JPH0639638B2 - Power supply device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a power feeding device in a melting furnace such as an electroslag remelting furnace or a vacuum arc furnace in which a rod-shaped electrode is suspended in a conductive crucible. .

[Prior Art] An electroslag remelting furnace is disclosed in, for example, Japanese Patent Publication No. 51-28.
As described and known in Japanese Patent No. 043, a rod-shaped consumable electrode, which is a melting material vertically held by a gripper, is hung in a conductive crucible made of copper having a water cooling structure, and one end of a power source is The current is passed through the slag layer in the crucible while the other end of the electrode is connected to the crucible and the resistance is heated to melt the tip of the electrode. Also, as is well known, the vacuum arc furnace is a furnace in which the crucible is kept in a vacuum and an arc is generated between the lower end of the consumable electrode and the molten metal surface to melt the consumable electrode by arc heating.

However, in any of the above melting furnaces, a large amount of electric power is supplied to the electrodes via the conductive cable, so a strong unequal magnetic field is generated near the melting surface, which may cause the molten metal to be agitated unnecessarily and segregate. I got it. In order to solve such a problem, a substantially cylindrical conductive cover body is fixed so as to cover the upper opening of the crucible, and the other end of the power source is connected to the cover body so as to be concentric with the electrode. It has been attempted to weaken the influence of the magnetic field and reduce the reactance by eliminating the magnetic field by the effect of canceling the magnetic field by the coaxial axial feeding so that the current flows and the segregation is eliminated.

However, the cover body is not always pressure-bonded uniformly to the upper end opening edge of the crucible in the circumferential direction, and the electric power feeding system path from the cover body to the crucible is deviated on the circumference due to the difference in electric contact resistance. As a result, the problem does not occur in the core axial power supply, and the above problems have not yet been solved.

[Means for Solving Problems] The present invention is intended to solve the above problems, and therefore, the power supply device for a melting furnace according to the present invention has an electroslag re-arrangement in which electrodes are suspended in a conductive crucible. In a melting furnace such as a melting furnace or a vacuum arc furnace, a substantially cylindrical conductive cover body covering the upper opening of the conductive crucible is provided, and the lower edge portion of the conductive cover body is circumferentially multi-divided. A large number of electrically conductive brushes are provided, and each of the electrically conductive brushes is evenly pressed against the upper opening edge of the electrically conductive crucible by an elastic body to supply electric power from the electrically conductive cover body to the electrically conductive crucible. It is characterized by doing so.

[Operation] Electric power is evenly supplied from the conductive cover body to the conductive crucible on the circumference, and core axial power feeding can be reliably performed.

[Example] Fig. 1 shows an outline of the entire melting furnace. In the figure, 1 is a conductive crucible, and an outer wall 2 is formed around the crucible so that cooling water flows inside. 3 is an electrode suspended in the crucible 1; 4 is a stingarod supporting the electrode;
Reference numeral 5 is a molten metal, and 6 is a steel ingot formed in the crucible 1. Reference numeral 7 denotes a cylindrical conductive cover body covering the upper end opening of the crucible 1. The cover body also has a double-walled peripheral wall so that cooling water can flow into the hollow portion 8. A power supply 9 is connected between the upper end of the stinging rod 4 and the upper end of the cover body 7. The stingard rod 4 and the cover body 7 are electrically insulated by an insulator 11. Then, on the lower edge portion of the conductive cover body 7, as shown in an enlarged view in FIGS. 2 to 4, a large number of conductive brushes which are multi-divided in the circumferential direction.
Provide 12, 12, ... That is, the annular body 15 is fixed to the flange portion 13 forming the lower end portion of the cover body 7 with bolts 14, 14, ... And the outer circumference of the annular body 15 is fixed to the lower surface of the flange portion 13 in the circumferential direction at regular intervals. A large number of guide shafts 16, 16 are suspended, and block-shaped conductive brushes 12, 12 ... are loosely fitted on the guide shafts 16, 16 ... to attach the conductive brushes so that they can slide up and down. The guide shafts 16, 16 are provided with elastic bodies 18, 18 on the outer circumference of which a plurality of disc springs are laminated, and the conductive brushes 12, 12 are pressed downward by the elastic bodies. The step portion 19 formed on the outer peripheral surface of the annular body 15 is adapted to engage with the step portion formed on the inner peripheral surface of the conductive brushes 12, 12 ,. It works as a stopper so that it does not fall down. 20, 20 ... are several thin copper plates stacked so as not to impair flexibility
It is fastened to the upper surface of 13 with a screw 21 and the other end of each conductive brush 12, 12, ...
Is a flexible power feeding conductor fixed to the outer surface of the with screws 22. In this way, the conductive brushes 12, 12, ... Are pressed against the upper edge 23 of the conductive crucible 1. With this structure, the lower edge of the cover body 7 and the upper edge of the crucible 1 are electrically connected to each other with substantially equal contact resistance in the circumferential direction, so that the power feeding conductors 20, 20 ,. , The required electric power is evenly supplied to the upper opening edge 23 of the crucible 1 via the conductive brushes 12, 12 ...

[Effects of the Invention] As described in the above embodiments, according to the power feeding device of the present invention, the bias of the power feeding path from the conductive cover body to the conductive crucible on the circumference is prevented, and the core axial power feeding is possible. Since it is smoothed, it is advantageous that the reactance is increased and the segregation in the steel ingot due to the non-uniform magnetic field can be surely prevented and the quality is improved.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a vertical sectional view of a melting furnace, FIG. 2 is an enlarged view of a main part thereof, and FIG.
FIG. 4 is a vertical sectional view taken along the line AA of FIG. 4, and FIG. 4 is a sectional view taken along the line BB of FIG. 1 ... Conductive crucible, 3 ... Electrode, 7 ... Conductive cover body, 9 ... Power supply, 12 ... Conductive brush, 16 ... Guide shaft, 18
...... Elastic body, 20 ...... Power supply conductor.

Claims (1)

[Claims] 1. In a melting furnace such as an electroslag remelting furnace or a vacuum arc furnace in which an electrode is suspended in a conductive crucible, a substantially cylindrical conductive cover body covering an upper end opening of the conductive crucible is provided. A plurality of conductive brushes that are multi-divided in the circumferential direction are provided at the lower edge of the conductive cover body, and the conductive brushes are evenly pressed against the upper opening edge of the conductive crucible by an elastic body. A power supply device for a melting furnace, wherein electric power is supplied from the conductive cover body to a conductive crucible through a conductive brush.