JPH0639634B2 - Electroslag remelting furnace and its operating method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electroslag remelting furnace which is one of high-grade steel manufacturing apparatuses and a method of operating the same.

[Conventional Technology and Problems] As is well known, an electroslag remelting furnace (ESR furnace) immerses a consumable electrode in molten slag in a water-cooled mold,
The consumable electrode is melted by electric resistance heating generated in the molten slag, and the consumable electrode melts its tip sequentially by the heat and is dropped as molten droplets into the molten slag, and the dropped melt The droplets form a molten steel pool in a water-cooled mold, which is surrounded by a thin layer of solidified slag formed on the inner surface of the mold and solidified to sequentially form an ingot. Then, as the ingot grows, the water-cooled mold a is raised as shown in FIG. 3, and the ingot b is lowered while the water-cooled mold a is fixed as shown in FIG. There was a way to get there. 3 and 4, c is a consumable electrode, d is a support for the ingot b, e is molten slag accumulated in the water-cooled mold a, and f is a molten steel pool.

However, ingot b that can be ingot in any case
Was restricted to a certain length or less by the movable stroke of the water-cooled mold a or the movable stroke of the support base d.
For this reason, every time an ingot of a certain length was ingot, the dissolution was stopped, the ingot was removed, and then the ingot of the certain length was started again. Therefore, the problems listed below were encountered.

(1) For example, at the time of starting in the cold start method, it is necessary to place a starting material on the support base d and temporarily apply a large current to melt and raise the temperature as shown in FIG. Productivity deteriorates.

(2) Also, in order to eliminate the contraction hole in the upper part of the ingot as shown as a hot top in FIG. 5, the molten steel pool on the ingot must be cooled and solidified by gradually decreasing the current value before stopping the melting. The point was also a factor that reduces productivity.

[Object of the Invention] The present invention is intended to solve the above problems and to continuously form ingots to improve yield and productivity.

[Means for Achieving the Object] In order to achieve the object, the electroslag remelting furnace of the present invention comprises immersing a consumable electrode from above into molten slag accumulated in a cylindrical water-cooled mold, In the electroslag remelting furnace, the consumable electrode is melted by the generated electric resistance heating, and the ingot formed by solidification of the droplets is sequentially extracted from the lower opening of the water-cooled mold. Is provided with at least two grippers, and the ingots extracted from the water-cooled mold can be alternately gripped by the grippers, and at least one of the grippers is provided with a lifting means. It is what Further, the operating method of the furnace according to the present invention, in the furnace, while alternately gripping the ingot extracted from the water-cooled mold by the gripper, at least one of the grippers of the ingot while gripping the ingot. It is characterized in that it descends continuously or intermittently in accordance with the extraction speed, then lifts by separating the ingot, grips the upper part of the ingot again, and descends in the same manner as the above operation.

[Embodiment] Next, an embodiment of the present invention will be described with reference to FIGS. In the figure, 1 is a rectangular tube-shaped water-cooled mold supported on a pedestal 2, 3 is a consumable electrode suspended therein, and 4 is an ingot agglomerated in the mold 1. Support 2 of stand 2
a, 2a, 2b, 2b inside the linear bearings 5a, 5a,
5b and 5b are provided, and the grippers 6a and 6b are provided so as to be vertically movable along the support. Both grippers 6a, 6b
Is pivotally supported by supporting shafts 8a, 8a, 8b, 8b so that the pair of fingers 7a, 7a, 7b, 7b can be opened and closed respectively, and the tips of the fingers are opposed to both side surfaces of the ingot 4 and at the same time, Cylinders 9a and 9b are interposed between the other ends, and when the cylinders 9a and 9b are extended, the fingers are moved so that their tips hold the ingot 4. 10a and 10b are columns 2a and 2b
The upper and lower ends are parallel to the bearings 11a, 12a,
A screw shaft rotatably supported by 11b and 12b,
Reference numerals 13a and 13b are motors for rotating the screw shaft. Then, the screw shaft 10 is attached to the back of the grippers 6a and 6b.
Nuts 14a and 14b that are screwed into a and 10b are provided, and the screw shaft 10 is driven by motors 13a and 13b.
When a and 10b rotate, the grippers 6a and 6b move up and down.

In the thus constructed electroslag remelting furnace, the ingot 4 extracted from the lower opening of the water-cooled mold 1 is gripped by closing the fingers 7a, 7a of the one gripper 6a, and the extraction speed of the ingot is grasped. The rotation of the screw shaft 10a is controlled by the motor 13a so that the gripper 6a is lowered. And the gripper 6
Before a reaches the lower end of the vertical stroke, the fingers 7b, 7b of the other gripper 6b are closed to grip the ingot 4, and the gripper 6b is rotated by the motor 13b. The rotation lowers the ingot 4 to match the extraction speed of the ingot 4.
And the descending speed by the motor 13a are controlled to be the same. Further, the gripper 6a releases the grip of the ingot 4 in the meantime and reverses the screw shaft 10a to raise the gripper 6a to wait at the upper end of the vertical stroke.
Then, before the gripper 6b reaches the lower end of the vertical stroke, the gripper 6a is made to grip the ingot 4 again, and the ingot 4 is lowered at the extraction speed. In the meantime, the other gripper 6b releases the grip and reverses and raises the screw shaft 10b to wait at the upper end of the vertical stroke. Similarly, the ingot 4 is alternately held by the two grippers 6a and 6b, and the ingot 4 is lowered continuously according to the extraction speed. Note that the consumable electrode 3 is replaced in a timely and necessary manner. Therefore, according to this operating method, the ingot 4 is formed as long as necessary and can be cut into pieces with an appropriate length for use.

In this embodiment, the two grippers 6a and 6b are provided with the lifting / lowering means, but the lifting / lowering means is provided only on one gripper and the other gripper is fixed so as not to move up and down. You may comprise. That is, even if the fixed gripper holds the ingot only while the other vertically moving gripper moves up, and the ingot is guided downward only by one gripper, the ingot is continuously ingot-cast. In doing so, there is practically no major hindrance.

[Effects of the Invention] As described in the above embodiments, according to the electroslag remelting furnace and its operating method of the present invention, ingots are continuously agglomerated, which complicates starting and stopping. It is extremely useful because it eliminates the need for a special procedure, greatly improves productivity, and improves yield.

[Brief description of drawings]

1 is a longitudinal sectional view of an electroslag remelting furnace showing an embodiment of the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1,
3 and 4 are schematic diagrams for explaining a method of operating a conventional electroslag remelting furnace, and FIG. 5 is a diagram showing changes in the current value thereof. 1 ... Water-cooled mold, 3 ... Consumable electrode, 4 ... Ingot,
6a, 6b ... Gripping device, 10a, 10b ... Screw shaft, 1
3a, 13b ... Motor.

Claims (2)

[Claims] 1. A consumable electrode is immersed from above in a molten slag accumulated in a cylindrical water-cooled mold, and the consumable electrode is melted by electric resistance heating generated in the molten slag, and the droplet size thereof is In the electroslag remelting furnace in which the solidified ingot is sequentially extracted from the lower opening of the water-cooled mold, at least two grippers for gripping the ingot are provided, and the ingot extracted from the water-cooled mold is In addition to making it possible to alternately grip with a gripper,
An electroslag remelting furnace, wherein at least one of the grippers is provided with a lifting / lowering means. 2. A consumable electrode is immersed from above into a molten slag accumulated in a cylindrical water-cooled mold, and the consumable electrode is melted by electric resistance heating generated in the molten slag, and the droplet size thereof is In an electroslag remelting furnace in which solidified ingots are sequentially extracted from the lower opening of the water-cooled mold, the ingots extracted from the water-cooled mold are alternately gripped by at least two grippers, and At least one of the grippers descends according to the extraction speed of the ingot while gripping the ingot, then lifts by separating the ingot, and grips the upper part of the ingot again and descends according to the extraction speed of the ingot. A method of operating an electroslag remelting furnace, which is characterized in that