US2997756A - Method and apparatus for casting ingots - Google Patents

Description

Aug. 29, 1961 c. F. sTRoM METHOD AND APPARATUS FOR CASTING INGOTS Filed July 17. 1956 IN V EN TOR.

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2,997,756 METHOD AND APPARATUS FOR ICASTING INGOTS i Charles F. Strom, Glen Ellyn, Ill., assigner to Grilin Wheel Company, Chicago, Ill., a corporation of Delaare Filed July 17, 195'6, Ser. No. 598,414 5 Claims. (Cl. 22-69) This invention relates to a method and apparatus for making castings such as ingots and more particularly to a method and apparatus in which molten metal, such as steel, is forced under pressure into a mold.

An object of the invention is to provide la method of and apparatus for casting in which the metal constituting the casting is delivered to the mold without contact with an oxidizing atmosphere. In other words, the molten metal in a ladle may be conducted through a pouring tube and thence into the casting cavity of `a mold without exposure to or contact 'with air.

The invention embodies other novel features, details of construction and arrangements of parts which are hercinafter set forth in the specification and claims and illustrated in the accompanying drawing, which consists of an elevational View in cross section of an apparatus embodying the features of the present invention.

The apparatus for the pressure casting of ingots is shown as comprising a housing 2 having a cover 4 detachably secured thereon by means of bolts 6 to form a chamber 8 which receives a ladle 10 lled with molten metal 12, such as steel.

A tubular pouring spout 14 formed from a su-itable refractory material projects downwardly through an opening 16 in the cover 4 to terminate adjacent the bottom of the ladle 10. T-he pouring tube 14 has an upper flanged portion 17 which ts in lan opening provided in deck 18 and with deck 18 provides a flat surface upon which the -ingot mold 20 is positionable. The deck 18 being smooth permits the mold 20 to slide laterally thereon.

The deck 18 may be formed of copper, graphite or other suitable material and may have pipes (not shown) embedded therein for the circulation of liquid therethrough to maintain the deck in a relatively cool condition. This feature is described and illustrated in copending application No. 540,402, tiled October 14, 19'55, now abandoned.

rllhe upper end of the ingot mold 20 is closed by a feed head 21 comprising a cover 22 having Ia dome 24 and is detachably secured to the Imold 20 by means of bolts 26. A conical or triangular shaped projection 27 extends downwardly from the upper inner surface of the dome 24 and centrally thereof in order to obtain at atmospheric breakthrough into the dome so as to increase the eiciency of said feed head. A plurality of apertures 28 are formed in the dome 24 for the escape of gases therefrom.

The -feed head 21 is provided with an inner sandliner 30 as fully described in said copending application No. 540,402.

The top of the mold terminates in a flange 31 upon which is seated a heat resistant rubber sealing ring 32. The ring 32 is of approximately T-shaped cross section, one leg of which iits within the embracing arms of a vacuum bell 34. A tiexible noncollapsible pipe 36 establishes communication between the interior of the vacuum bell 34 and a source of vacuum 48.

rlhe sealed chamber 8 is in communication through inlet pipe 38 and pipe 40 not only with the source of vacuum 48 but also with a source of compressed gaseous medium, such as air or a nonoxidizing gas. A pipe 44 connected to the pipe 40 through a control valve 42 leads to a compressed air source, such as a pump (not shown).

nited States Patent i 2,997,756 Patented Aug. 29, 1961 ICE 51 for shutting off such communication when desired.

This pipe assures the existence of exactly the same pressure conditions in the vacuum bell and sealed chamber when the valve 51 is open.

Extending through the vacuum bell 34 and through the feed head 21 is an electrical wire 52 which terminates in an electrode 50 which establ-ishes Contact with the molten metal in the dome 24 and closes a circuit to ter- 1Lninate the delivery of compressed air to the sealed cham- In operation, the ladle filled with molten metal is positioned within chamber 8, and the cover 4 with pouring tube 14 in position is attached to the top of the chamber by the bolts 6. The at bottom of the mold 20 is then positioned upon the llat deck 18 and the flange 17 so that the gate 54 of hte mold is in registry with the opening 56 in the pouring tube 14. The vacuum bell 34 is then placed over the top of the mold which previously has been fitted with the feed head 21. Valve 42 is closed and valves 46 and 51 are opened. Under these conditions, both the vacuum bell and the sealed chamber are connected to the vacuum source which evacuates air from the sealed chamber 8, from the vacuum bell 34- and also from the interior of the mold 20. When a satisfactory vacuum is obtained, valves 46 and 51 are closed to terminate evacuation of air from the chamber 8 while maintaining and continuing subatmospheric pressure within the bell 34 and mold 20. Valve 42 is then opened to introduce gas under pressure into the sealed chamber to force the metal upwardly through the pouring tube 14 and into the mold 20.

The gas under pressure delivered to the chamber 8 through the inlet pipe 38 may be air or may be a nonoxidizing gas. The result, in either event, is that the metal which enters the mold proper from the ladle will have no` contact with atmospheric air. This operation can be employed either with a previously degassied ladle of molten steel ory with a normal heat of steel that has not been previously vacuum treated. In the latter event, the step of subjecting the mold and chamber to vacuum conditions will serve to degassify the molten metal in the ladle.

When the mold becomes iilled with molten metal and Such metal progresses upwardly to fill the space in the dome 24, the metal will contact the electrode 50 and thus activate an electrical circuit (not shown) which serves to slide the mold laterally so that the gate 54 is closed either by the flange 17 of the pouring tube or by the deck 18. Mechanism `for sliding the mold laterally upon termination of a pouring operation is described in said copending application No. 540,402. The electrical circuit mentioned in response to Contact by the metal with the electrode 50 also serves to terminate delivery of the gas under pressure to the chamber 8 `after the mold has been slid laterally. At this time the pressure within the chamber will be reduced to atmospheric pressure.

It will be understood that the invention may also be used in the production of other castings such as are commonly produced in a multi-part mold having a cope and drag |or otherwise divided into segments. Such a mold is disclosed in copending application Serial No. 236,324, tiled July l2, 1951, in the United States Patent Oce in the name of Edmund Q. Sylvester, now U.S. Patent No. 2,847,739. In producing such castings, the bell 34 contains the entire mold and is sealed around the bottom thereof as, for example, against the plate 18 or the cover plate 4 depending upon the detailed construction of the the present invention.

I claim:

1. In a pressure pouring apparatus of the type wherein liquid material is forced by the application of gas pressure thereagainst from a pressure chamber of a container to a mold disposed without the container, the combination of: means for transporting the material from said pressure chamber to the mold, a vacuum chamber overlying and engaging a portion of the mold, first means separate from said transporting means aiording direct communication between the respective chambers, said rst means including valve means, a vacuum source connected to said rst means at a place between said valve means and said vacuum chamber, a pressure source connected to said rst means at a place between said valve means and said pressure chamber, and other means separate from said transporting means and said first means also aiording direct communication between the respective chambers.

2. In a pressure pouring apparatus of the type wherein liquid material is forced by the application of gas pressure thereagainst from a pressure chamber of a container to a mold disposed without the container, the combination of: means for transporting the material from said pressure chamber to the mold, a vacuum chamber overlying and engaging a portion of the mold, a conduit independent of said transporting means directly interconnecting the respective chambers, another conduit independent of said transporting means and said rst mentioned conduit also directly interconnecting the respective chambers, each of said conduits including valve means, and vacuum source and pressure source conduits connected to said rst mentioned conduit between its valve means and the vacuum and pressure chambers, respectively.

3. 'In a pressure pouring apparatus of the type wherein liquid material is forced by the application of gas pressure thereagainst from a pressure chamber of a container to a mold disposed without the container, the combination of: means for transporting the material from said pressure chamber to the mold, a vacuum chamber overlying and engaging a portion of the mold, a conduit separate from said transporting means directly interconnecting the respective chambers, valve means in said conduit, a vacuum source connected to said conduit between said valve means and said vacuum chamber, a pressure source connected to said conduit between said valve means and said pressure chamber, another conduit directly interconnecting the respective chambers independently of said first mentioned conduit and said transporting means, and valve means in said other conduit.

4. In a method of pressure casting molten metal '4 wherein the metal is moved against the force of gravity by the force of superatmospheric pressure from a uid tight chamber of a container through a pouring tube, one end of which communicates with the metal, into the cavity of a mold disposed without the container, the steps of: providing another fluid tight chamber externally of the container and in communication with the mold cavity; providing a direct avenue of communication between the chambers which is independent of the pouring tube; exhausting both chambers independently of said avenue to provide equal subatmospheric pressure values in Said chambers; then closing said avenue of communication;

and then, while said avenue is closed, subjecting the rst mentioned chamber to superatmospheric pressure until the mold `cavity is lled.

5. In a method of pressure pouring molten metal from a chamber of an air-tight container against the force of gravity through a pouring tube into the cavity of a mold disposed without the container, the steps of: inserting said pouring tube into the container with the lower end of the tube extending into the metal; eecting an air-tight seal between the tube and the container around the tube; placing said mold over the container with its cavity in communication with the upper end of the tube; placing an airtight structure over a portion of the mold spaced from said tube to provide another chamber in communication with the mold cavity; providing a direct avenue of communication between the chambers which is independent of the pouring tube; exhausting both chambers from points thereof spaced from said avenue to provide equal subatmospheric pressure values in said chambers, then closing said avenue of communication; and then, while said avenue is closed, subjecting the iirst mentioned chamber to superatmospheric pressure until the mold cavity is lled.

References Cited in the le of this patent UNITED STATES PATENTS 969,539 Kitchen Sept. 6, 1910 1,029,565 Wetherill June 11, 1912 1,112,694 Grey Oct. 6, 1914 1,150,318 Wetherill Aug. 17, 1915 1,153,220 Grey Sept. 14, 1915 1,473,246 Montupet Nov. 6, 1923 1,703,739 Klepsch Feb. 26, 1929 1,910,008 Gray et al. May 23, 1933 2,401,491 Lyons June 4, 1946 2,625,719 Moore Jan. 20, 1953 FOREIGN PATENTS 27,619 Great Britain Dec. 17, 1904 455,258 Canada Mar. 22, 1949

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