JPH01183090A - Prevention method for oxidation of arc furnace electrode - Google Patents

Abstract

PURPOSE:To enable cooling of electrodes without removing them from a furnace by providing a furnace lid swing device on the arc furnace and by lifting the electrodes, swinging them together with the furnace lid, and lowering the electrodes at a specific position to allow the electrodes to touch cooling water. CONSTITUTION:Electrodes 4 of an arc furnace 1 are raised by an electrode elevation device 7, electrodes 4 are lifted together with a furnace lid 3 by a furnace lid swing device 11 and are swung. The furnace lid 3 and the electrodes 4 are moved to directly above the cooling device 12. A tank storing cooling water is provided inside the cooling device 12, and when the electrodes 4 are lowered at said position by the elevation device 7, the electrodes 4 are immersed in cooling water. By this processing, the red heated surfaces of electrodes 4 are definitely and quickly cooled and the temperature is reduced. As explained above, since the portions of electrodes 4 inside the furnace are brought in direct contact with the cooling water without the electrodes being taken out of the furnace, the electrode surfaces can be protected from oxidation. Furthermore, as this device does not require hands to move the electrodes, the work becomes easier.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) This invention relates to a method for preventing surface oxidation of graphite electrodes in an arc furnace.

[Conventional technology]

In arc furnaces for steelmaking, graphite electrodes are used as electrodes, but the electrodes themselves rise in temperature due to arc heating and become red hot, resulting in oxidation of the surface and progressing wear and tear, which is uneconomical. In order to reduce this surface oxidation of the electrode, Japanese Utility Model Publication No. 59/23357 proposes a cooling device in which the surface of the electrode protruding upward from the furnace lid is spray-cooled using a spray nozzle.

[Problem that the invention seeks to solve]

However, in the above-mentioned cooling device, since the electrode inside the furnace is indirectly cooled by cooling the outside of the furnace, the temperature decrease at the lower end of the electrode is small, and the effect of preventing surface oxidation is small. The above publication also discloses a device that forcibly cools the electrode taken out of the furnace by spraying cooling water when adding a furnace external fitting or repairing the furnace. However, with this device, it is necessary to remove the electrode from the furnace. It cannot be used while the furnace is in operation, and even when the furnace is not operating, the electrodes must be removed from the furnace for cooling only, transported to the cooling device, kept in the cooling device, and then installed in the furnace after cooling, which is extremely complicated. Requires work.

The present invention solves the above-mentioned conventional problems and provides a method for preventing oxidation of an electrode in an arc furnace, which can reliably and easily cool the inner part of the electrode in the furnace and prevent surface oxidation without removing the electrode from the furnace. That is.

[Means for solving problems]

However, in the method of the present invention, in an arc furnace equipped with an electrode lifting device and a furnace lid rotating device, the electrode whose temperature has been raised is rotated to the side of the furnace shell together with the furnace lid by the furnace lid rotating device, and then the electrode is lifted and lowered. This is a method for preventing oxidation of an electrode in an arc furnace, which is characterized by lowering the electrode using a device and bringing cooling water into contact with the electrode directly below the rotation path of the furnace lid to lower the electrode surface temperature.

In this invention, the contact between the cooling water and the electrode may be carried out by immersing the electrode in the cooling water, or by spraying the cooling water toward the electrode from a water spout.

[Effect]

In the cooling method of the present invention, the electrode raised by the electrode lifting device is rotated together with the furnace lid by the furnace lid turning device of the arc furnace, and the electrode is lowered by the electrode lifting device. ) reaches just below the furnace lid rotation path. By bringing the electrode into contact with the cooling water stored in the tank or the cooling water injected from the water spout at this position, the electrode surface is directly, quickly and reliably cooled, the temperature decreases, and wear due to surface oxidation is suppressed. Ru.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG.

In the figure, 1 is an arc furnace, 2 is its furnace shell, and 3 is a furnace lid. Reference numeral 4 denotes an electrode made of graphite, which is held at the tip of an electrode support arm 5 via a gripper, and an electrode support 6 that supports the base end of each electrode support arm 5 is driven up and down by an electrode lifting device 7. It has become. Reference numeral 8 denotes a furnace lid suspension beam connected to the furnace lid 3 via a hanging rod 9, the base of which is fixed onto the machine frame of the electrode lifting device 7.

Reference numeral 10 denotes a tilting floor that tilts together with the furnace shell 2, and 11 a furnace lid rotating device installed upright on the tilting bed 10, which rotates and slightly raises and lowers the furnace lid 3 and electrodes 4 via the electrode lifting device 7. be. Further, reference numeral 12 denotes a cooling device, which is provided at a position directly below the turning path of the furnace lid 3 by the furnace lid rotation device 11.
Cooling water 15 is stored in a tank 14 fixedly installed above.

In the apparatus configured as described above, when charging scrap during furnace operation or at the end of operation, the electrode 4 is raised by the electrode lifting device 7, the furnace lid rotating device 11. The furnace lid 3 and the electrodes 4 are lifted and rotated to move the furnace lid 3 and the electrodes 4 directly above the cooling device 12 as shown by the chain line in FIG. Next, as shown by the solid line in FIG. 2, the electrode 4 is lowered by the electrode lifting device 7 and immersed in the cooling water 15 in the tank 14. As a result, the red-hot surface of the electrode 4° is reliably and rapidly cooled, and its temperature is lowered. After cooling, the electrode 4 may be raised by the electrode lifting device 7 and placed on standby in preparation for the next insertion into the furnace.

3 and 4 show other embodiments of the invention, in which the same parts as in FIG. 1 are given the same reference numerals. In this embodiment, a cooling device 21 is used that can freely traverse on rails 20 laid on a foundation 13. This cooling device 21 has a tank 23 loaded on a self-propelled trolley 22 placed on a rail 20, and multiple stages of annular piping 24 are provided along the inner wall surface of the tank 23. A large number of water spouts 25 opening toward the center of the tank are provided, and each pipe 24 is connected to a water supply pipe 26 extending vertically. This water supply pipe 26 is connected to a cooling water supply source 28 such as a water supply via a detachable hose 27. 29 is a drain cock.

In the apparatus configured as described above, the tank 23 is stopped directly below the rotation path of the furnace cover 3, and cooling water is supplied from the water spout 25 to the electrode 4 inserted into the tank 23 in the same manner as in the previous embodiment. The liquid is sprayed to cool the electrode surface.

In this embodiment, the cooling device 21 is convenient because unused parts can be evacuated to a position where they will not get in the way, and one cooling device 21 can be shared by multiple arc furnaces. .

FIGS. 5 and 6 show still another embodiment of the present invention, in which the same parts as in FIGS. 1 to 4 are given the same reference numerals as in these drawings. In this embodiment, a spirally wound pipe 31 is fixed to a pillar 30 which is erected and fixed on a foundation 3, and this pipe 31 has a large number of water spouts opening toward the center of the spiral. A cooling device 32 having holes 25 is used. This cooling device 32 is provided at a position directly below the turning path of the furnace lid turning device 11 of the furnace lid 3. The receiver 33 is a dish-shaped drainage receiver, but instead of this, drainage may be drained directly into a pit provided in the foundation 3. Further, 28 is a cooling water supply source connected to the pipe 31.

That is, this embodiment is similar to the tank 2 of the embodiment shown in FIG.
1 and the trolley 22 are omitted, and the electrode 4 is cooled by cooling water injected from the water spout 25 as in the previous embodiment.

The present invention is not limited to the above embodiments; for example, the tank 14.23 is
The piping 31 may be mounted on the trolley 22 so as to be able to rise and fall freely. Further, the present invention can also be applied to an arc furnace in which the furnace cover rotating device 11 is installed upright on the foundation 13.

〔Effect of the invention〕

As explained above, according to the present invention, without removing the electrode from the furnace, the inner part of the electrode can be brought into direct contact with cooling water to reliably cool it and prevent surface oxidation. Further, the movement of the electrode for cooling can be easily performed using an electrode lifting device and a furnace cover rotating device of the arc furnace.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an example of the apparatus used in the method of the present invention, FIG. 2 is a partially cutaway front view, and FIG. Figure equivalent diagram,
4 is a sectional view taken along the line A-A in FIG. 3, FIG. 5 is a view corresponding to FIG. 2 showing still another example of the apparatus used in the method of the present invention, and FIG. It is a sectional view taken along the B line. 1... Arc furnace, 2... Furnace shell, 3... Furnace lid, 4...
... Electrode, 7... Electrode lifting device, 11... Furnace lid rotation device, 12... Cooling device, 14... Tank, 15...
...Cooling water, 20...Rail, 21...Cooling device,
22... Trolley, 23... Tank, 24... Piping,
25... Water spout, 26... Water supply pipe, 28... Cooling water supply source, 30... Support column, 31... Piping, 32...
··Cooling system.

Claims (1)

[Scope of Claims] 1. In an arc furnace equipped with an electrode lifting device and a furnace lid rotating device, the electrode whose temperature has risen is rotated to the side of the furnace shell together with the furnace lid by the furnace lid rotating device, and then the electrode lifting device 1. A method for preventing oxidation of an electrode in an arc furnace, which comprises lowering the electrode to bring cooling water into contact with the electrode directly below the rotation path of the furnace lid to lower the electrode surface temperature. 2. The method for preventing oxidation of an electrode in an arc furnace according to claim 1, wherein the electrode is brought into contact with the cooling water by immersing the electrode in cooling water stored in a tank. 3. The method for preventing oxidation of an electrode in an arc furnace according to claim 1, wherein cooling water injected from a water spout is brought into contact with the electrode.