JP2515433B2 - Mounting structure of wall electrodes of DC arc furnace - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a furnace wall electrode of a DC arc furnace used for melting a metal material, refining a molten metal, etc., and more particularly to a mounting structure for a replacement part thereof.

[0002]

2. Description of the Related Art As an arc furnace for melting and refining, an electric current is passed between an electrode arranged above a molten metal charged in the furnace and an electrode attached to a furnace wall such as a furnace bottom or a side wall. A DC arc furnace for melting metal materials and refining molten metal is known. The furnace wall electrode in this type of DC arc furnace is exposed to an extremely harsh atmosphere due to heat received from the high-temperature molten metal in the furnace, Joule heat generated when a supply current passes through, and the like. Therefore, various proposals have been made to withstand this atmosphere and improve the durability of the furnace wall electrode, but in any case, the furnace wall electrode is worn out as the furnace operation progresses, and The electrodes have to be replaced.

In this furnace wall electrode replacement structure, an anode pin in which the furnace wall electrode portion is erected via a bottom plate and a refractory composition to be filled around the anode pin are integrally molded to form a cassette type furnace wall. When the electrodes are replaced, it is possible to easily repair and replace the electrode portion such as stamping, which was a poor work in the conventional furnace by replacing the electrodes for each furnace wall electrode. However, this has the following problems.

[0004]

Although the periphery of the anode (SS material) can be constructed in the factory, the periphery of the steel plate frame is stamped by so-called on-site construction, and therefore the furnace must be cooled, resulting in time loss. , Thermal loss, and loss due to cracks in the furnace material other than the repaired part due to cooling. Alternatively, in order to suppress these losses and wear, it is required to carry out the construction without cooling the furnace, but with this method, it is necessary to construct the refractory around the steel plate frame by working from inside the furnace. , Work in the high heat section. Since the stamps used on-site are in the working environment as described above, the quality of their construction is not sufficient, cracks and peeling of the stamp material occur, and the wear of the refractory around the furnace wall electrode becomes faster. However, the frequency of replacement will increase and the productivity of the electric furnace will decrease.

A conventional method is Japanese Patent Laid-Open No. 01-12839.
According to the publication No. 2, the furnace material filling layer collapses when the electrode block is removed downward, or when a new electrode block is attached, due to a manufacturing error between the electrode block and the furnace material filling layer, Inevitably gaps occur.
If the operation is carried out with this gap being generated, the molten steel will flow into this gap, and the molten steel will further flow out from the furnace bottom. Therefore, in order to prevent this gap from being generated, the furnace material filling layer around the electrode block needs to be installed on site by working from inside the furnace after the electrode block is attached.

The present invention is intended to solve the above-mentioned problems, and makes it possible to replace the furnace wall electrode only from the outside of the furnace, and it is not necessary to cool the furnace and the furnace wall electrode can be replaced in a short time. At the same time, it is an object of the present invention to provide a structure for attaching a furnace wall electrode of a DC arc furnace, which can release the replacement work environment from the high heat section.

[0007]

Means for Solving the Problems A furnace wall electrode mounting structure for a DC arc furnace according to the present invention for achieving the above object is provided with a fireproof structure around a conductive pin or billet erected via a furnace bottom plate. The wall of the DC arc furnace, which is filled with material and whose side wall is integrally formed into a taper shape, can be freely attached to the attachment hole of the electrode, which is opened in the hearth of the DC arc furnace. In the electrode mounting structure, a gap is provided between a side surface of the furnace wall electrode and a mounting hole of the furnace wall electrode, and a nozzle capable of press-fitting a refractory material from outside the furnace is provided in the gap.

As described above, the gap is provided between the side surface of the furnace wall electrode and the attachment hole of the furnace wall electrode, and the nozzle capable of press-fitting the refractory from the outside of the furnace is provided in the gap, whereby the furnace wall electrode After replacement, it is possible to press-in the refractory from the outside of the furnace,
All furnace wall electrode replacement work can be performed from outside the furnace.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of a furnace wall electrode mounting structure of the present invention.
FIG. 2 shows a detailed view of the attachment structure of the furnace wall electrode of the present invention.
As shown in FIG. 1, a furnace wall electrode 2 of a DC arc furnace has a furnace wall electrode 2 having a tapered side surface attached to a mounting hole 16 formed in a hearth 1, and the furnace wall electrode 2 has a conductive pin. Alternatively, a steel plate frame 9 for constructing the billet 3 and the refractory 4
Is attached to the furnace bottom plate 5. The furnace wall electrode 2 is attached to a mounting flange 7 protruding from a furnace metal member 6 of an electric furnace body via an insulator 8.

FIG. 2 shows the details of the mounting structure of this portion, in which the mounting flange 7 protruding from the furnace metal fitting 6 is
The furnace wall electrode 2 is fixed by a mounting bolt 11 from the outside of the furnace. Since the furnace body metal 6 and the furnace wall electrode 2 require electrical insulation, the inter-flange insulator 8, the flange inner surface insulator 10 and the mounting bolt insulator 1 are respectively provided at necessary portions.
Install 2.

In the state where the furnace wall electrode 2 is attached to the furnace body metal piece 6, between the removal surface 15 of the furnace floor 1 and the steel plate frame body 9,
A gap 14 is generated. Refractory is press-fitted into the gap 14 from nozzles 13 provided at several circumferential positions outside the furnace, and the gap 14 is filled. The amount of the gap is 10 to 50 mm
The degree is desirable. If it is less than 10 mm, the press-fitting material is not uniformly filled, and if it is too large, it is uneconomical, so the upper limit was made 50 mm. Further, within this range, a manufacturing error of the furnace wall electrode can be absorbed. Further, in order to more reliably fill the press-fitting material into the gap, at the time of repairing the mounting surface 15 when replacing the furnace wall electrode, the upper gap, that is, part a in FIG. 2 is repaired as much as possible. Should be done.

In this way, the furnace wall electrode 2 is attached from the outside of the furnace to the mounting hole 16 formed by the furnace body metal 6 of the electric furnace body and the hearth 1, and at the time of this mounting, the removal surface 15 of the hearth 1 By allowing the refractory material to be press-fitted from the outside of the furnace into the gap 14 generated between the steel plate frame body 9 and the furnace wall electrode 2, all the replacement work can be performed from the outside of the furnace. The steel plate frame 9 is a guide for filling the refractory when manufacturing the replacement furnace wall electrode, and may not be attached when replacing the furnace wall electrode in the electric furnace.

As described above, according to the present invention, it is possible to replace the furnace wall electrode only from the outside of the furnace, it is not necessary to cool the furnace, and the furnace wall electrode can be replaced in a short time. It was possible to release the working environment from the high heat section.
Moreover, as shown in Table 1, the replacement time of the furnace wall electrode was shortened to about 1/3 as compared with the conventional method.

[0014]

[Table 1]

[0015]

EFFECTS OF THE INVENTION By adopting the present invention, it is not necessary to cool the furnace when replacing the furnace wall electrode, so that cracks and the like of the furnace material other than the repaired parts are reduced, and stamping on site construction is omitted. Therefore, the wear of the refractory around the furnace wall electrode is reduced, and the life of the furnace wall electrode is extended, so that the replacement frequency is reduced and the productivity of the electric furnace is improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a furnace wall electrode mounting structure of the present invention.

FIG. 2 is a detailed view of the attachment structure of the furnace wall electrode of the present invention.

[Explanation of symbols]

 1 Hearth 2 Furnace wall electrode 3 Conductive pin or billet 4 Refractory 5 Furnace bottom plate 6 Furnace metallurgy 7 Mounting flange 8 Insulator between flanges 9 Steel plate frame 10 Flange inner surface insulation 11 Mounting bolt 12 Insulation for mounting bolt 13 Nozzle 14 Gap 15 Removal Surface 16 Furnace Wall Electrode Mounting Hole

Claims (1)

(57) [Claims] 1. A furnace wall electrode of a DC arc furnace in which a refractory material is filled around a conductive pin or billet which is erected via a furnace bottom plate and whose side surfaces are integrally formed in a tapered shape is used for a DC arc furnace. In a furnace wall electrode mounting structure of a DC arc furnace which can be freely mounted in a furnace wall electrode mounting hole opened in the hearth, a gap is provided between the side surface of the furnace wall electrode and the furnace wall electrode mounting hole. A structure for mounting a furnace wall electrode of a DC arc furnace, characterized in that a nozzle into which a refractory material can be pressed from outside the furnace is provided in the gap.