US3620287A

US3620287A - Method of producing ingots, in particular, slab ingots, by electroslag remelting of consumable electrodes

Info

Publication number: US3620287A
Application number: US42913A
Authority: US
Inventors: Boris Izrailevich Medovar; Vitaly Mikhailovich Baglai; Albert Nikolaevich Sevruk; Jury Vadimovich Latash
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-06-03
Filing date: 1970-06-03
Publication date: 1971-11-16
Anticipated expiration: 1988-11-16

Abstract

This disclosure relates to a method of producing ingots, in particular, slab ingots, by electroslag remelting of consumable electrodes. The method according to the present invention consists in the introduction to a cooled crystallizer of two groups of consumable electrodes, each of said groups comprising one electrode, stationary with respect to the crystallizer, and at least one movable electrode, which helps ensure a high quality of slab ingots produced. This method can be most advantageously used for producing slab ingots intended for direct sheet rolling without the use of powerful cogging means.

Description

United States Patent 8/1946 Hopkins .l l64/252UX FOREIGN PATENTS 1,448,656 6/1966 France Primary Examiner.i. Spencer Overholser Assistant Examiner-John E. Roethei Attorney-Holman & Stern I ABSTRACT: This disclosure relates to a method of producing ingots, in particular, slab ingots, byelectroslag remeiting of consumable electrodes.

- The method according to the present invention consists in the introduction to a cooled crystailizer of two groups of consumable electrodes, each of said groups comprising one electrode, stationary with respect to the crystallizer, and at least one movable electrode, which helps ensure a high quality of slab ingots produced.

This method can be most advantageously used for producing slab ingots intended for direct sheet roiling without the use of powerful cogging means.

[21] Appl. No. 42,913 [22] Filed June 3, 1970 [4S] Patented Nov. 16, 1971 [54] METHOD OF PRODUCING INGOTS, IN

PARTICULAR, SLAB INGOTS, BY ELECTROSLAG REMELTING 0F CONSUMABLE ELECTRODES 5 Claims, 2 Drawing Figs.

52 us. Cl 164152, 164/252 [51] Int. Cl B22d 27/02 50 Field of Search 164/52, 252

[56] References Cited UNITED STATES PATENTS 1 2,191,478 tH9Rk F ""t'rr'":':':""i':

METHOD OF PRODUCING INGO'IS, IN PARTICULAR, SLAB INGOTS, BY ELECTROSLAG REMELTING F CONSUMABLE ELECTRODES The present invention relates to the field of electrometallurgy and, more particularly, it relates to a method of production, by electroslag remelting of consumable electrodes, of ingots, in particular, slab ingots intended for direct sheet rolling.

Known in the art is a method of producing slab ingots by electroslag remelting in a cooled crystallizer of two groups of movable consumable electrodes connected in series to the secondary winding of a single-phase feeding transformer (cf., Belgian Pats. No. 670,299, priority date 29th Sept., 1965, and No. 707,566, priority date 5th Dec., 1967).

However, when producing slab ingots by the latter known method, possible burns of the crystallizers are to be avoided resulting from the contact of the crystallizer walls with the movable electrodes which, with their buming-off, are fed to the crystallizer, to which end the cross section of the consumable electrodes has to be reduced, particularly the dimension thereof corresponding to the narrow face of the slab ingot, and the electrode length increased, which causes difficulties in the manufacture of such electrodes and complicates the design of the equipment.

There is likewise known a method of producing ingots by way of electroslag remelting in a cooled crystallizer of stationary consumable electrodes (cf., Belgian Pat. No. 711,199, priority date 23rd Feb., 1968).

Such a method of producing slab ingots can preclude the possibility of the crystallizer burns, provide for a high degree of filling the crystallizer sectional area and, consequently, for reducing the height of the plant, however, it is impossible to produce a slab ingot of considerable length due to an excessive increase in the depth of the slag bath by the end of meltmg.

For example, when employing the last-mentioned known method of producing a slab ingot with a l40Xl,500 mm. section and 2 m. long, the minimum possible rated increment of the depth of the slag bath by the end of melting is equal to 360 mm., which is by no means tolerable due to a sharp deterioration of the quality of metal in the ingot.

It is an object of the present invention to eliminate the above-mentioned disadvantages.

The main object of the present invention is to provide a method of producing ingots, in particular, slab ingots, by electroslag remelting of consumable electrodes, whereby the melted metal from the ends of consumable electrodes is supplied to the slag bath simultaneously over the whole crystallizer width, which provides for a high quality of slab ingots produced.

In the accomplishment of said object of the invention, in a proposed method of producing ingots by way of electroslag remelting in a cooled crystallizer of two groups of consumable electrodes connected in series to the secondary winding of a single-phase transformer, according to the invention, each group of consumable electrodes is composed of at least one electrode, stationary with respect to the crystallizer and serving to introduce the main portion of metal to the slab ingot being produced, and at least one movable electrode serving to maintain and regulate the melting process and connected in parallel to the stationary electrode.

It is expedient that the movable consumable electrodes be arranged in the crystallizer between the stationary electrodes or on the outer sides of the latter.

In order to reduce the length of the bumt-off portion of the movable electrodes, it is expedient that the remelting process be carried out with the addition of small amounts of solid flux to the crystallizer.

For increasing the weight of the slab ingot without increasing the length of the movable electrodes in the course of remelting it is possible to repeatedly replace the movable consumable electrodes.

The method carried out in accordance with the present invention helps successfully solve the problem of the invention, features an increased reliability of electroslag remelting process and provides a possibility of regulating the process for remelting.

For a better understanding of the method of the invention, presented hereinbelow is a detailed description of an examplary embodiment thereof, 'due reference being had to the accompanying drawings, wherein:

FIG. 1 shows schematically in plan view a possible arrangement of groups of consumable electrodes in a cooled crystallizer, and a single-phase transformer feeding them; and

FIG. 2 illustrates a general view of a plant for electroslag remelting to produce ingots, in accordance with the method of the invention.

Now, referring to FIGS. 1 and 2, a cooled crystallizer 1 accommodates two groups of electrodes, each of said groups comprising a stationary consumable electrode 2 and a movable consumable electrode 3. The groups of consumable electrodes are connected in series to a secondary winding 4 of a single-phase feeding transformer 5, the electrodes 2 and 3 in each group being connected to each other in parallel. in addition, with a view to additional stabilization of the buming-off process of the stationary consumable electrodes 2, the middle point 0 of the secondary winding 4 of the transformer 5 can be electrically connected to a slab ingot 7 being produced (in FIGS. 1 and 2 such connection being shown with a dashed line). In the embodiment illustrated in FIGS. 1 and 2 the movable electrodes 3 are arranged between the stationary electrodes 2, however, the movable electrodes 3 can be also arranged on the outer sides of the stationary electrodes 2. With the buming-off of the movable electrodes 3, the level of a slag bath 6 is shifted upwards 'so that the ends of the stationary electrodes 2 stay immersed to a certain measure in the slag bath 6. When so doing, the greater part of the working current passes in the circuit of the stationary electrodes 2. Melted metal from the ends of the consumable electrodes 2 and 3 is supplied to the slag bath 6 simultaneously over the whole width of the crystallizer I, which provides for a high quality of the slab ingot 7 being produced. By varying the rate of feed of the movable electrodes 3, it is possible to regulate the total working current and the degree of immersion in the slag bath of the stationary electrodes 2. The main portion of metal is introduced to the slab ingot 7 being produced by the stationary electrodes 2, while the movable electrodes 3 mainly serve to maintain and regulate the process of remelting. In order to reduce the length of the burnt-off portion of the movable electrodes 3, to the crystallizer 1 in the course of melting, solid flux is added which while melting, increases the height of the slag bath 6, that is, displaces upwardly the surface of the slag bath. Charging the solid flux in the course of melting makes for replacing the movable electrodes 3 without interrupting the melting process since, at the moment of replacing the electrodes 3, the melting process is maintained owing to the melting of the solid flux being charged. The amount of solid flux charged to the crystallizer l in the course of melting should be such that, by the end of melting, the depth of the slag bath do not exceed the permissible value, say, 1.5-2 times the width of the narrow face of the crystallizer.

The hereinabove described method of producing slab ingots by way of electroslag remelting of consumable electrodes helps produce slab ingots intended for direct sheet rolling without the use of powerful cogging means.

We claim:

1. A method of producing ingots, mainly slab ingots, by way of electroslag remelting of consumable electrodes, comprising introducing to a cooled crystallizer two groups of consumable electrodes connected in series to the secondary winding of a single-phase transformer, each of said groups of consumable electrodes comprising, parallel interconnected, one electrode, stationary with respect to the crystallizer and serving to introduce the main portion of metal to the slab ingot being produced, and at least one movable electrode serving to maintain and regulate the process of remelting.

2. A method as set forth in claim I, wherein said movable consumable electrodes are arranged in the crystallizer between said stationary electrodes.

3. A method as set forth in claim 1, wherein said movable electrodes are arranged in the crystallizer on the outer sides of said stationary electrodes.

4. A method as set forth in claim 1, wherein, with a view to increasing the weight of the slab ingot without increasing the length of the movable electrodes, said movable electrodes are

Claims

2. A method as set forth in claim 1, wherein said movable consumable electrodes are arranged in the crystallizer between said stationary electrodes.

4. A method as set forth in claim 1, wherein, with a view to increasing the weight of the slab ingot without increasing the length of the movable electrodes, said movable electrodes are replaced in the course of remelting.

5. A method as set forth in claim 1, further comprising adding solid flux to said crystallizer during remelting, whereby the length of the burnt-off portion of said movable electrodes may be reduced.