US1815186A - Method of casting metals - Google Patents

Description

July 21, 1931. H. L. COLES 1,815,186

Patented July 21 1931 UNITED STATES PATENT OFFICE HENRY L. COLES, OF HAMILTON, OHIO, ASSIGNOB TO GUARDIAN METALS OOMPAN'Y, OF HAMILTON, OHIO, A COBI'ORATION- OF DELAWARE METHOD or cas'rme mn'rans Application filed February 20, 1929, Serial No. 941,381. Renewed January 12, 1931.

This invention relates to metal founding, and more particularly to an improved method of producing shrinkless castin s of metals '01 alloys having a relatively hig coeflicient of expansion.

As is well known, molten metals decrease in volume on cooling, the shrinking of such metals in a mold after casting, causing grave inconveniences due to the surfaces of the'cast body being considerably depressed and the corners rounded or shrunken. To prepare such castings in a condition for use, it is necessary to chip out the shrunken faces and replenish the missing metal with fresh,-

molten metal. This latter procedure is not only costly, involving considerable expense in both time and labor, but the results are not uniform, and the process may have to be repeated in order to securepassa 1e castings.

The deficiencies met with in the practice of metal founding, are marked in ferrous castings, and even more in non-ferrous castings.

This is due to the fact that the non ferrous.

the formation of shrink holes, or depressions,

or the like.

Yet another object of this invention is the provision of an improved means for securing shrinkless castings.

These and other desirableobjects and advantages of the present invention will be described in the accompanying specification and illustrated in the drawings, a preferred embodiment being given by way of illustration only, for since the; underlying principles may be applied to other specific processes, it is not intended to be limited to the one herein shown, except as such limitations are clearly imposed by the appended claims.

Fi 1 represents a vertical cross section of a ottom pour mold, showing the applicawell known to those skilled in the art.

tion of the principles of the present invention.

Fig. 2 is a view similar to Fig. 1 showing the application of the present invention to the top pour mold, and Fig. 3 isa vertical cross section of an ingot showing the difiiculties usually encountered in ordinary cast- Tn the practice of the invention, a mold of suitable form is provided, preferably of the bottom pour type. This structure may comprise a bottom portion or drag 1, having sides 2 and floor 3, with or without a bottom pouring gate 4, the construction of whic%fis e drag is rammed up in the usual mannenwith molding sand or any other suitable material, indicated generally at 5, and the pattern withdrawn, after the cope 6 prepared in the same manner, is finished. uitable luting 7, may be provided between the cope and drag. The materials used and their manner of application are well known to those skilled in the art and need no further explanation here. k

As has been stated hereinbefore, the major difiicult met with in castin metals to form, is the s rinkage-zresulting IOIIl the cooling of the metal, with a resulting deformation of the surfaces of the casting. This difficulty has now been overcomeby the discovery that the initially chilled skin of the casting may be held in place by providing suitable supports 8 in the cope or walls. These members may be of any suitable dimensions, and preferably are of suflicient length to protrude through the cope and walls and into the casting chamber 9, for a considerable distance.

As the molten metal rises through the gate l and into chamber 9, it contacts with the members 8, and progressively melts them, the upper skin of the advancing metal being contacted with and supported by their unmelted portions. These members 8, are embedded in the cope or walls for a suflicient distance,

usually the entire thickness, 'toenable them v to support the weight of the chilled skin, indicated generally at 10, thus ermitting the volume of the metal in the b0 y of thecasting to remain constant during cooling, due to the replenishment of the shrinkage metal by other metal supplied through gate 4 It will, of course, be understood that gate 4, is suitably connected to a reservoir of inolten metal so disposed and arranged as to provide a sufiicient head for replacement metal to maintain the body of the casting at its maximum volume during cooling, and prevent the shrinkage of the surfaces.

The combination of the surface support for the skin of the casting by the supporting members 8, and the maintenance of maximum casting volume by roviding a suficient excess of metal to ta e care of shrinkage, gives highly novel and satisfactory results. Constant use of the process daily for substantially a year shows no trouble due to the necessity of filling shrink holes and the like, as has been requiredheretofor.

\Vhile the support members have been shown as inserted and anchored in the cope, it will be understood that additional such members may be disposed in the walls of the drag, without departing from the spirit and scope of the invention. Such procedure will be particularly suited for use in the making of massive-castings, such as are used in safes, vault walls, and other massive constructions. v

Referring now to Fig. 2, there is shown a conventional mold set up, comprising a cope 12, .and drag 13, with mold sand 14 which.

has been rammed in place to form a mold suitable for casting. The mold is gated at 15 in the usual manner, and in addition, rods 16, of any suitable material and shape, are inserted through the molding sand into the molding space 17, in the manner previously described. The fundamental features involved here are exactly the same as those previously described, and no further discussion is necessary.

As illustrating the difliculties overcome by the practice of the present invention, there has been shown in Fig. 3 a diagrammatical example of a solid ingot which has been cast according to ordinary foundry practice. It will be noted that the body of the casting 17, has shrunken corners 18, and a very much shrunken face 19. As has already beenrintimated, .in order to prepare such castings for use, it has been necessary to chip out the shrunken face of the casting and add suflicient new nietal 20, to replace that lost by shrinkage and the subsequent chipping operations.

. It is also to benoted that, in order to secure true plane surfaces on the several faces of the ingot itself, it is necessary to machine them, a condition which is avoided by the .ppingiples of my invention wherein the several faces are held in' absolute contact with the surfaces of the mold by reason of the retaining rods and the weight of metal in the risers and gates of the molds.

The advantageous features of the present invention may be applied to small castings of any size and shape without departing from the fundamental principles herein set forth. In such instances the size of the supporting members may be varied to suit, and the pouring gate positioned in the cope, in the ordinary manner.

As intimated above, the present invention is adapted for use with a wide variety of metals, and while the preferred embodiment herein disclosed refers more particularly to copper and its alloys, the members 8 preferably being of trolley wire size, or the like, the use of any and all metals is comprehended. The members 8 may be made of any suitable metal, usually the same as that of the metal used for casting.

lt will now be seen that there has been provided an improved process and means for preventing shrinkage in metal castings, which are adapted for use with all kinds of metals, and more particularly for use with massive castings of the type described.

What is claimedis:

1. The improvement in the art of casting metals which includes supporting a semimolten body of metal from the walls of a mold.

2. The improvement in the art of casting metals which includes supporting a semimolten body of me al from the walls of a mold, whereby to prevent shrinkage of the metal on cooling.

3. The improvement in the art of casting metals which includes supporting a semimolten body of metal from the walls of a mold, and maintaining a pressure on the body of the metal sufficient to compensate for normal shrinkage losses.

4. Theimprovement in the art of castingmetals which includes supporting a semimolten body of metal from the walls of a mold, and maintaining a suflicient head of metal on the said molten body to compensate for shrinkage on cooling.

5. The im rovement in the art of casting metals whic includes supporting a semimolten body of metal from the cope of a mold.

6. The improvement in the art of casting metals which includes supporting a, semimolten body of metal from the cope of a mold, whereby to prevent-shrinkage of the metal on cooling.

7 The im rovement in the art of casting metals whic includes supporting a semimolten body of metal from the co e of a mold, and maintaining a pressure on t e body of the metal suflicient to compensate for normal shrinkage losses.

8. The im rovement in the art of casting metals whic includes supporting a semiin the walls of a mold and in the cope of a mold and molten body of metal from the co e of a mold and maintainin a suflicient ead of met on the said mo ten body whereby to compensate for shrinkage on cooling.

9. A support for cast metal masses, including a pluralit of metal members embedded j in the walls 0 a mold and preciable distance therein.

10. A support for cast metal masses including a urality of metal rods embedded in the we of a mold and preeiable distance therein.

11. A support for cast metal masses, ineludin a plurality of metal members embeddefin t e cope of a mold and projecting an appreciable distance into the mold chamr. 12. A support for cast metal masses including a plurality of metal rods embedded projecting an appreciable distance into the mold chamber.

13. A su port for copper castings, includa plum ity of copper membersemhedded projecting an appreciable distance into the mold chamber.

14. A support for copper castin including a plurality of copper rods em the Walls of a mold and projecting an appreciable distance into the mold chamber.

15. In a metal casting mold of the type described, in combination, a mold having top, bottom and side walls, suitable gates for the projecting an approjecting an apadmission of molten metal into the chamber I progressively formed by the said walls, and means embedded in the walls and projecting into the chamber, said means bein adapted to su port the skin of the mofien mass and be melted to an extent by the advancin metal.

16. l n a metal casting mold scribed, in combination, a mold having a co e and drag to ether with suitable gates for t e admission 0 molten metal to the mold, means embedded in the cope and projectin into the mold chamber, said means being a apted to support the upper skin of the molten mass and be progressively melted to an extent by the advancing metal, and means adapted to replenish the diminution of the metal of the mold normally caused by shrinkage on cool- This specification Feb, 1929.

of the type designed this 11 day of i=1? NRY L. COLES.

edded in v

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