US1239586A - Art of hardening castings. - Google Patents

Description

J. W. G EBHARD.

ART OF HARDENING CASTINGS.

APPLICATION FILED FEB. 12. 1915.

1,239,586. Patented Sept. 11, 1917,

2 SHEETSSHEET 1.

WITNESSES I V i vsm'on J. W. GEBHARD.

ART OF HARDENING CASTINGS.

Patented Sept. 11 1917.

- SHEETS-SHEET 2.

UNITED. STATES PATENT OFFICE.

OHN w. GEBI-IARD,

F VANDERGRIFT, PENNSYLVANIA, ASSIGNOE TO UNITED ENGI- NEERING & FOUNDRY COMPANY, OF PITTSBURGH. PENNSYLVANIA, A CORPORA- TION OE PENNSYLVANIA.

ART OF HARDENING CASTINGS.

To all whom. it may concern:

Be it known'that I, J OHN N. GEBHARD, a citizen of the. United States, residing at Van'dcrgrif-t, in the county of \Vestmorelaud (and State of Pennsylvania, have invented a new and usefutlmprovement inthe Art of Hardening Castings, of which the following is a full, clear, and exact description,

reference being had to the accompanying drawings, forming part of this specification, in which-.

Figure 1 is a longitudinal vertical section showing a mold arranged for carrying out my process.

Fig. 2 is a horizontal section on the irregular line IIII of Fig; 1.

Fig. is a view similar to Fig. 1 showing the casting in place after completion of the operation.

F i g. 4 is a sectional side elevation.

Fig. 5 is a cross section on the line V-V of Fig. 6.

Fig. 6 is a horizontal section, showing another casting in place, .made in accordance with my inventionyand F ig. 7 is a perspective View, partly broken away, showing a vault plate casting made in accordance with my invention.

My invention relates to the method of making castings, particularly steel castings having a hardened face orportion formed by a layeriof hardenedmaterial within the mold. The hardened material is oi? an exothermic character, the reaction started therein by the heat of the molten metal, giving of? heat and causing a high temperature;

Heretofore in such processes two diiiiculties have been encountered. First, the reaction liberates gases and the hardening layer must be thin in order to give the proper character of hardened. portion. Hence, the hardened portion is of relatively shallow depth. Seconrhinasmuch 'as the hardening material as it melts occupies less space or volume than it does before melting, 1t

shrinks and does not entirely cover the face to be hardened.

My invention overcomes these difficulties and it consists broadly in feeding an additi'onal supply of the hardening material Specification of Letters Patent. 1

to the face or portion of the casting to be hardened after the melting of the hardeningmaterial begins.

In carrying out my invention, I provide an additional supply of the hardening ma terial in such relation to the face or portion to be hardened that, as the fusing of the hardening material progressively proceeds, this supply will be melted and supplied'to the casting. Ia'lso arrange this additional amount in such a relation that as the hardening material melts and gives out heat, thus combining with the desired portion of the casting, space will be provided to allow the slag and gases to arise, thus giving a better character to the hardening portion, relieving it from sponginess, pipes, slag, etc.

I will now describe my. process, referring .to Figs. 1 to 3 of the drawings, In these figures, 2 represents a sand-mold for easting a steel'stamp-head, 3 the mold shapingcavity, 4 a sink-head cavity rising there'- from, and 5 a pouring-gate. This gate comaround the core-like portion 10 and the neck portion 11 of the hardening compound, and then rises over the portion 9 Within the mold-torming cavity.

Then the mold is filled, and when the steel begins to thicken, the reaction will begin in the hardening compound. Thisreaction sets free a large amount of heat and will extend progressively through the com- Patented Sept. 11, 1917. Application filed February 12, 1915. Serial No. 7,694.

pound which melts and combines with the lower part of the steel casting, remelting this portion oi the castingl As this action pro ceeds through the compound it will extend through the neck into the portion 10, and as these portions melt they will keep molten the interior of the sink-head and its neck connecting with the lower part of the mold,

thus feeding an additional supply of the hardening compound to the desired surface and at the same time allowing the products of the reaction, such as gas and slag, to rise through the center part of the additional sink-head.

When the casting is finally chilled and solid, it will be of the general form shown in Fig. 3. The slag shown at 12 resulting from the reaction of the hardening com pound will lie within the sink'head below its 'top and the hardened portion of the stamp-head will connect with the hardened portion of the sink-head which remained molten after the steel was solidified.

When the casting is removed from the corresponding to the depth of the hardening material supplied, the heat of reaction, etc.

The hardening composition employed is of exothermic nature, its reaction giving out a large amount of heat, andI may use difl'en ent kinds of mixtures. For example, Ihave used a combination of finely ground manganese, chrome, SiO aluminum-and linseed oil; or a mixture of the same with nickel.

One mixture which I have employed with success is manganese 4.52 parts by volume,

r .chromium parts by volume, SiO 1 part,

aluminum .1 part, nickel 6 parts and oil 3.5 parts.

' Such compositions have an exothermic reaction which starts after the steel has been poured in the mold and usually about the head cavities. I

When the molten steel is bottom cast into this mold it will fill themold and rise within the sink-heads, and as it is beginning to set, the hardening compound-will begin its reaction at the bottom of the layer, this reaction proceeding upwardly, thus melting the compound and the adjacent part of the casting. During the time of reaction the slag and gases will rise, and as the reaction enters the sink-head cavities, the portions of compound therein will feed down into the cavity proper vto supply the required amount of material for hardening the com- .plete face of the castingproper. When the entire casting has finally set, the sink-head portions will contain the slag from the reaction in the cavities formerly occupied by the compound. This compound will shrink and settle more than the steel, thus leaving the cavities shown.

In Fig. 7 I show a cast steel vault plate having the side softer portions ll and the intermediate harder portion 15. In this case the hardening material is prcfeably spread over both sides of a support such as wire netting, expanded metal or rods. This support is provided with extensions which project up within the sink-head portions of the mold cavity so that the hardening material spread thereon will extend up within these cavities. The action will be the same in this case as in the other cases. the portions 3 of the compound within the sink-head cav mold, the sink-heads are of course cut oil, thus giving a stamp-head with a face hardened over its entire surface and to a depthities sinking down during the reaction and the slag and gases rising to the top within the sink-heads.

An additional supply of the hardening reactive compound may be placed in the sinkhead cavities if desired.

The hardening compound or alloy is proportioned so that it will not be taken up by the steel as it is poured, but will remain in steel at the side or around the compound, the

impurities rising to the top. The alloy portion of the tre ed section will.remain'liquid for some time after the steel has become solid.

The hardening compound is compressed sufiicicntly to hold its shape, but is more or less spongy and contains air. This air will supply sufficient oxygen for the initial reaction; and through the remainder of the fusing action, air will be drawn in for combustion from and through the forming mold, spch as sand.

The hardening compound is fusible. lhat is, it contains fusible material so that the compound as a whole will melt and flow. It may, however, contain powdered material which has such a high melting point that it may not fuse, or at least not completely fuse,

but remain in solution in the fused pompound. By the word fused or fusihle in my' claims, I intend to cover the-"compound whcther it fuses in'whole or in part.

The advantages of my invention will be obvious to those skilled in the art; since any desired surface or portion of the casting may be hardened throughout its entire. exteht. as I have overcome the difliculty in. shrinking of the compound layer. Furthermore a better hardened material is afforded, since the impurities are released :ind allowed to pass more, the hardened alloy portion of the cast- 7 ing is cleaned from impurities which are allowed to pass up through this alloy portion while liquid.

Many variations may be made in the form and arrangement of the mold, the hardening compound and the arrangement and connections for feeding the compound into the mold cavity, without departing from my invention.

I claim:

l. The methodof making a casting having a hardened portion, consisting in casting the metal into a mold having hardening ma.- terial formed as a part thereof, and feeding an additional supply of the hardening material into the mold; substantially as described.

2. The method of making a casting having a hardened portion, consisting in casting the metal into a mold cavity containing hardening material capable of giving an exotherexothermic reactive mic reaction while fusing, and feeding additional fused hardening material to the portion of the casting to be hardened as the exothermic reaction proceeds substantially as described. 7

3. The method of making a casting having a hardened portion, consisting in providing a mold having extensions from the shaping cavity thereof, said mold containing a hardening exothermic reactive material within the mold and its extension, and casting the metal thereinto; substantially as described.

4. The method of making a casting having a hardened portion consisting in roviding the mold with a layer of exothermic reactive hardening material extending within and be yond the mold cavity proper, and causing said extension-portion of the compound to feed into the mold during the reactive period: substantially as descr'bed.

5. The method of making a casting having a hardened portion, consisting in forming a mold cavity with a sink-head extension. open to the atmosphere, providing the mold with hardening material extending into the sinkhead ing steel thereinto in contact w th the hardening material in the mold cavity; substantially as described.

6. The method of making a steel castinghaving a hardened portion, consisting in feeding.the steel into a mold and bringing it in contact with a. hardening material having an exothermic reaction. material in liquid form to the portion of the casting to be hardened substantially as described.

portion, and cast- ,p

and feeding said 7. The method of making a steel casting having a hardened portion, consisting in casting steel into a mold, bringing the steel into contact with a hardening compound,- having a suflicient exothermic reaction to remelt the steel portion to be hardened and the compound and thereby form a hardened al- 10y, and feeding the compound to the part to be hardened as the steel sets; substantially as described.

8. A mold having its. molding cavity provided With an extension, said mold having a layer of exothermic reactive hardening compound extendingwithin a part of the moldcavity and its extension, said compound being adapted to fuse under the action of the molten metal poured into the mold; substantial ly' as described.

9. A mold having a sink-head cavity connecting with the molding cavity, the molding cavity and sink-head cavity being pro vided with hardening compound adapted to be contacted with and fused by the molten metal; substantially as described.

10. A mold having a molding cavity pro-' vided with an extension, and a hardening compound located within the mold and its extension, and adapted to fuse progressively when contacted with by the molten metal fed into the mold and flow to the portion of the ive a sufficient exothermic reaction to re-.

analloy with the steel throughout said portion; substantially as described.

' 12. A'mold having its molding cavity provided avith an extension, and a.v layer of hardening compound. within the mold cavity and extending into the extension, the com pound being adapted to start an exothermic reaction about the time when the steel begins to thicken or set, and feed sufficient of the hardening compound to alloy with the entire portion of the face to be hardened, substantially as described.

13. A mold having its molding cavity rovided with a cavity extension, and a shaped layer of fusible hardening compound contained within the mold cavityand extending within the extension, the hardening compound being arranged to fuse progressively after it is contacted with by'the'molten metal poured into thd' mold and to feed as a fused compound to the'surface to be hardened. said compound giving an'exothermic reaction during its progressive fusing, substantially as described.

14. The method of making a casting having a hardened portion, consisting infeedv Tn testimony whereof, T have hereunto set mg the casting metal lnto a mold having my hand.

v I z 7 v a 1113a of haldemng maten 1l pleyloqsb Jon} W. (I L Li {Am}. upphed thewto and progressnely ieedlng fused hardemng materlal to the portlon de- \vltnessosz sued to be hardened to alloy thercw1th,, sub- W. C. LYON, stantlally as described. H. M. Comm);

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