US1166167A - Forming castings. - Google Patents

Description

- L.\G. woons.

FORIVIINGv CASTINGS.

APPLICATION FILED APR. I3, I9I`2.

Patented Dec. 28, 191.3.

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FDRMING CASTINGS.

` Specification of Letters Patent.

Patented nee. as, fait.

Application filed April 13, 1912. Serial No. 690,482.

To all whom t may concern:

Be it known that l, LEONARD Gr. WOODS, a citizen of the United States, and resident of Pittsburgh, in the .county of Allegheny and State of Pennsylvania, have invented a new and useful lfmprovement in Forming Castings; and ll do hereby declare the following to be a full, clear, and exact descri tion thereof. y invention relates to the forming o castings. lt is a well known fact that it is very desirable to form certain castings with the metal in di'erent portions .of the casting differing in physical character from that in another portion of the casting, for example, in armor plate, agricultural steel's and the like, it is desired to form one face extremely hardtosustain wear, while another portion is tough arid strong to sustain'the hard wearing surface. ln rolls, dies and other castings it is also extremely desirable to have a very hard working surface and have the body of the casting tough and strong to sustain the same. It has been found practicable to produce a very hard steel having great wearing power but it is usually so brittle that it.wi1l not sustain the heavy strains brought upon rolls and other similar details of machinery. Probably the best metal which has yet been used for such articles is what is known as chilling cast iron, where the iron when quickly cooled or chilled against ametal surface assumes a peculiar crystalline con` dition which gives a hard wearing surface, and the unchilled portion of the metal has considerable tensile strength; but even such rolls are liable to crack under -very heavy strains. By my invention l am enabled to employ these very hard metals 'such as steel or chilling castiron so as to obtain hard wearing surface and form the body portions Of the castings of relatively great toughness or tensile strength. l am also enabled to reverse the physical character of the metal in the castings as may be desired, for example, forming a tough eX- terior and a hard interior.

My invention proceeds upon the lopposite theory from that usually followed in attempting to produce ingots or castings formed of metal having varying physical characteristics, in that byalloying certain metals with the molten metal forming the castings l vary the chemical composition of the metal thereof instead of depending on differences of structure due to dierences in heat treatment. t i

ItV consist in producing such castings by varying the composition of the metal in the mold while in a molten state, such as by inserting into certainparts ofthe mold an alloying metal which will melt and alloy with certain parts of the molten metal after the other parts thereof have become solidied.

lt also consists in forming ingots, castings or the like bysupporting Within the mold cavity an alloying metal of a lower melting point than that of the metal to be cast, andlcasting` the molten metal around or in contact with the same, so that it unites `with a certain portion of the molten metal within the mold, the other portion of the molten metal being solidified, such as in Contact with the outer walls'o-f the mold, and remaining in its unalloyed state, and in this way changing the character of the metal of the casting itself by forming the alloy within the mold and during the casting of the article.

ln the accompanying drawings Figure l is a vertical section illustrating the casting of a roll within a sand mold in accordance with the invention; Fig. 2- is a like view illustrating the casting of a mold wherein a chill or metal mold is employed; and Fig. 3 is a sectional View illustrating the formation of a slab or plate, for example, an ingot or the like.

'llhe invention can most easily be illus- .trated in connection with the formation of steel rolls, though it is to be understood Vthat it is not limited to the use of steel or to the formation of any form of ingot or t casting, as the principle involved may be 'employed with any metal and in the formation of any article. Considering the invention, however, as applied to the formation of'a steel roll, such as illustrated in Fig. l, where the roll is formed in a sand mold,

the mold parts are formed in the usual way,

it being preferred in such type of mold that it shall be formed in three sections 1, 2, 3, the middle section 2 forming the body l of the roll, and the top and bottom sections forming the necks 5 thereof. The molten metal is fed to the roll through a runner 6 and a side runner 7. ln this case it is desirable to provide a very hard wearing surface and this can be obtained from a very hard steel, and to that end the cast steel kmelting point than the steel is formed high in carbon, and may berendered still harder by the use of-certain other alloyed with the steel will its toughness and strength.

'be used-in the form of thin bodies such as rods, wire, or metal strips 9, or even of the metal in small particles contained` in finclosing tubes-10 having a lower melting point than the steel. As illustrated in the drawing these thin bodies of metal are properly seated in the ends ofthe two end mold sectionsl and 3; This may be accomplished in any suitable way, for instance by seating the same in corepieces at the top of the mold section and carrying them down and port the thin bodies, wires, rods,

seating them in a like core piece in the bottom mold section, or, -for that matter supstrips 9 or tubes 10,l and so hold them in place. Any

suitable metal or alloy having a lower melt- Y rods or thin bodies,

. outer ing point than the molten metal may be employed for this purpose, it being preferred that the metal will not melt too rapidly but will gradually melt oil' and alloy with the molten metal in the mid-portion of the mold as the metal rises within vthe mold cavity. Indeed, in 'forming some steel castings where the steel can beraised to a heat higher than the melting point of the alloying metal, an alloying metal of as high a melting point as that of 'steel may be employed, the only requirement being that the outer portion of the steel casting shall solidity-before the alloying metal becomes molten to alloy with the other part of the molten metal poured. For example, thin bodies of copper or alloys of copper having a'suitable melting point,'may be employed, or nickel or an alloy of copper and nickel in suitable proportions having a suiicilently low melt-"1E ing point for the purpose. For castings of suiicient size the alloying metal 4may be con-- tained within a suitable holder, for example, `within the tubes 10the holder itself being formed of-met'al which will melt so as to feed the alloying metal to the steel body. After the mold has been formed in the manner above described and the thin bodies 'of alloying metal beenwproperly supported therein, .the molten steel is poured through the runner and rises around the inclosing the same, the steel, however, in the example shown, filling the main body portion of the mold and its portion contacting With the cold outer face of the mold being suiiiciently chilled or kcongealed as to cause its solidification Without its being acted upon by the alloying metal, while the interior of the castings rethe body ,alloying of the same are laid upon the drag ing the lower portion 20 mains suiiciently molten to be acted upon by the alloying metal as it is melted and dissolved within the mass of the molten steel. In this way, by proper manipulation as is learned by experience,the casting can be formed with the outer 'face or periphery of a very hard ysteel and the inner body of a tough strong steel resultant from the alloying therewith of the thin bodies of metal supported ,Within the body of the mold.

yIn Fig. 2 I have illustrated the mold as vused in the practice of the invention with an iron chill portion forming the' mold for of the roll. This figure vhas the same reference Vnumerals as Fig. l except vthat the metal chill is marked 12, it heilig formed ofV suitable iron casting. The mold is made up inthe same Way andthe molten 'metal may be either. the hard steel or a chilling cast iron. In either case it is practicab/le to toughen and strengthen the interlor portion of the casting while the chill 12 provides for the immediate setting or solidification of the outer portion or wall of the. casting and prevents possibility of the during the formation of the casting.

Fig. 3 is intended t0 illustrate other uses of the invention, for example, the formation of an ingot block or the'like.y In said figure the mold has a metal bottom .plate 15 for chilling .or congealing the metal poured within the mold and an inclosing drag flask 16, and a top or cope 17, and the thin bodies of alloying metal, bars, rodsor the like, 18, mold and the cope is then placed upon the same to hold them in place. The metal is poured through the runner 19 and as it strikesv the bottom chilling face it is quickly chilled and reduced to a temperature below that at which it -Will be alloyed, While when the molten metal rises and surrounds the thin bodies or rods 18 oi the alloying metal it will melt and unite with the molten metal poured, so producing a castoit which is of hard metal according to the composition of the steel or other metal employed while the upper portion ofthe molten steel melts the bodies or rods and causes kan alloying of the molten steel therewith and so increases the strength and toughness thereof and forces a tough backing to the hard metal of the casting.

It is believed that the above are sufficient illustrations of the general principles of the invention involved, which includes the changing of the physical character of the metal in certain parts y of the casting by alloying'with that portion of the metalnnd metal or alloy of a lower melting point the action of which is limited to that part of the casting, -itbeingfmy intention to cover this principle broadly with any metals to which it is applicable. In the practice .of

moeder the method it is also evident that by select ing or forming an alloying metal or com pound thereof melting at a known heat l am enabled to control the depth of the metal in its original molten state which is set or chilled before the alloying action commencesv sisting in supporting within the mold an a lloying metal and pouring the molten metal in direct Contact therewith so as to entirely surround and alloysaid alloying metal with the molten metal.

2. The method of changing thecharacter of the molten metal forming a casting, consisting in supporting within the mold an alloying metal having a lower melting point than that of the molten metal and pouring the molten metal in direct contact therewith to completely allo7 said alloying metal with said molten metal.

3. The method ot changing the character i of the molten metal torming a casting, consisting in supporting within the mold a thin bodyor bodies ot' alloying metal and pouring the molten metal entirely around and in contact therewith.

4. The method of changing the character ot' the molten metal forming a casting, consisting in supporting within the mold a thin strip or strips of an alloying metal having a lower melting point than that of the metal to be cast and pouring the molten metal around and in Contact therewith.

rlhe method ot increasing the strength of the interior or' a casting, consisting in supporting within the mold cavity an alloying metal which when alloyed with the molten metal of a casting increases its strength, and casting the molten met-al around and in direct Contact therewith and thereby melting the strengthening metal and causingl it to alloy with the molten metal.

In testimony whereof, I, the said LEONARD Gr. VVoovs, have hereunto set my hand.

LEONARD G. 1WUODS. `/Vitnesses A. STUCKI, ROBERT C. Tor'rEN.

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