US967830A - Production of castings. - Google Patents

Description

W. S. POTTER., PRODUGTION. OP CASTINGS.

APPLIOATION FILED 13110.17, 1,909.

Patented Aug. 16, 1910.

2 SHEETS-SHEET 1.

n INVENTOVR 4f' ATTORNEYS,

S. POTTER. PRODUCTION 0F CASTINGS.

YPLICATION FILED DEG. 17,` 1909. Patented Aug. 1.6, 1916.

- I I INVETOR Vif/4.,

ATTORNEYS heating operation.

\ i f i wie i i" rite El l il llllli l3nt itc illicit Specimen To all whom t may conifere:

Be it known that l, fini-Isin Si Porrnn., e citizen of the United States, residing; in the borough of Manhattan, city, county, anal State of New York, lieve invented certain new zindusefnl improvements in tlie 'Production of Castings; :intl ll lo hereby cle clarefthe following to he e full, oler, end exact description of tlie invention, sucli will enable others elrilletl in the nrt to which it appertiiins to ineke enel use the sinne. My invention relates to the production of ingots, blanks :intl irregular shapes ci metal. by e costing operation of suoli e character that when the costing ie reinovetl from the niolil in which it is formed it will poseess the physical characteristics 'suitable for per initting it 'to loe rolled, v'iorgcih hammered, reseeil or otherwise formeel to the desired finished shape Without the neeessityot si relu realizing this purpose, the method of cuetingeznployetl is or" suoli e character ns to substantially nvoitl irregularities of physical structure throughout the ingot, blank or irregular shape, espei cially in the outer portions thereof where they are otherwise liable to develop, enti which are prejudicial to the subsequent forming or shaping operations, unil also to Substantially prevent segregation throughout the ingot, blank or irregular- Shape, thereby prceerv" u; corresiioinling homogeneity of coni )osition :and distribution o 'the eonetituent el product. i

in the practice of iny invention, the casi? ing nielnl is poured into the inoltl at a teinperature but slightly above the freezingor setting point of the metal, in-ortler that the freezing or setting ofthe metal may lelie place rapidly. liloreover, the inetul is poured into the inolil, it coince in contact with mold surfaces of such n character es to exercise e chilling effect u )on the exterior of the casting. The rapid iieezing or setting of the metal, due to the relatively low temperature et which it enters the mold and due to the action of the chills is the iteuture upon which lrely to prevent segregation throughout. the casting, es, for instance. when the metal poured is steel containing phosphorus and carbon, to avoid the segregation for those elements and to maintain them in 'the casting,f in substantially the distribution which einents of the metal in the cast tire umili.v

lin realizing;1 the advantage tine to the substantial 'prevention ol segregation inthe c sting, there is developed, by the action of the chills, e. tendency to the formation, in tlie exterior `,iortio 1s of the casting intl in. proximity to its` outer skin, ol columnar or dendritic structures, which tendency, not countei'ncteil, would result. in fi, enst product unsu nele, without relieztting, for subsequent sliepingantl :toi-ming,

lt is, tnerefore, it mein cheraieterietic fee ture of my vinvent-ion to counteract the forznzilion of these columnar or dendritic structures and to eliminate any which nitty have been temporarily formeel, by permitting the casting to reninin in the inolil until the teniperatures have been redistributed throughout its mess that the conditions lTor the formation of such columnar or dendritic structures, or for their persistence in the casting, ere removed. To this enti, the high temperature prevailing in the interior of the casting, otter the metal luie trozen or set grailuolly transmitted lo the chilled. portions" 'to en extent suilicient Ator the purpose intended..

practice, 'the redistribution ol temperatures for the purpose intenclccl tney, in4

some instances, reise the temperature ot the exterior portions or' costing to even e higher degree than is absolutely reoniireti` for he elimination, of columns or ilenolritee, out this will usually be *found of advantage 'lor the reason that frequently the exigencies ot' the null require that the castings be helol temporarily in reserve before they een lee subjecteil to the shaping or forming oper ations and the entre, heat of 'the castings een, therefore, he mede available to keep them :it the forming and shaping tempera,u ture during brief periods oit delay. lf per ticuler circumstances involve such delay es ,would result in n drop in the temperature of the casting below the temperature neces sary for the forming or Shaping operation contemplated, they may bekent in Storage or reserve in n soaking; pit or the like so that they may not materially lose their casting lient. lt will also be understood that if, et the tenineretnre of' issuance from tliexnoltl, the castings ere too liot, for the forming or shaping operation intenclerl, they tney loe siey ' some instances,

avoid the presence cooled or permitted to cool until they shall lave reachedv the desired shaping or forming eat.

In order that the conditionsfor the presence of the columnar or dendritic structures s It will be noted, therefore, that the under;l

lying features of my invention embodj,7 (l) the avoidance of se egation in the casting, by the expedient o. ouring the metal at a temperature but sliglitl'y above its freezing point and by causing it to set 4 rapidly through the intermediacy of chills, and (2) the avoidance of columns or dendrites, by leaving the casting in high temperature prevailingin its interior shall have appropriately acted upon the outer zone in which' the columns or dendrites would otherwise tend to develop, and until the chills themselves have been raised to the temperature necessary to permit this action and also by the high temperature of the chills, arresting or avoiding any further formation of irregular structures in the outer portions ot the casting; with the final result that the v-rtasting, When removed from the mold, will have its temperatures so redistributed that the casting may be rolled,

forged, hammered, pressed, or otherwise shaped, as desired, and without the necessity of any reheating operation whatsoever.

In the redistribution of temperatures com te'mplated by my the appearance, 4in the cast product, of columns or dendrites, a suli'icient rise of temperature in the exterior portions ot the casting is attained by maintaining such a ratio between the mass ot the chills and the mass of the casting that the chills thein selves Will be brought to a temperature somewhat above that which is necessary for the avoidance of the columns or dendrites.

In fact, as hereinbefore indicated, the re-l the temperatures may, iny

distribution of bring the exterior of the casting to a temperature higher than is suitable for the immediate action of the forming or shaping apparatus, ln other Words, in attaining the temperature necessary 'to ot columns or dendrites in the product as it is'delivered from .the mold,the exterior portion of the `casting may reach a higher heat, Without disadin the redistri- L the mold, until theinvention in order to'avoid' senese vantage. )in all cases,'1 nevertheless, the hot casting is to be forming or sha ingoperatien intended, precaution must cool it if its temperature is too litigi.

in the case of steels, the temperature for the forming and sha ing operations 'will vary within considerab e limits; 'for instance, in the case of a manganese 12% of manganese and l% 'of carbon, the shaping or forming temperature suitable for the outer portions of the casting 'will usually lie somewhere between 110W C, and i299 t). W hen the desired redistribution et tempera! tures has taken place throughout the casting, and when, therefore, the' exterior portion has been brought to the condition contain plated for ltime avoidance et columns or dendrites, the. casting, in its liet state, removed from the mold and is either immedt ately or after suitable cooling, subjected to the forming or shaping operations intended, or, if it is necessary to hold the casting in reserve, it may be maintained in the heated condition for a shorter or longer period ot time, asl circumstances may require, in a suitable soaking pit or the like.

lt will be understood. that the conditions for successful. rolling, forging, pressing or the like, do not require a homogeneous or uniform distribution of the heat throughout the ingot. 0n the contrary, the interior porltions of the ingotfwlien removed from the mold, will usually be at temperatures only so far removed 'rom the melting point of the metal as to provide the necessary cohesion to resist crushing during the sha ping' or forming miei-ation,` While the exterior portions will be at varyingly lower tempera tures than the interior. The main. considerations are the lsubstantial avoidan segregation and the practical absence-,lof col umns and dendrites; the absorption of a portion of the interior heat oi the casting by the chilled outer portions, and' the like ab sorption of portion about all oi" the redistribution heat that is required.

lt will be understood that :while my invention is particulars' applicable to the malt inp; ot castings 'from steels having high percentages `of carbon, manganese, tungsten, nickel or the like, itis ot general application to the making of castings from other metals, such as aluminum and its alloys, alloys ot copper, etc., which are subiect to segregation and to the formation Aof irregular ieebly bonded structures of such a character as to require thc casting to be reheated before sub; sequent working. ln this connection, it may be appropriate to point out that Where reheating is required to adapt the casting to a subsequent formin l operation,-'the reheating is almost inver-ia ly accompanied by the steel having say subjected to the Bti llO

oil such internal heat bv the chills themselves suc'rnff to bring 30 the metal employed, thecolin'nnar or dendritic structures here prectieuliy diseppeered by the time the (resting is removed from the mold. Furthermore, there is an entire absence', in. the castings produced in accordance with my invention, of the sepereting out from the metal of certain eebty4v cementing compounds which ere present in the coliunnnr -or dendritic structures end which occupy therein the issures or creeks referred to.

feebly consenting compounds, ordinuriiy separating out 1n the class of ingots requir ing rehesting, are reebsorbed findredistrib? uted in the metal before lthe casting is removed :from the mold.

I wish further to emphasize the fact that my invention is not confined to the produc tion of ordinary mill castings such es ingots and blanks generally, but is applicable Wit-h corresponding advantage to the cesting oi'whet l have hereinbelore designated as irregular shapes, as, for instance, such shapes es eer Wheels, beveled gears and the like, cast e.pproxinfietelxv in 'the shape of the nished article end which ere 'then to be worked under a hammer or ,press to the desired form in the shaping die and which may iinally be subjected to subsequent heet `treatment .for hardening, annealing, or the like, as may be found desirable.

it is characteristic oi my invention and especially to be considered from the conimercial standpoint, that notonlj,T is the casting as it is delivered from the mold adapted to be subjected to the subsequent forming` or shaping operation desired, and that it is substantially devoid of dendrites and has set without segregation ot' its phosphorus,

carbon or the like, and that reebsorption:

and redistribution or" the compounds which form or tend to forni in the dendritic structures, have occurred 'during the period of heat distribution, but also that the casting has been brought to this condition in n single heat, byv redistribution of its own teinpemtures, und in ii correspondingly 'short eriod oi time, which, in nniny cases, will oe :it most ont one fourth oliE the time neces` sary for the usual 'operations oi costing); und retreating. Accordiugly` e niill equipped with my invention will have :i correspondingly high capacity, inasmuch es the iinvisl'ied castings, ready for the forming or shaping operation, can be produced rapidly* ln feet, it is one of the cherrie-A terlstic merits oiD my invention that these in eniount suiiiciento insureu e eenstariit supply for e end drowning nient of ierge output.

t' iin order to iiius'trete the scope and pui?u ,pose .of my invention Eo specific typlce inm "tsnces of ineens for puttiin it into effect, il have shown, in the eccoz per fing drew ingsits zipplicetion 'ow'tiie production respectiveiy o; e vertical ingot end oi en ingot oit e. sieb-like fvzoniiguretion, .it 'will be understood, however, that the perticuler illustreeiasis che in are designed to merely es instances of ineinjv others, included Within the range i invention hes been hereinbeiiore .sind ss vviil up peeriurther on in the sglreciiicetion 'in the appended cieiins,

in fiile drawings, lignr.n i., ,esente e'. vertical sectioned View of molt` eoperetns accordance with niv invent-ion.. 2 ren resents s.V cross-sectional view hereof teken on s. plane indicated by the line 2 2 of Fig. l. Figs. 3 and i represent respectively of mold eppsiratus for costing e, horizontal or slahdiife ingot in accordance with inv invention. y

Referring to the drawings and particularly to Figs. l end 2 thereof, the mold.

und side walls o iikewise of metal, which `side wells support en upper section or ces ing c I'itted over thenfi end which is provided with e refractory lining; el, oi' dre brick or the like. The bottoni a and side Weils oiii .the mold are intended to ect, in the first instance, es chills, for the purpose of causingr the casting metal :is it is poured into the mold to or set rapidly, in such manner es 'to prevent segregation of the phosphorus, carbon, or like segregsble elements, the cese may be. To this end, the inass oi" the chill bottoni a and chill sides is appropriei-elyproportioned to the tenipcruture of' the casting nietel and the 'volume which. it occupies un the mold, and the casting metal is poured et e temperature but slightly above tlnit oit' its freezing or setting point, so that the iireening or setting; of the ingot will. proceed with the required promptnessulp to the point represented by will remain temporarily liquid so thnt any cm'itiesproduced ybelow by the setting operation may be fed and hlled trein the liquid heed thus provided. In order that the cest ing, es it coines 'ron'i the mold, shell, be devoid of any of the irreguler, dendriticv to, i establish edjecent to the outer surfaces of the metal chills, ns they may be ceiled, c., the metal sides end the inet-nl bottoni of the mold), e body oft aneteriei which is but a sioiv conducter of heet. ."tn s, for the suitehle for producing s vertical. ingct vertical sections at right an to euch other u columnar structures hereinbe'tore reerred proper consists of e bottoni piece o of metal loo the brick-lined casing; c, Where the metei 'metal bottom a l may employ a subjacent pad or illing e of dry sand or asbestos set in a r'ecess in the foundation plate or base A o.A the apparatus andv I may employ a like E lling f, of dry sand or asbestos, in the anfnular space between the side Walls of the mold and an outlying jacket y. The thickvness and heat absorbing capacity of the walls b and of the bottom .a of the mold are so established that only the proper amount Ofheat is abstracted during the -pouring of .themetal te cause the mass of casting to freeze orset promptly, leaving out of conv 4sideration the metal Within the brick lined 3,5 casing c which remains temporarily liquid f to supply piping cavities. Radiation from the ends of the annular space between thev mold proper and the jacket g may be minimized and accidental intrusion of liquid metal between'the inner and outer walls of the mold may be avoided by building up an annular mound z, of fire clay or the like labove said annular space. The dry sand iilling f rests upon a ledge 'i attached `to the 25 inner. lower edge of the jacket g, and the mold Walls Z) are provided with a band lc with which are adapted to Yengage suitable lifting lugs Z u on the inner surface of the y jacket and the Jacket is provided with bails By this arrangement it is feasible to i readily strip the mold from the cast ingot Without losing any material part of the sand envelop f. p The chill walls b of the mold can be observed through sight tube openings provided for the purpose, at various places, or their temmrature can be otherwise determined,

and when that temperature has risen to the degree required, the mold is to be stripped from the ingot, which may then be formed or shaped, as desired, either immediately, or after cooling' somewhat, as may be most expedicnt, or after being held 'in reserve in a soaking pit. l In Figs. 3 and fl, which illustrate the productionof a iiat or horizontal casting in accordance with my invention, the chill surface of metal m is contained isthe main body portion n of the mold, which is pro- 50 vided with a cope r having a pouring gate 8, throu h which the ourin'g metal enters the mol and the latter is reheated by transfor the casting. -As before, the pouring metal is preferably cast at a teun the-@old cavity and underlying the chill of the casting until it attains a heat suiiicient to eliminate the dendritic orvcolumnar structures adjacent to theouter skin of the casting; whereupon, as in the vertical casting or ingot, the horizontal or slablike ingot is ready for removal from the mold and is adapted to be subjected to the shaping or forming operation intended. It Will be further noted, as characteristic of the practice of the invention, that when the ingot or other casting is ready for removal from the mold, it will have a substantially continu ous 'grain-like structure throughout and will have a plastic interior and a strong, tough criterion,l It is also' a vfeature of the inven- 80- tion that it presents means for producing, without reheating, ingots or castings which are sound, inasmuch as by retaining the casting in the mold atsuch a temperature in its outer ortion that it can be shaped or form and by having the upper portion at a higher temperature, any piping cavities or the like which may develop as the metal sets can be filled in with liquid metal until thel upper portions themselves in which these cavities exist shall have become solid and continuous. To further this filling in operation, metal at a relatively high heat maybe at hand for filling in the to of the casting, Which metal may readily be Ibron ht to the desired temperature in an electric urnace, or other like furnace operating at high temperatures.

Having thus described my invention, what I claim is:

l. The method of "producing mold castings suitable, without reheating, to be subjected to shaping and forming operations, which consists in pouring the casting metal at a temperature but slightly above its freezing or setting point, chill-cooling the outer portions of the' casting so as to assist in causing the casting to set rapidly, and then restricting the flow of heat from the chills until the chilled zone has been brought t0 a temperature necessary to remove freezing structures by the outward flow of heat from the interior of the casting; substantially as described.

2. The method of producing mold castings suitable, Without reheating, to be subjected' to shaping and forming operations, which consists in pouring the"castin metal at a temperature slightly above its reezing or setting point, chi l-cooling the outer surfaces of the casting so as to assist in causing the casting to set rapidly, then, by transmission of heat from its interior, raising the temperature of the exterior chilled zone of I the casting so as to "remove objectionable 125 freezing structures and to bring the casting to a condition suitable for the shaping or forming operation intended, and s1mul taneously raising vthe temperature of the '85 iilasidfgof-the temperature of the interior chills until their inner surfaces are likewise 130 tion suitable for i the chills until 3 'moval from the mold shall substantially brought to the degreel mission o heat from its interior raising the ing casting, ing p ace in thel casting from the mold and subjectlng cshapingl or forming operation intended, i wh et e temperatur isstill suilici'ently hi 450 1 1 efr/,eso u adapting them for shaping or forming opf erations, which consistsin pouring the metal in a mold, chill-cooling the outer portions of the casting so 'as to assist in causing the castingto set rapidly, and reheatingthe cxterior chilled zone, While the casting is still in the mold, to a .temperature above that at which the dendrites and other objectionable freezing structures will. be eliminated; sub s tantially as described.. I

-7. The method of--producingl mold castings of manganesesteel. lin* t e condition adapting them for shaping or forming operations, which consists in pouring intoa of heat required for the reconstruction of tovexterior zone of the' casting; substant J 'as described.

3. In the production-.of mold castings, the method of bringingthe'c'asting to a condition suitable for ,shaping or forniing operations, whichconsists 1njchil1-cool1ng `the outer portions of the casting so as to cause the casting to set-rapidly, and restricting the flow of heat. from the chillsfunt-il the chilled zone .has -been brought to the temrature necessary to' remove vobjectionable zing structures bythe outward iiow of heat from the interior of the casting; 'sub'- stantially .as described. 4. 'Inthe production of mold castings, the method'of bringing the casting to a` condishaping or'forming operations, .which consists 1n chill-cooling the outer portions of the casting so asito cause, the castin to set rapidly, and. then by. trans per cent. of man anese and about 1.10 per cent. of carbon, c ill-cooling theouterl por tions of the casting so us to assist in causing the ca'stin to set rapidly, and reheating tlie exterior c illed zone, while the casting is still inthe mold, to a temperature above that at which the dendrites and other objectionable freezing structui'will be eliminated; substantially as described.

8. The 'method of producing mold castings of' manganese steel in a condition adapting them for shaping or forming operations, which consist 1n pouring the metal -in a mold, chill-cooling the outer surfaces of. the casting so as to assist in causing the 'casting to` set rapidly and so proportionin the heat absorbing' capacity o the wallsc the mold to the amount of heat to be abstracted,A from the casting, thatl the outward flow of heatftakinglplace' in thecastin from the interior to t e outer.`v oxtions. t ercof, beforeaits removal from t e. mold, `tially eliminate' hays formed, "and finally' removing the casting from the mold'a-nd subjectingrit to the j sha in or forming v operation intenflefh, whi e t e tem rature in lts outer portions is still suilicient y high necessaryv for sha mg or tially as descri In testimony iwhereof I ax my signature, in presence of two witnesses:

WINIELD s. roirrna.V

temperatureof theexterior chi ed `zone of 75 the casting until objectionable freezing structures are 'eliminated and the casting .is brought to a condition suitable for the-shap- V or forming operation intended', and simultaneously' restricting radiation from .their inner surfaces are brought to the temperaturedesired for the surface of the casting; substantially as described. 5.V In the production of mold castings and the subsequent shapin or forming thereof, the method of practica lyl avoiding dendritic structuresin t efinal products, which consists in so ro ortioning the heat absorbing capacity o t e walls' of'the mold to the amount of heat to' bejabtracted from the that the outward flow of heat tak.

from the interior to. the outer portions` thereofibefore its .re-

any dendrites which may' have forming; substan thev casting it to :the

eliminate formed, and finally removing e in its outer portions hto afford the desired Y. i

lWitnesses ductility; substantie ya's described. 6. The method of producing mold (-,ast- Jona' 0;-PENNIL, ings of manganeseste'el in t Pmmw.

e condition l LAURAB"b mold manganese steel contalnlng about-.12` i I shall substananydendritcs which may'go to afford the ductility 96'

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