US3866570A

US3866570A - Continuous casting apparatus

Info

Publication number: US3866570A
Application number: US475601A
Authority: US
Inventors: Santos Cruzado; Stanley Nicholas Dascaloff; John George Tolls; Eugene Fraley Torvend
Original assignee: General Electric Co
Current assignee: SWCC Corp
Priority date: 1973-06-28
Filing date: 1974-06-03
Publication date: 1975-02-18
Anticipated expiration: 1992-02-18

Abstract

Apparatus for a process of continuously casting metals by passing a metal core member upwardly through a container of molten metal, and thereby accreting and solidifying molten metal on the core member. The apparatus comprises a molten metal container or crucible with an entry port in its bottom wall for the passage of the core member. A bushing member is positioned within the entry port with a substantial portion of its mass extending above the inner surface of the bottom wall of the container and into its interior.

Description

United States Patent [191 Cruzado et al.

CONTINUOUS CASTING APPARATUS Inventors: Santos Cruzado, Bridgeport, Conn.;

Stanley Nicholas Dascalotf, Norristown, Pa.; John George Tolls, Southport; Eugene Fraley Torvend, Bridgeport, both of Conn.

General Electric Company, New York, NY.

Filed: June 3, 1974 Appl. No.: 475,601

Related US. Application Data Continuation of Ser. No. 374,331, June 28, 1973, abandoned.

[73] Assignee:

US. Cl. 118/405 Int. Cl. B05c 3/12 Field of Search 118/405, DIG. 18, DIG. 19. 118/420; 117/114 R, 114 A, 114 B, 114 C, 115, 51,52; l64/86,275

[56] References Cited UNITED STATES PATENTS 310,994 1/1885 Farmer 118/405 U X i 1 Feb. 18, 1975 910,674 1/1909 Hancock........ 164/86 2,216,519 10/1940 Ouarnstrom 118/405 U X 3,170,968 2/1965 Rokunohe et al. 118/405 U X 3,468,695 9/1969 Federman 118/405 X 3,700,486 10/1972 Veltri et al l13/405 X FOREIGN PATENTS OR APPLICATIONS 451,419 5/1968 Switzerland 164/86 Primary Examiner-Morris Kapllan Attorney, Agent, or Firm-R. G. Simkins; P. L. Schlamp; S. A. Young ABSTRACT 6 Claims, 2 Drawing Figures CONTINUOUS CASTING APPARATUS This is a continuation, of application Ser. No. 374,331, filed June 28, 1973, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to an improvement in apparatus for continuous metal casting, or the so-called dip forming process of metal casting. The apparatus includes a crucible or refractory container for molten metal which is provided with an entry port or orifice for the introduction and passage of a core member into the crucible or container and through the molten metal contained therein. A bushing member of refractory metal is inserted in the entry port or orifice to provide a relatively wear resistant seal about the moving core member.

The dip forming process of continuously casting by means of passing a core member upwardly through a crucible of molten metal, and apparatus therefor, is the subject of many prior US patents, including:

The disclosures of these U.S. patents are incorporated herein by reference.

The dip forming process of continuously casting as heretofore practiced and provided for by prior apparatus, incurred a serious defect in the form of the frequent occurrence of intermittent over-accretions or attachments of excessive and irregular accumulations of moltel metal on the moving core member. This phenomenon of aperiodic over-accretions on the core has been referred to in the art as belling, and the resultant excessive accumulations as bells," because of their physical resemblance to a bell-like configuration.

It is theorized that these irregularly occurring excessive accumulations along the core member are the result of uneven thermal conditions in the bottom portion of the interior of the crucible or molen metal container. Uneven temperature conditions are believed to foster the freezing or partial freezing of molten metal to a semi-solid or mushy and stagnant state in the bottom of the crucible in an area adjacent the inlet port.

It appears that the freezing or semi-solidification of portions of the melt proceeds until the build up of one or more bodies of solid or semisold material becomes large enough to extend into the sphere of the accretion onto the core member, and its mass or a portion thereof abruptly adheres to the core member in the form of an oversized accumulation of metal or bell. The occurance of this phenomenon during the continuous casting process is often evidenced by sharp jolts in the apparatus within the region of the crucible, apparently due to an abrupt breaking or tearing away of an attached body of solidified or partially solidified melt by the rapidly moving core member, or the passage of an oversized accumulation fused to the core member through the exit portal of the apparatus.

The intermittent violent jolting encountered, which is evidently due to this so-called belling phenomenon, is detrimental to the casting apparatus as well as the product because the repeated physical shocks accelerate deterioration of refractory components. Moreover,

this adverse phenomenomcan occur in very frequent intervals of from one to ten seconds.

SUMMARY OF THE INVENTION This invention comprises an improvement in apparatus for carrying out a continuous metal casting or dip forming process comprising passing a core member upwardly through a crucible containing molten metal, which substantially eliminates the occurrence of overaccretions or excessive and irregular accumulations, or so-called bells, on the core member.

The improvement of this invention includes positioning the bushing member for the entry port in a lower region of the molten metal crucible located below the surface of the molten metal so that a substantial portion of the end of the bushing member extends in beyond the inside surface of the crucibles wall and continues into the crucibles interior.

OBJECTS OF THE INVENTION A primary object of this invention is to provide an ap paratus for continuously casting metal which effectively inhibits the occurrence of over-accretions or the attachment of excessive and irregular accumulations of metal on the core member, and thereby produces a uniform cast product.

Another object of this invention is to extend production runs and performance life of continuous casting manufacturing equipment, and to reduce maintenance and downtime for repairs by eliminating the adverse effects upon manufacturing equipment incurred with the formation of over-accretions or the attachment of excessive and irregular accumulations of metal to the core.

A further object of this invention is to provide means which facilitate a uniform casting operation and the formation of a cast product of regular dimensions.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a view of a novel apparatus constructed in accordance with one embodiment of this invention shown in cross-section, with the core member and cast product shown in elevation; and,

FIG. 2 is an enlarged detailed view of a portion of the apparatus of FIG. 1 shown in cross-section, with the core member and cast product shown in elevation.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Referring to the drawing, a metal core member 10, such as a rod of copper, is continuously passed upwardly through the apparatus of the continuous casting system 12. The core member can be moved through the apparatus by appropriate drive means such as feed rolls l4 and 14', and take up rolls l6 and 16'. Core member 10 is preferably first passed through an annular cutting die 18 which continuously shaves off a portion of the outer surface of the core member to eliminate surface oxides or contaminants and to provide a clean metal face for the adherence of the molten metal. Other means, such as an acid pickling bath, can serve to effectively clean the surface of the core member. However, the annular cutting die 18 is a preferred means because, among other reasons, it also performs a sealing function at the system entrance.

Passing from the cutting die 18, the shaved and cleaned core member 10 enters a vestibule chamber 20, which is preferably evacuated, such as through pipe 22, to minimize exposure of the shaved core member to oxygen and other air borne contaminants.

Crucible 24, comprising a suitable refractory vessel for the containment of molten metal 26, such as copper, is preferably enclosed to protect its content from the atmosphere. Crucible 24 is provided with an entry port or orifice 28 located in its bottom wall 30 below the surface of its molten metal contents for passage therethrough of the core member upwardly into the crucible chambers interior, and through its contents of molten metal 26. A bushing member or insert 32 formed of a refractory material such as hightemperature resistant metal, is provided within the entry port 28 of the crucible 24, and in accordance with one preferred embodiment of the invention, the bushing member extends from the vestibule chamber to the crucible 24 substantially as shown in the drawing.

In accordance with this invention, and as shown in detail in FIG. 2, bushing member or insert 32 is positioned within the entry port 28 with a substantial portion of its upper end 34 and mass extending into the crucible chamber above the inner surface or floor of the bottom wall 30 of the crucible substantially as shown. In accordance with a preferred embodiment of the invention, the bushing member 32 extends above the inner surface of the crucible bottom wall for a.-

distance of at least about one-fourth inch, for example for a distance approximately ranging from about onefourth to about one-half inch.

It has been discovered that this positioning of the bushing member 32 or insert with its end 34 projecting up above the inner surface of the crucible bottom wall and extending into the interior of the crucible, virtually eliminates the troublesome and frequent occurrence of bells comprising over'accretions or the attachment of excessive and irregular accumulations of molten metal on the core member in a continuous casting process.

On passing through the bath of molten metal 26 with the apparatus of this invention, the relatively cold core member 10 progressively accretes over its surface a substantially uniform and flaw-free accumulation of solidifying melt. The upward moving core member thus acquires and carries fromthe molten bath an evenly adhering mass of cast metal on its surface and intergrally joined therewith.

After passing through the bath of molten metal 26 and accreting thereon a mass of solidified molten metal, the core member passes out of the crucible 24 up through an exit port 36 or orifice in the top wall 38 of the crucible 24. Upon exiting from the crucible chamber, the cast product moves through a water spray 40, or other suitable cooling means, to reduce the temperature of the cast product.

Prior to this invention an excessive number of bells on the cast product were routinely observed after very short periods of production of about l0 hours, and sometimes bells occurred shortly after commencing a production run. With the end of the bushing member projecting a distance of from about one-fourth to onehalf inch above the crucible bottom wall and extended into the crucible chamber pursuant to this invention, bells were virtually eliminated from the cast product, even after prolonged periods of hours or more of production. Moreover the previously encountered sharp jolts, which were associated with the occurrence of bells, were no longer observed.

Although copper has been mentioned in the foregoing description of an embodiment of this invention, the apparatus of this invention is useful in the casting of other metals. For example, the invention can be used in the casting of substantially any metal or alloy upon a core member composed of the same metal or alloy as the melt, or a different metal or alloy, and may include plating or encasing operations.

Although the invention has been described with reference to a certain specific embodiment thereof, numerous modifications are possible and it is desired to cover all modifications falling within the spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for the continuous casting of meatls comprising copper by passing a metal core member comprising copper upwardly through a crucible containing molten metal comprising copper and thereby accreting and solidifying molten metal comprising copper on the core member, comprising the combination of: a crucible for the containment of molten metal comprising copper having an entry port below the surface of said molten metal for the passage of a metal core member comprising copper into the crucible and through the contents thereof, a vestibule chamber positioned adjacent to the crucible entry port, and a refractory metal cylindrical bushing member extending from within the vestibule chamber to the crucible having a cylindrical end inserted into and positioned within said entry port of the crucible and extending for a distance of about one-fourth to about one-half inch above the crucible bottom wall into the crucible.

2. The apparatus of claim 1, wherein the entry port is located in the bottom wall of said crucible.

3. Apparatus for the continuous casting of metal comprising copper by passing a metal core member comprising copper upwardly through a crucible containing molten metal comprising copper and thereby accreting and solidifying molten metal comprising copper on the core member, comprising the combination of: a crucible for the containment of molten metal comprising copper having a bottom wall provided with an entry port for the passage of ametal core member comprising copper into the crucible and through the contents thereof, a vestibule chamber positioned adjacent to the crucible entry port, and a refractory cylindrical bushing member extending from within the vestibule chamber to the crucible having a cylindrical end inserted up into and positioned within said entry port of the bottom wall of the crucible and extending for a distance of about one-fourth to about one-half inch above the crucible bottom wall into the crucible.

4. Apparatus for the continuous casting of metals comprising copper by passing a metal core member comprising copper upwardly through a crucible containing molten metal comprising copper and thereby accreting and solidifying the molten metal comprising copper on the core member, comprising the combination of: a crucible having enclosing walls defining a closed chamber for the containment of molten metal comprising copper, said crucible walls including a bottom wall provided with an entry port and a top wall provided with an exit port for the passage of a metal core member comprising copper up through the closed crucible chamber and the contents thereof; a vestibule chamber positioned adjacent to the crucible entry port; and, a refractory metal cylindrical bushing member extending from within the vestibule chamber to the closed crucible chamber having a cylindrical end inserted up into and positioned within said entry port of the bottom wall of the crucible and having a portion of its cylindrical end extending for a distance of about one-fourth to about one-half inch above the crucible bottom wall into the closed chamber of the crucible.

5. Apparatus for the continuous casting of copper by passing a copper metal core member upwardly through a crucible containing molten copper and thereby accreting and solidifying molten copper on the core member, comprising the combination of: a crucible having enclosing walls defining a closed chamber for the containment of molten copper, said crucible walls including a bottom wall provided with an entry port and atop wall provided with an exit port for the passage of a copper coremember up through the closed chamber ofthe crucible and the molten copper contents thereof; a vestibule chamber positioned adjacent to the crucible entry port; and, a refractory bushing member extending from within the vestibule chamber to the closed crucible chamber having an end inserted up into and positioned within said entry port of the bottom wall of the crucible and having a portion of its end extending for a distance of about one-fourth to about one-half inch above the crucible bottom wall into the closed chamber of the crucible and the molten copper contents thereof 6. The apparatus of claim 5, wherein the bushing member comprises refractory metal.

Claims

5. Apparatus for the continuous casting of copper by passing a copper metal core member upwardly through a crucible containing molten copper and thereby accreting and solidifying molten copper on the core member, comprising the combination of: a crucible having enclosing walls defining a closed chamber for the containment of molten copper, said crucible walls including a bottom wall provided with an entry port and a top wall provided with an exit port for the passage of a copper core member up through the closed chamber of the crucible and the molten copper contents thereof; a vestibule chamber positioned adjacent to the crucible entry port; and, a refractory bushing member extending from within the vestibule chamber to the closed crucible chamber having an end inserted up into and positioned within said entry port of the bottom wall of the crucible and having a portion of its end extending for a distance of about one-fourth to about one-half inch above the crucible bottom wall into the closed chamber of the crucible and the molten copper contents thereof.

6. The apparatus of claim 5, wherein the bushing member comprises refractory metal.