minimum required time may not be met. The minimum required tapping time is that when tapping steel from a converter to a ladle, etc., there is no alloy or deoxidized material in the ladle. ) and other additives may be added and stirred and mixed according to the tapping flow, which requires a certain amount of tapping time or more. Furthermore, if the tapping hole diameter is always set small in accordance with small-volume blowing, the tapping time from the start to the end of tapping during large-volume molten steel blowing will be prolonged, leading to a decrease in work efficiency.

(Means for Solving the Problems) The present invention has been made to solve the above-mentioned problems. In variable capacity refining in which refining is performed by changing the amount of lli, the size of the furnace outlet hole is constructed to match the amount of molten steel for each refining before the start of refining. In other words, in order to secure the minimum required tapping time and to minimize the time from the start to the end of tapping, when the amount of refining and molten steel is large, the tapping hole is set as a dog, and when the amount of refining molten steel is small, the tapping hole is set as a dog. Make the steel hole smaller.

Specific examples of the present invention will be explained in detail below using the figures.

Several types of tapping hole forming jigs 6 shown in FIG. 2 are prepared depending on the amount of molten steel to be used for variable capacity refining. The tapping hole forming jig 6 has a tapered portion 7 at one end and a closed bag shape at the other end. Further, one or more phase outlet ports 8 may be provided at appropriate positions in the length direction or in the circumferential direction. Then, a jig fixing object 9 such as a power wall is wrapped around the boundary between the tapered part 7 and the straight pipe part.

The maximum outer diameter of the tapered part is larger than the tap hole diameter of the converter, and the length is larger than the tap hole length. Also, for spraying, use the phase outlet 8.
The length Q from to the boundary between the tapered part and the straight pipe part is set according to the variable capacity, and the necessary number of types are prepared.

Fig. 3 is a diagram when the tapping hole forming jig 6 is installed in the tapping hole 3, and the converter main body 1 is tilted to make the tapping hole 3 almost horizontal, and then the amount of molten steel for next refining can be prepared. Then, a jig 6 of an appropriate diameter is inserted using a forklift 10 or the like so that the re-tapered portion is positioned outside the furnace. At this time, a jig fixture 9 is filled between the jig 6 and the inner wall of the tapping hole 3, and the jig 6 is fixed to the tapping hole 3.

FIG. 4 is an explanatory diagram of the material spraying work for spraying refractories. After inserting the tapping hole forming jig 6 explained in FIG. 3, the converter main body 1 is further tilted and The jig 6 is tilted until its longitudinal direction becomes almost vertical, and then stopped. Thereafter, the refractory spraying device 11 sprays the monolithic refractory 14 into the gap between the J: hole-extinguishing jig 6 and the tapping hole 3. In Figure 4, 1
2, the heat shield plate 13 is a spray material tank.

Fig. 1 is a diagram when the spraying of the monolithic refractory material is completed, and the spraying material 14 fills the gap between the tapping hole 3 and the jig 6, and the upper part of the spraying material reaches the phase outlet 8. The material 14 overflows from the outlet 8 into the jig 6 and falls out of the furnace from the open lower part, and when it is confirmed that the target length Q has been reached, the work is completed.

Leave the jig 6 inserted, and when discharging the molten steel after refining, l
Melt with molten steel.

Incidentally, the phase outlet 8 is not necessarily required for spraying, and spraying is not necessary when the length Q is the same as the length a□ of the tapping hole 3. In this way, a tapping hole with the desired diameter and length is constructed, and the diameter and length are determined in advance according to the amount of molten steel to be refined, and tapping hole forming jigs are prepared for each. put.

The meaning of setting the length Q for spraying monolithic refractories is that spraying will wear out almost all of the material 14 in one tapping operation, which will hinder the construction of a tapping hole with a different diameter and length the next time. This is because there is no Especially when performing large-capacity smelting after small-volume smelting,
Since it is necessary to increase the diameter of the tapping hole from small to large, it is effective to set the length for the above-mentioned blasting.

As an example of the specific size of the tapping hole forming jig 6, 2
When refining molten steel of 70 to 270 in a converter, L is 2000 mm.
, d is 250 mm, and the material temperature outlet 8 is not provided for spraying. When refining 170 in a similar converter, Q is 1000.
mm.

d is 200mm, and when refining tiot, Q is 800mm,
Use one with d of 170 mm.

(Effect of the invention) By implementing the present invention, i8
When carrying out work with a large amount of steel, it is possible to secure the necessary minimum tapping time and minimize the tapping time to increase work efficiency, and also shorten the time required to construct the tapping hole. It can be time.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the present invention when spraying of monolithic refractories is completed;
Figure 2 is a diagram of the tapping hole forming jig used in the present invention, and Figure 3 is a diagram of the tapping hole forming jig used in the present invention.
The figure is a diagram when the tapping hole forming jig is inserted into the tapping hole, No. 4
The figure shows the process of spraying monolithic refractories, and FIG. 5 shows the overall structure of the converter. Converter body 2: Molten steel 3: Tapping hole 4: Oxygen lance 5: Trunnion 6: Tapping hole forming jig 7: Taper part 8
: Material temperature outlet for spraying 9: Jig fixed object 10: Forklift 11: Equipment for spraying refractories 14: Material for spraying Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) A variable capacity operation characterized by changing the size of the converter tapping hole in accordance with the amount of molten steel before the start of refining when refining is performed using the same converter, changing the amount of molten steel for each refining unit. How to construct a tap hole in a converter. (2) A patent for changing the size of a tap hole in a converter by using a pipe-shaped tapping hole forming jig with a tapered opening at one end and a closed end at the other end, and selecting the diameter appropriately according to the amount of molten steel to be refined. A method for constructing a tap hole in a converter during variable capacity operation according to claim 1.