JP2624504B2 - Converter structure with no falling furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a converter structure, and more particularly to a non-metallic furnace suitable for mainly decarburizing and dephosphorizing mainly hot metal subjected to hot metal pretreatment. The present invention relates to a falling steel tapping type converter structure.

<Conventional Technology> FIG. 5 shows a conventional converter structure. The normal operation method using the converter structure shown in FIG. 5 will be described. First, the converter 1 is tilted by about 60 ° to the charging side, and the hot metal put in the hot metal pot (not shown) is charged into the converter 1. I do. After the hot metal is charged, the upper blowing lance 12 is lowered into the furnace while the converter 1 is vertical, and oxygen is blown to the molten steel 3 and the slag 4 stored in the furnace bottom 6 to start decarburization blowing. At the same time, a dephosphorization treatment is also carried out by feeding auxiliary materials from above the furnace during blowing.

After the blowing, the converter 1 is moved to the trunnion shaft 13 until the straight line A shown in FIG.
When the steel is first tilted by about 75 ° to the tapping side, the molten steel 3
The slag 4 moves to the tapping side of the furnace wall 2 and taps the molten steel 3 from the tapping port 5. Just before tapping is completed, the tilt angle of the converter 1 increases and tilts to about 100 °. Then, when the slag 4 starts to come out of the tapping hole 5, the converter 1 is returned vertically and the slag is cut.

In order to measure the molten steel component in the converter 1 before tapping,
The converter 1 is moved to the charging side by about 80 until the straight line B shown in the figure becomes vertical.
サ ン プ リ ン グ Sampling of molten steel 3 is performed by tilting. <The problem to be solved by the invention> However, the above-mentioned conventional converter structure has the following problems.

(1) The bricks of the furnace wall 2 (for example, bricks made of magnesia carbon) are oxidized and worn by oxygen blown from the upper blowing lance 12 during blowing in the converter 1.

(2) The furnace wall brick in the slag line portion where the slag 4 comes in contact with the sampling work before the furnace or during tapping is oxidized and worn.

(3) When the converter 1 is tilted to the tapping side for tapping, the slag 4 comes out from the tapping port 5 first, and slag is mixed into a pot (a molten steel pot) that receives molten steel, and rephosphorization and resulfurization are performed. (P and S in the slag return to the molten steel again) occurs, and the amount of inclusions increases, so that the processing time in the secondary refining becomes longer, and finally, the quality of the slab and the steel material is reduced.

(4) tapping position level molten steel 3 due to the high long time in contact with the outside air, the molten steel temperature drop,吸窒(the N ₂ in the air from entering the molten steel), more brick life of受鋼pot Is reduced.

Conventionally, there has been proposed a method of tapping the bottom of a furnace, and in a converter, Japanese Patent Application Laid-Open No. 58-81910 discloses a method of tapping by providing a sliding nozzle at the bottom of the furnace. However, since the sliding nozzle is provided at the furnace bottom just below the fire point of the upper blowing lance, maintenance is extremely difficult, and there is a fatal drawback that a steel leak accident during blowing is more likely to occur.

On the other hand, furnace bottom tapping has also been attempted in electric furnaces, for example, JP-A-59-86887 and JP-A-61-149779, in which a protrusion is provided at the bottom of an electric furnace, and the protrusion can be opened and closed. Means for providing a tapping hole is disclosed.

Means for providing a tapping port that can be opened and closed at the protruding portion is more advantageous in eliminating the steel leakage problem than means for providing a sliding nozzle immediately below the firing point of the converter, and the present invention has been improved with this as a hint. It is another object of the present invention to solve the above-mentioned conventional problems and to provide a converter structure capable of extending the life of a furnace body.

<Means for Solving the Problems> The present invention for achieving the above object will be described with reference to Figs. 1 to 4 corresponding to the embodiment. A molten steel tapping portion 6a is provided by projecting the furnace bottom molten steel storage portion 6 of the converter furnace body 1 outward, a tapping outlet 9 that can be opened and closed is provided at the bottom of the molten steel tapping portion 6a, and a tapping port seal is provided at the top. Of the converter furnace body 1 above the furnace bottom molten steel reservoir 6 lined with a refractory and having a charging side area that may come in contact with the hot metal and steel charged therein. It is characterized by lining with a refractory 7 and lining with water-cooled panels 8 in other areas mainly on the tapping side.

The reason why the molten steel tapping portion 6a is projected is to facilitate the maintenance of the tapping port 9 and to facilitate the work of putting sand for sealing into the tapping port 9; A mouth 11 is provided.

The tap hole 9 is located at a position level at which the molten steel 3 and the slag 4 can all be discharged in a state where the converter body 1 is tilted by about 45 ° without falling down as in the conventional case. For tapping, for example, a flapper type opening / closing device 10 is provided. Sand is injected into the steel outlet 9 from the side of the converter body 1 with the opening and closing device 10 closed from the sand inlet 11 to perform sand sealing.

The height of the molten steel tapping section 6a is, for example, at least 10
It is set to 00 mm, and the upper end level is made coincident with the furnace bottom molten steel storage section 6. Then, in the converter furnace body 1 separated from the tapping port 9 by 1000 mm or more, the charging side area where there is a possibility of contact with the charged hot metal and steel, that is, until the straight line C shown in FIG. When the converter furnace body 1 is tilted by about 60 ° and the hot metal is received from the hot metal pot, the lining area of the refractory 7 is determined in consideration of the area that comes into contact with the hot metal or the area that comes into contact with the molten steel during sampling before the furnace.

For example, as shown in FIG. 2, the area in which the refractory 7 is lined is wider than the area in contact with the hot metal with a margin of 200 mm or more, and the upper end of the furnace bottom molten steel storage section 6 extends from the upper end of the converter furnace body 1. And the lower end covers half of the converter furnace body 1 at the lower end.

The other part of the converter furnace body 1 in which the refractory 7 is lined, that is, the tapping side is mainly used.
A region that is not in contact with the hot metal that is far away is lined with a water cooling panel 8. The water-cooled panel 8 has a zigzag water passage 8a as shown in FIG. 3 (enlarged view of a part in FIG. 2), and many such water-cooled panels 8 are arranged and lined.

In FIG. 1, a top-blowing converter having no tuyere in the furnace bottom molten steel storage section 6 has been described. However, the present invention can be applied to a converter having a bottom-blowing tuyere. It can also be used for bottom blown converters.

If the hot metal that has been subjected to the hot metal pretreatment is blown only by decarbonization and dephosphorization in the converter, sampling before the furnace after the completion of the converter blowing is no longer necessary, and the converter immediately after blowing is completed. The furnace body 1 can be tilted to the tapping side by about 40 °, the opening and closing device 10 can be opened, and tapping work can be performed from the tapping port 9.

Embodiment An embodiment of the present invention will be described below with reference to FIGS.

First, before the hot metal is charged into the furnace, the opening and closing device 10 for the tap hole 9 is prepared.
Is closed, and sand is injected from the sand inlet 11 to sand seal the tapping outlet 9. Then, the hot metal 3 is charged while the converter furnace body 1 is tilted by about 60 °. Since the furnace wall on the charging side is lined with brick 7, there is no hindrance to charging hot metal.

After the hot metal is charged, the converter furnace body 1 is returned to the vertical state, and oxygen gas is blown from the upper blowing lance 12 to perform blowing. At this time, there is a possibility that the hot metal (or molten steel) 3 will fly off and directly contact the water-cooled panel structure 8 to cause troubles such as erosion. To prevent this, slag is previously attached to the surface of the water-cooled panel structure. It is preferable to apply a coating by such means.

As the slag coating means, coating is performed by a suitable means such as spraying nitrogen gas to the molten slag remaining in the furnace and scattering it, or immersing a rotary impeller in the molten slag and scattering it.

In addition, the refractory structure 7 on the charging side is directly coated with slag prepared by adding light-burning dolomite to the slag generated in the previous blowing to prevent oxidation during blowing, and tilting the converter furnace body 1 with the slag adjusted. can do.

After the blowing, the opening and closing device 10 of the tap hole 9 is opened to discharge the molten steel 3. In order to shorten the tapping time, in order to increase the molten steel depth, the converter may be tilted to the tapping side. First
As shown in the figure, even if the gradient of the bottom brick of the furnace bottom molten steel storage section 6 is 10 ° at the time of the new furnace, it becomes close to 30 ° at the end of use. About ゜ is required. Then, when slag starts to be discharged from the tapping hole 9, the converter furnace body 1 is set in a vertical state, slag cutting is performed, and the tapping is completed.

<Effects of the Invention> By employing the converter of the present invention, the following effects can be obtained.

(1) By making the furnace wall brick part a water-cooled panel, the basic unit of brick can be improved.

(2) The slag cut rate is improved, the amount of molten steel components and inclusions are reduced, and the quality of slab steel is improved.

(3) Since the tapping is performed from the bottom, the tapping position is lowered, so that the temperature of the molten steel decreases, the nitrogen absorption, and the life of the steel receiving pot brick can be improved.

[Brief description of the drawings]

1 is a sectional view showing an embodiment of a converter structure according to the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG.
FIG. 4 is an enlarged partial cross-sectional view showing an a portion of FIG.
FIG. 5 is a cross-sectional view taken along line BB of FIG. 5, and FIG. 5 is a cross-sectional view showing a converter structure according to a conventional example. 1 ... converter furnace body, 2 ... furnace wall, 3 ... molten steel, 4 ... slag, 5 ... tapping outlet (conventional), 6 ... furnace bottom molten steel storage section, 7 ... refractory (side wall) ), 8: water-cooled panel, 9: tapping outlet (invention), 10: switchgear, 11: sand inlet, 12: top blow lance, 13: trunnion shaft.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hideo Takeshi 1-chome, Mizushima-Kawasaki-dori, Kurashiki-shi, Okayama Pref. Kawasaki Steel Corporation Mizushima Works (56) References JP-A-62-235413 (JP, A ) Japanese Utility Model 1-136395 (JP, U) Japanese Utility Model sho 64-22761 (JP, U)

Claims (1)

(57) [Claims] 1. A molten steel tapping section is provided by projecting a furnace bottom molten steel storage section of a converter furnace body outward, a tapping opening is provided at the bottom of the molten steel tapping section, and a tapping port seal is provided at an upper portion. In the converter furnace body above the furnace bottom molten steel storage part provided with a sand inlet for refractory and lined with refractory, the charging side area where there is a possibility of contact with the charged hot metal steel is refractory. A converter structure of a non-falling furnace tapping type, characterized by lining a water-cooled panel in other areas mainly on the tapping side.