JPH01122593A - Electrode for arc furnace - Google Patents

Abstract

PURPOSE:To reduce substantially the oxidized wear of a carbon electrode for an arc furnace and save the running cost of the arc furnace by coating the surface of the electrode with a conductive ceramic. CONSTITUTION:A conductive ceramic is coated on the surface of a carbon electrode for an arc furnace. The ceramic can thereby be used in a way similar to the case of an ordinary carbon electrode without any hindrance of electric current from an electrode holder, and the wear of the carbon electrode is substantially reduced. A boride having a high melting point, hardness and conductivity is used as the conductive ceramic. And, for example, the ceramic of a complex boride mainly composed of ZrB2 and TiB2 is mixed with a binder of liquid state and applied to the external surface of the rod-shaped carbon electrode, using a brush. Thereafter, the coat is naturally dried, thereby forming a film of 0.2mm to 0.5mm thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrode used in an arc furnace for steelmaking.

[Prior Art] Rod-shaped carbon electrodes used in arc furnaces for steelmaking gradually wear out from the tip due to oxidation caused by high heat, so as is well known, a new electrode is installed at the rear end of the worn-out electrode. Use by adding.

The cost associated with this consumption of electrodes has traditionally accounted for a large proportion of the total operating cost of an arc furnace, along with the electric power cost.

For this reason, SiO21AX has traditionally been used on the surface of carbon electrodes.
203 + T t 03 , MgO nanogold HI
Proposals have been made to prevent oxidative wear and tear by forming a coating layer of an oxidation-resistant material such as m-oxide or SiC. However, since these oxidation-resistant materials have no electrical conductivity, operations are carried out in the following manner. That is, in the operation of the arc furnace shown in FIG. 1, the electrode gripping part needs to be replaced as the electrode wears out, but this method does not apply a coating to the electrode gripping part.

Generally, the following two methods are adopted for this purpose.

One is the third one only on the part where the conductor is pressed as shown in Figure 2.
One method is to create a portion that is not coated in the vertical direction as shown in Figure 3A, and the other method is to determine the height of the electrode grip in advance and leave only this annular portion uncoated as shown in Figure 3B. However, both of these methods have the disadvantage that not all of the electrodes can be coated, and the amount of reduction in electrode consumption must be reduced accordingly.

Also, since the above coating method is only partial;
Coating requires great care; for example, the simple method of immersing the entire electrode in the coating solution cannot be used, and it requires a lot of man-hours.

There was a problem with the time required.

[Object of the Invention] Therefore, the present invention aims to suppress the consumption of carbon electrodes as much as possible without interfering with the power supply, and to reduce the running cost of an arc furnace.

[Means for Solving the Problems] In order to achieve the above object, the electrode for an arc furnace of the present invention is characterized in that the surface of a carbon electrode for an arc furnace is coated with conductive ceramics.

[Operation] The conductive ceramics can be used in the same way as ordinary carbon electrodes without interfering with the flow of electricity from the electrode holder, and the level of wear and tear is greatly reduced.

[Example] In this example, a boride is used as the conductive ceramic. Borides generally have high melting points and hardness;
It has the characteristic of being electrically conductive. The properties of the main borides are as shown in the robe.

In this way, borides have a melting point of 2000°C or higher, an electrical resistance of 50-80/jΩ'cm, and a Vickers hardness of 2000°C.
K g/cm” or more.And, Asahi Glass Co., Ltd. has given it the trademark name [ZrB21 as Ceramics J].
Composite boride ceramics containing T iB 21 as a main component are commercially available. These include those in which SiC is added to further improve oxidation resistance, or BN is added to improve thermal shock resistance.

The boride-based ceramic is then mixed with a liquid binder, coated on the outer circumferential surface of a rod-shaped carbon electrode with a brush, and air-dried to form a film with a thickness of 0.2 to 0.5+n+n.

Using the coated electrode in the operation of an arc furnace, the amount of electrode loss per 1 ton of melting was determined to be approximately 2.
A reduction of 0% was achieved.

In addition to the boride ceramics shown in this example, conductive ceramics include nitride ceramics such as TiN and ZrN, and other composite ceramics, but in order to further improve the oxidation loss, non-conductive ceramics such as SiC A conductive ceramic may be added to the conductive ceramic. In addition to this embodiment, coating may also be performed by spraying or dipping.

[Effects of the Invention] As explained above, according to the present invention, the conductive ceramics greatly reduce the oxidation wear and tear of the electrodes without inhibiting current flow from the electrode gripper, which is an extremely effective way to reduce the running cost of the arc furnace. has a beneficial effect.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an arc furnace, FIG. 2 is an enlarged plan view of its electrode holder, and FIGS. 3a and 3b are side views showing examples of conventional electrode coatings.

Claims (1)

[Claims] An electrode for an arc furnace, characterized in that the surface of a carbon electrode for an arc furnace is coated with conductive ceramics.