US3523995A - Installation for casting metal with the electroslag refining thereof - Google Patents

Description

N. A. TULIN ETAL Aug. 11, 1970 3,523,995 I INSTALLATION FOR CASTING METAL WITH THE ELECTROSLAG REFINING THEREOF 2 Sheets-Sheet 1 Filed Feb. 28, 1967 INVENTORS ATTORNEYS Nikolai, fllfilinplaa Aug. 11, 1970 N. A. Tu' ETAL 3,523,995

INSTALLATION FOR CASTING -AL H THE ELECTROSLAG REFINING THER 7 Filed Feb; 28, 1967 2 Sheets-Shee12 1/x /27- i (H) 20 F '1 4 TI 4 V 0' Z 4\,% H63 United States Patent Office 3,523,995 Patented Aug. 11, 1970 3,523,995 INSTALLATION FOR CASTING METAL WITH THE ELECTROSLAG REFINING THEREOF Nikolai Alexeevich Tulin, Ul. Stalevarov 36-A, kv. 42;

Nikolai Fedorovich Bastrakov, Ul. Bogdana Khmelnitskogo 27, kv. 50; Alexandr Yakovlevich Silaev, Ul- Stalevarov 15, kv. 39; Vitaly Semenovich Pismenov, U]. 3 Sputuika 3, kv. 34; Ljudmila Viktorovna Krivtsova, U1. 3 Sputnika 30, kv. 67; Gennady Vasilievich Gutara, Ul. Rumyantseva 36, kv. 36; Leonid Grigorievich Pritulyak, Ul. Kommunisticheskaya 6, kv. 38; Viktor Savelievich Borodin, Ul. Degtyareva 47, kv. 62; and Igor Denisovich Donets, Ul. Rumyantseva 46, kv. 22, all of Chelyabinsk, U.S.S.R. Filed Feb. 28, 1967, Ser. No. 619,298 Int. Cl. B22d 27/02 US. Cl. 164-252 4 Claims ABSTRACT OF THE DISCLOSURE An installation for casting metal with the electroslag refining thereof including a vertically movable mold and a hollow non-consumable electrode having a lined metal conduit for the molten metal that can be readily replaced.

The present invention relates to metallurgical and machine-building industries, and more particularly to installations for casting metal with electroslag refining thereof.

Known at present is an experimental installation designed for effecting a method of electroslag casting of ingots, comprising a ladle with liquid metal, a hollow non-consumable electrode, and a mold complete with a bottom plate. The experiment was conducted in the following manner. The slag mixture was poured into the mold, wherein it was melted down by applying current to the bottom plate and electrode.

Then the mixture was overheated, and the molten metal was supplied through the cavity of an electrode immersed in the slag. As the mold filled with metal and the ingot was formed therein, the non-consumable electrode was withdrawn from the mold (see the Inventor's Certificate No. 168,743, U.S.S.R.).

The raising of the electrode, however, must be elfected simultaneously and synchronously with the lifting of the ladle, thereby continuing to cast the molten metal into the mold through the electrode cavity. There have been observed cases in which the stream of metal touched the walls of the electrode cavity, resulting in short-circuiting or freezing of metal on the walls of the electrode cavity, which was conductive to a narrowing of the electrode channel. This fact required the replacement of the electrode. Moreover, the electrode of a tubular shape, made completely of graphite, did not possess a sufiicient mechanical strength and electrical conductivity. The supply of current was effected to the cylindrical portion of the electrode by means of tongs which also serve for retaining the electrode in position.

The installation was provided with a guiding column along which, during the formation of an ingot and its withdrawal from the mold, carriages of the electrode and mold were displaced vertically.

An object of the present invention is to eliminate the above disadvantages.

The principal object of the present invention is to provide an installation for casting metal with an electroslag refining thereof, said installation having a greater productive capacity, permitting the improvement of the quality of ingots obtained thereby, excluding the necessity of lifting the ladle during the operation of pouring metal therefrom into the mold, and a stronger electrode having an improved supply of current, with the electrode ensuring a decrease in the electric power losses, as well as longer use.

This object is accomplished due to the provision of an installation for casting metal with an electroslag refining thereof in a cooled mold complete with a bottom plate and a non-consumable electrode, wherein the electrode is secured on a metal, current-carrying framework, while inside the electrode and metal framework there is inserted a detachable metal conduit of tubular shape made of a refractory material which is not electrically conductive.

The installation may be provided with a framework, to whose flat surfaces flat bus bars are attached supplying current to the electrode.

The installation may be provided with a detachable metal conduit having a funnel in its uppermost portion, as well as with the electrode framework having a socket for retaining the funnel.

The installation may be provided with a metal conduit assembled of annular members enclosed in a metal jacket.

The nature of the present invention will become more fully apparent from a consideration of the following description of an exemplary embodiment thereof, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a general view of the installation of the present invention;

FIG. 2 is a plan view of the installation;

FIG. 3 shows parts of the installation by partial longitudinal sectional views;

FIG. 4 represents the electrode of FIG. 3 in a crosssectional view taken along the line 44 of FIG. 3.

The installation is provided with two cooled molds 1 and 1' (FIGS. 1 and 2) complete with corresponding bottom plates 2 and 2' and hydraulic drives 3 and 3' for the mutual displacement of each mold and bottom plate. An electrode 4 secured on a bracket 5 is displaced by means of a carriage 6 movable along a vertical column 7. A pneumatic drive 8 is provided to draw off the electrode 4 on the bracket 5.

Pneumatic cylinders 9 and 9 turn the molds 1 and 1' in the horizontal direction, while mechanisms 10 and 10' fix the molds when stripping ingots.

The electrode 4 which is non-consumable graphite is secured on a metal current-carrying framework 11.

A detachable metal conduit (FIG. 3) is inserted within the electrode 4 and framework 11. It will be noted that the conduit 12 includes a metal jacket of tubular form having a funnel 16 secured at its upper end while a tube and funnel of a refractory non-electrically conductive material are inserted respectively into the jacket 14 and funnel 16. The refractory tube may be either monolithic or assembled of a plurality of annular members 13-.

The metal conduit 12 is freely inserted into the framework 11 which is provided with a socket 15 for retaining the funnel 16 of the metal conduit 12.

In order to replace the metal conduit 12, the conduit is displaced upwardly by a suitable hoisting means and in order to permit such an operation to be affected, projections are provided on the upper portion of the funnel 16 as clearly illustrated in FIG. 3. Such an embodiment of the electrode enables an easy and rapid replacement of the metal conductive component, namely, metal com duit 12 without the necessity of disassembling the current carrying components constituting the electrode.

The tube and funnel of refractory material are easily withdrawn from the jacket 14 and the funnel 16 respectively following the detachment of the rings along the line of coupling of the jacket 14. Thereafter, a new tube and funnel of refractory material are inserted into the jacket 14 and the rings along the line of uncoupling are drawn up. The thus assembled metal conduit 12 is lowered through the socket 15 into the current carrying frame-v work 11. The provision of a spare conduit 12 renders it possible to replace the refractory tube and funnel in advance and thereby prepare the metal conduit for the expected replacement.

The framework 11 has flat surfaces on opposite sides denoted 17 and 17' to which are attached flat bus bars 18 for supplying electric current to the electrode 4. The middle portion of the electrode is provided with a sleeve 19 and a wedge 20 cooperable therewith for connecting the framework 11 with the graphite terminal 4.

Along the uncoupling line of the jacket 14 are provided rings 21 for tightening the sides of the jacket.

A casting ladle is provided to supply the molten metal, and a crane (not shown) is provided for movement of the ladle and disposal of the ingot.

The installation operates as follows:

The electrode 4 complete with the metal conduit 12 enclosing refractory conduit 13, being secured on the bracket 5, is placed in the working position. A starter bar on which a self-igniting slag is poured is placed on the bottom plate 2 secured on the hydraulic drive 3. The term self-igniting slag has reference to a small amount of slag poured for priming and serving to form the initial slag, namely, the small amount of molten slag which initiates the melting of the slag mixture (the main slag). The mold 1 is placed on the bottom plate 2, and the electrode 4 is brought to the self-igniting slag, upon which the slag mixture or main slag is poured therein, and current is supplied to the bottom plate 2 and electrode 4 from a power transformer (not shown).

When current passes through the self-igniting slag, the slag mixture is melted down by the heat evolved thereby. Thereafter, the ladle with the molten metal is brought to the installation.

The ladle tap hole is disposed at the funnel 16- of the metal conduit 12., and the molten metal is poured through the tap hole into the mold 1. The mold 1 together with the bottom plate 2 is lowered by means of the hydraulic drive 3 as the mold is filled with the molten metal.

In the process of casting, current is supplied to maintain the slag temperature at a level of 1700 to 2000 C.

The casting is thereby effected through a layer of molten slag, thereby ensuring the oriented crystallization and refining of the molten metal at the expense of a highly heated slag. As a result, an ingot with a dense structure without any faults is obtained, which is cleaner with regard to non-metallic inclusions and has a minimum content of sulphur and gases.

Upon completing the casting operation, the upper portion of the ingot continues to be heated so as to eliminate the shrinkage cavity, after which the current is disconnected. The electrode 4 is withdrawn from the mold 1, and then the electrode 4 is drawn olf by the pneumatic drive 8 from the working position. Upon solidification of the ingot, the mold 1 together with the bottom plate 2 and ingot are lifted by means of the hydraulic drive 3, and the position of the mold 1 is fixed by element 10, upon which the bottom plate 2 together with the ingot is lowered, thus effecting the stripping of the ingot.

The mold 1 thus emptied is drawn aside by means of the pneumatic drive 9 in such a manner as to enable the stripped ingot to be removed from the bottom plate by the aid of the crane.

This terminates the casting and refining of an ingot of the molten metal.

The installation is provided with a second mold 1 complete with a bottom plate 2' and hydraulic drive 3, all of which is required to pass over to the casting into mold 1' after disconnecting current upon completing the casting into the first mold 1. Before starting casting into the mold 1', the metal conduit 12 is to be replaced with a view of preventing the metal, frozen on the metal conduit walls, from closing the metal flow passage during the repeated casting into the mold 1 or 1', and thus impairing the quality of the ingot obtained. It is sufficient to replace the refractory tube and funnel for the metal conduit so as to enable it to be used for the second time.

The operations of casting and refining of metal in the mold 1' are repeated similarly to those carried out in the mold 1.

What is claimed is:

1. An installation for casting metal with the electroslag refining thereof, comprising a cooled mold having a bottom plate, a hollow non-consumable electrode insertable in the mold, a bracket for the installation, a metal current carrying framework for the electrode secured to the bracket, a hollow graphite discharge terminal for the electrode retained in position by the framework, and a detachable conduit for said electrode, said detachable conduit comprising inner and outer tubular components, a funnel portion at the upper part of each component, the inner component and its funnel portion being of refractory material possessing non-electrical conductive properties, and the outer component and its funnel portion being of metal.

2. The casting installation as claimed in claim 1 in which said framework is provided with planar surfaces to which flat bus bars are attached for supplying current to the electrode.

3. The casting installation as claimed in claim 1 in which said framework for said electrode is provided with a socket for retaining the detachable conduit by the funnel portion at the upper part of the outer tubular component.

4. The casting installationas claimed in claim 1 in which said inner component is constituted by annular members of refractory material possessing non-electrical conductive properties.

References Cited UNITED STATES PATENTS 1,679,284 7/1928 Westly 1318 X 1,912,560 6/1933 Wiles 13-18 2,380,109 7/1945 Hopkins 16452 2,686,822 8/1954 Evans et al 164252 X 3,106,596 10/1963 Smallridge et a1 13-18 FOREIGN PATENTS 135,344 11/ 1949 Australia.

OTHER REFERENCES Alloys Made by Electric Ingot Process Have Improved Properties, by H. R. Clauser, Materials & Methods, January 1948, pp. 57-61.

I. SPENCER OVERHOLSER, Primary Examiner V. K. RISING, Assistant Examiner US. Cl. X.R. 1318, 33, 35

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