JPS61197988A - Top-cover electrode-hole sealing device in arc heating type out-furnace smelting device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Field of Application) This invention is an intense light (arc) heated outside furnace smelter that heats molten steel in a ladle using electrodes, and is used to prevent re-oxidation of molten steel during treatment. This invention relates to a canopy electrode hole sealing device for preventing nitrogen from being picked up in steel.

(Conventional technology and its problems) Figure 4 shows an intense light (arc) heating type outside furnace scouring method in which the ?IF steel m in the outside furnace scouring chamber $11 is heated using a plurality of electrodes 2. This scouring device has an electrode hole 4a in a canopy 4 which is installed at the opening of an outside furnace scouring ladle 1 via a pot edge seal 3, and this canopy electrode. Hole 4
A frame is generated from the gap with the electrode 2 inserted into a,
This becomes an updraft and other parts of the equipment (mainly the pot rim seal 3)
This causes outside air to be sucked in from the contact gap (part),
This results in reoxidation of the ladle self-melting W4m,
There was a problem that a pickup phenomenon of nitrogen (N) in the steel occurred.

Therefore, conventionally, a sealing device having a structure as shown in FIGS. 5 and 6 has been provided to seal the gap between the electrode hole 4a of the canopy 4 and the electrode 2 to prevent upward flow of the frame.

This conventional canopy electrode hole sealing device has a lower base sealing body 5 made of refractory material and fixed to the electrode hole iron skin of the roof I4.
and an upper cap base body 6 formed of refractory material and installed so as to be horizontally slidable on the base seal body 5. The lower base seal body 5 has a hole with an inner diameter larger than the outer diameter of the electrode 2. 6, and a horizontal inert gas blowing hole 5a opened in the inner diameter hole (this blowing hole is arranged in the same direction as shown in FIG. (provided at an arbitrary angle) and
A vertical inert gas blowing hole 5b opened downward is provided, and the gap between the electrode hole and the electrode 2 is gas-sealed with the inert gas blown into the structure. Note that the vertically downward purge by the blow hole 5b serves to prevent splash from adhering to the electrode insertion portion and to prevent spark troubles caused by the electrode 2.

The cap seal body 6 is formed of a ring-shaped refractory material having an inner diameter hole (an electrode fitting hole into which the electrode 2 is slidably fitted so that the electrode 2 moves in the vertical direction by heating vibration) which is slightly larger than the outer diameter of the electrode 2. The base seal body is designed so that it can slide together with the electrode 2 against horizontal movement of the electrode 2 (horizontal movement due to imaging during heat treatment) while closing the inner diameter hole of the base seal body 5. It is installed on top of 5.

Therefore, the sealing device having the above-mentioned structure prevents the flame from rising from the gap between the canopy electrode hole 4a and the electrode 2 during heat treatment, the outside air being sucked in by the rising air, and the molten steel in the ladle being reoxidized by the sucked air. The above-mentioned seal body 5, which is made of a refractory material, has the feature of being able to prevent the above problem.
6 is worn out at a rapid rate due to the heat of electrode 2 and molten steel m (
The average wear rate is 0.44s* for base seal body 5
/ch, 0.22m/C for cap seal body 6
tl), so it became unusable after 300 previous uses.

In addition, as the number of times the seal body 5.6 is used increases, variations in the pick-up speed of nitrogen (N) in the steel begin to occur, and the average value gradually increases, so there is a problem in stability when used many times. . For this reason, it is actually 150 to 20
There was a problem in that the seal body 5.6 had to be replaced after about 0 uses.

[Means for solving problems]

In order to solve the above-mentioned conventional problems, the present invention provides a water-cooled structure in which the seal is provided with a water passage in the refractory,
It is characterized by suppressing heat-receiving wear and tear of the seal body and improving seal durability.

[Embodiments of the invention]

Hereinafter, embodiments of the present invention will be described with reference to the drawings in FIGS. 1 and 2. The sealing device for the canopy N pole hole in this arc-heated outside furnace scouring apparatus is covered with the opening of the outside furnace scouring ladle 1. A canopy 4 provided, an electrode 2 inserted into the ladle 1 through the canopy electrode hole 4a and heat-treating the molten steel m in the ladle,
Seal bodies 5 and 6 formed of refractories seal the gap between the electrode 2 and the electrode hole 4a (the lower base seal body 5 has inert gas injection holes 5a and 5 in the horizontal and vertical directions).
In the conventional device shown in FIGS. 4 to 6, the device has a structure in which the gap between the electrode hole 4a and the electrode 2 is sealed by the inert gas blown in from the blow hole. , the seal body 5.6 has a water-cooled structure with a water passageway 15.16 provided in the seal refractory, and the seal body 5.6
It is characterized by suppressing heat loss and improving seal durability.

In the case of this embodiment, the water passages 15 and 16 are formed of piping for passing cooling water embedded in the sealed refractory as shown in the figure.

(Effects of the Invention) Since the sealing device of the present invention employs the above-mentioned water-cooled structure for the refractory seal, the wear rate of the seal refractory is greatly reduced, and it can be used up to about 1000 times. , stable sealing performance was obtained even after multiple uses.Also, as is clear from the explanation in Figure 3, which compares the conventional method and the water cooling method of the present invention, the nitrogen CN of the molten steel in the ladle
The pick-up was also able to be stably maintained at a low level, and the pick-up speed was almost flat and did not change until about 1000 times, making it possible to heat treat the molten steel with as little re-oxidation as possible.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view showing the main parts of the device of this invention, Figure 2 is a cross sectional view taken along the line ■-■ in Figure 1, and Figure 3 shows the pickup speed of nitrogen in steel and the number of times the seal body is used. 4 is an explanatory diagram comparing the relationship between the water cooling method according to the present invention and the conventional method. FIG. 4 is an explanatory diagram showing the seal relationship showing the general structure of the conventional device.
The figure is a sectional view of the manufacturing part of the electrode hole sealing part of the conventional device.
The figure is a cross-sectional view taken along line VI-VI in FIG. 5. 1... Ladle for off-road scouring, m... Ladle self-melting steel, 2...
・Electrode, 4... Canopy, 4a... Canopy electrode hole, 5...
・Base seal body, 5a... Horizontal blowing hole for inert gas, 5b... Vertical blowing hole for inert gas, 6
...Cap seal body, Is, 16...Water passage.

Claims (1)

[Claims] A canopy installed over the opening of a ladle for outside furnace refining, an electrode inserted into the ladle through the canopy electrode hole and heat-treating molten steel in the ladle, and a connection between the electrode and the electrode hole. A refractory seal that is made of a refractory that seals the gap, has horizontal and vertical inert gas injection holes, and uses the inert gas blown through the injection holes to seal the gap between the electrode hole and the electrode. The seal is characterized in that the seal has a water-cooled structure with a water passage provided in the refractory, thereby suppressing heat-receiving wear and tear of the seal body and improving seal durability. Canopy electrode hole sealing device for arc heating type outside furnace scouring equipment.