US1679582A - Method of and apparatus for casting metal - Google Patents

Description

Aug. 7, 1928. 1,679,582

J. M NELSON METHOD 0F AND APPARATUS FOR CASTING METAL Filed Nov. 19, 1926 ZShQSGS-Sheet 1 JY (fameSM/Ye/am.

Aug. 7, 192s. 1,s79`;5s2

J. M. NELSON METHOD OF AND APPARATUS FOR CASTING METAL Filed Nov. 19. 1926 2 Sheets-Sheet 2 Hrramvfrs Ainalterata Aug. 7, v1928.

y 1,619,582; UNITED STATES PATENToI-Flcl-z.,

JAMES M. NELSON, or YoUNGsroWN, oHIo. n

METHOD. OF AND APPARATUS FOR CASTIN G METAL.

Application filed November l, 1926. Serial No. 149,289.

operation the undesirable gases which are' formed therein; to prevent the drawing of air into the metal While it is being teemed and to prevent the formation of slag from the reaction between the oxygen in the air when in contactwith the molten metal and the metalloids in the latter.

An additional ob'ect of the invention is to Vprovide a novel orm of pouring nozzle plate adapted for operative association with the pouring ladle of such character that a tight seal may readily be effected between theJ nozzle plate and the hood or other receptacle into which the metal is being l poured, therebynenabling a vacuum to be W readily maintalned in the hood or thel receptacle during the casting opera-tion as will hereafter more fully appear.

The invention further includes other objects and novel features of operation, design, construction and arrangement of parts and instrumentalities hereinafter more particularly mentioned or which will be apparent from the following description of one manner of performing my improved method and trated in the accompanying drawings.

Generally speaking, my improved method air from the interior of the receptacle priorto and during the pouring operation after the connection of the ladle therewith, and the distribution of the molten metal from the receptacle to a mold or molds arranged adjacent thereto in such manner that the metal of an apparatus suitable therefor as illus` in its traverse to each mold will drive before it the air and gases contained lin the passage by which the mold is connected with the receptacle and thereafter, as the teeming of the metal is continued, 'giadually fill the mold and form the complete ingot. Thus, asthe 'interior' of the receptacle -is devoid or substantially devoid of air at the commencement of the teeming operation and as no air Vcan thereafter enter the receptacle, the metal therein is not exposed to the effects of the oxygen in the air as when the pouring is done in the usual manner, while as the met-al in its traverse from the receptacle to the mold completely fills the passage to the vlatter and drives before it the air initially kcontained in it and. in the-mold, the only part of themetal which is exposed to the air atl all is that portion thereof which initially forms the, front or leading end of the'stream of metal in the passage and thereafter the upper end or surfaceof the ingot.

Itv will therefore be apparent that from the time the metal leaves the ladle until the mold .is filled only a very small portion thereof ofthe receptacle by the vacuum pump or v escape from the mold to the external atmos? phere with the result that thel ingots produced are dense and homogeneous in structure, devoid of blow-holes to a very large degree and have smooth and regular outer surfaces.

.It is to be understood that the present invention particularly lends itself to the simultaneous casting of a plurality of steel ingots although equally adapted for the casting of a single ingot at/'a time if preferred,

and to enable those skilled in the art t'o comprehend and practise the invention I shall therefore describe one manner of performing the method `so as to produce a plurality of ingots simultaneously as well as as one form of apparatus suitable therefor, reference being had to the said drawings in which Fig. 1 is al central vertical section through the main portion of one form of the'apparatus; Fig. 2a fragmentary view partially in elevation and partially in central section showing the apparatus in association with the ingot molds as arranged for casting a plurality of ingots, and Fig. 3 a-fragmentary horizontal section on line 3-3 of Fig. 2.' In Fig. 4 I have shown ilo . scribed. The inner wall of the hood at its `under such conditions being iilled from the bottom instead .of from the top whereby, during the teeming of the metal fromthe ladle, the metall is cased .to gradually rise in the molds until the latter are filled `to the desired point. 'v

As shown in the drawingsfthe apparatus comprises a hood 1 which may consist of a hollow7 cylindrical tubular element conveniently -of metal and open at both ends, this hood being adapted under operative conditions to rest in an upright position upon a stool 2 hereinafter more particularly deupper end maybe outwardly iared or bev- 'eled as at 3 to receive the'lower end of a substantially semi-spherical hollow cover 4 operative to close the upper end of the hood. Preferably the lower outer corner of the cover may be rounded off and after it is seated in .position on the hood an asbestos or other suitable packing or gasket 5 may be disposed between the cover and the hood so as to hermetically seal the joint between them. The hood\is provided at its center with an opening 6 which may be chamfered.

out at its upper end to form a seat for a ring 7 of asbestos or other suitable packingmaterial, the innerface of which is preferably arranged to conform to the surface of the pouring nozzle plate 9. This nozzle plate comprises a central portion or boss '10 of inverted, substantially semi-spherical contour and, preferably, a supporting flange 11 integral therewith to enable. 'the convenient attachment of the nozzle plate to the under face or bottom of the ladlel 12 b. means of bolts 13 extending through the ange. The ladle may be of any preferred contruction, that shown comprlsing an outer metallic wall 14 and a lining 15 of refractory material through both of which is extended the usual nozzle N, also of refractory material, and surrounded b a packing of clay; the nozzle is provide with an outlet opening` 16 in the. usual manner which is continued as at 16 centrally through the nozzle plate into a depression in the upper face of which the -lower end of the nozzle may be extended. This outlet may be'provided with a movable stopper or plug 17 of any suitable t peA for controlling the flow of metal therethrough.

As it is requisite for the performance of my process of casting that ingress of air'into the hood l beprevented from the time the lladle isbrought to pouring position until the casting operation 1s` completed and as it is .extremely diilicult in practice to exactly control the movement and position of a large pouring ladle filled with molten metal, I deem my improved nozzle plate having a semi-spherical exterior surface as aforesaid as of greatimportance since, when a nozzle plate of that.. character is'employed, it is only necessary to bring the plate to seated position in the aperture in the hood cover to insure an air-tight connection between the parts even though the ladle be tilted considerably from a vtrue horizontal position; moreover, this air-'tight connection will be maintained throughout theI casting operation eventhough the ladlel after being seated on the hood should tilt or shift slightly from its initial position. i

The hood or receptacle 1 serves to eny close a central runner 20 which may consist of a hollow cylindrical vertically extending main portion 21 desirably of smaller diameter than the hood and a flaring upper portion 22 'forming a funnel-shaped element for receiving the molten metal as it. issues from the nozzle and directing it into the runner. The portions 21 and 22 if formed-separately may be connected as shown through the medium of cooperating anges secured ltogether by bolts 23. In order to afford adequate support to the runner, its lower extremity may be. suitably increased in'diameter as atl 21 and' also provided with a marginal base flange 24, While for preventing the molten metal from contacting with the metal of the runner as it passes therethrough the latter may be'provided throughout lits extent with an inner lining 25 of suitable refractory material. lVhe'n the parts are operatively assembledthe runner is preferably positioned substantially coaxially with the hood and in alignment with the opening in its cover sol that the metal issuing from the nozzle will-enter the runner centrally with consequent avoidance of splashing.

As hitherto stated, the hood is operatively supported on the stool or base2, which also serves as .a support for the molds 1M, M which may be arranged about the hood and preferably as closely adjacent thereto as may be convenient. fThese molds may be of any suitable form for producing the ingots or other castings desired, and IA have therefore merely illustrated them in a conventional manner, it being, however, understood that Whatever be the specific form of the molds they are preferably open, either Wholly or in part, at their upper and lower ends and adapted to receive the molten metal at the latter. It is further to b e understood that while four molds arranged symmetrically about the hood are indicated in the drawings, any desired number of molds j may be ntilizel and arranged adjacent the hood in any desired Way. i

The stool, which may be formed. of cast-- iron or other suitable material, may be provided with a plurality of channels divergf ing outwardly from a common vcenter aligned f with the central runner. These channels, which are preferably open at the top,y respectively extend' to the several molds and may be lined with hollow brick or other suitable refractory material while at the point of juncture of the channels may be positioned a large brick having a central opening aligned with the vcentralv runner and forming a vsump 26 and horizontally disposed holes respectively communicating Awith the passages 27 in the bricks which Yexternal atmosphere.

In accordance with the practice of my improved process of casting it is requisite to exhaust all or substantially allof the air from the interior of the hood after the pouring ladle has vbeen `brought into posi# tion thereover and the nozzle plate seated in the hood cover but lbefore the' teeming of the metal is. commenced. Means must therefore be provided for temporarily `cut ting ofi' the sump and passagesA from'the interior of the hood since in thev absence of such means it.would be impossible to exhaustthe airfrom the hood, for as fastr as the air was removed it would be replaced byother air drawn in through the passages yand the sump. Therefore for the purpose of closing the lower end of the hood against. the entrance of air while a vacuum orjsub.

stantial vacuumV is being created`v therein prior to theteemin'g of the metal, I preferably dispose a relatively thin .plate 30 of metalI or other suitable fusible material between the lower end of the ,hood and "the surface of the stool, this plate being of sufficient size to extend entirely over the end of the hood and preferably project slightly beyond the same, and for insuring a tight vseal between the end of the hood, the plate and the surface of the stool, I may dispose annular l askets 3l and 32 of asbestos or other suit'a lematerial above and below the plate, the width of these gaskets being preferably such that neither of them will overlie 4the open end of the sump although extending from the exterior of the hood substantially to the perimeter of the sump,

Suitable means are'provided for exhausting the air from the interior ofthe receptacle, saidV means conveniently comprising an air pump ofsuitable form (not shown) connected withthe yinterior vof thejho'od'by a pipe 34 threaded into a suitable aperture disposedatl any convenient point in the hood wall.

In performing my improved method of 'casting with an apparatus substantially of the character of that hitherto described, v the hood, fusible plate 30, gaskets 31 and 32, if employed, and central runner are first assembled on the stool with the runner in alignment with the sump 26, the hood cover vthen placed imposition and the gasket 5 inserted so asto form a tight seal between the cover' and the hood. The molds are alsoand lowered until the nozzle plate 9 is seatedf in the aperture in the hood cover and Y against the packing ring 7 ifthe latter be employed. The interior of the hood being ,thus sealed against the admission of outside air, the vacuum pump `is operated until all or substantiall 1 alllof the air is exhausted from the interlor of the hood and the stopally filled untilthe desired level isattained in them a'fter which. the stopper is operated to cut off the further Iflow of metal from the ladle, thus completing the casting operation.

"It will thus be apparent that at the initiation of thel teeming operation avacu or substantial vacuum exists within thehood and this condition is'maintained throughout the teeming operation. As a sufficient body fusing of the central part-of the fusible plate 30, ingress of air to the interior'of the hood throughthe bottom ofthe runner is thereafter prevented, -while as the moltenl metal flows outwardly fromthe sump to the several molds the airin the passages 27 and in the molds is driven before the met-al and passes/out through the upper ends of the l molds as the latter aregradually filled-along i with a large proportion of the gases generated in the metal itself, n o part of which is thus exposed to the atmosphere while the metal is being te'emed save the relatively small portions thereof which initially form `the leading ends of the streams yof metal in the passagesy andjthereafter the upper ends of the ingots las they are formed in the of themolten metal is -resent in the runner to seal the lower end o v thesame before the` .lllll lll5 lll)

l molds. In consequence the main body .of

' into the central runner.

.from theladle to the runner which assists in the liberation of these gases, as well as because the metal passes through a zone of reduced pressure in a'rela-tively thin stream c the volume ofwhich is small compa-redwith its surface area. As these gases areso liberated they are continuously removed from the hood 'during the teeming yoperation by the vacuum pump so that the metal reaching the molds is to a large extent free there' of with the result that the finished ingot, save, perhaps, at itsupper extremity where the metal has necessarily come 4into con- .tact -with the'air in its traverse of the passages 17 and as it rises in the molds, is substantially devoid of blow-holes and presents a very smooth and even exterior surface,`

tlius materially reducing the amount of metal which must be cut ott from the ends lof the ingot and chipped or otherwise removed from its surfaces to prepare the ingot vfor further operations in conformity with `the usual practice.

In Fig. 4 I haveshown a slightly modified form of apparatus in which the central run-- ner is .integrally joined to the hood instead of being separate from the latter as in the form of apparatus hitherto described. While I have shown this connection between the runner and hood adjacent their lower Cil ends, it will be obvious that it may be effected with equal facility at any point below the funnel at the upper .end of the former, the `ipe 34 extending to thevacuum pump being, of course, inserted in the hood wall at ai point above the web 35- which forms the connecting element between the parts.

It will ofcourse be understood that prior to each cast a new lfusible plate must be supplied in order to seal the hood and enable a vacuum or substantial vacuum to be formed therein and furthermore, that while I prei Ifer to form thefhood `andcover separately,

as shown, under certain conditions it may be-found desirable to makeV these parts as a single unit or to otherwise modify vor vary the details of design, construction andarrangement of the apparatus or specific man- `ner of performing .the method to adapt the inventionl to the particular. conditions of operation under which it is tobe employed or for other reasons, and I therefore desire it to be understood that such` modifications and variations are contemplatedby me and may be made when and if desired without,

departing from'the spirit and scope of the invention as defined in the appended claims. I-Iaving thus described my invention, I claim and desire to protect by Letters Patentjof `the United States:

vl. In an apparatus for casting metal, a

hood, a fusibleelement closing the base vof the hood, an aperture in the Wall of -the hood above the element adaptedl for the reception ofthe nozzle plate of a casting ladle, and means for exhausting the air within the hood when said aperture is closed by said nozzle plate.

2. In an apparatus for casting metal, a hood, a fusible element closing the base of the hood,an aperture inthe wall of the hood above the element adapted for coopera-y tion with the nozzle plate of a casting ladle ing vthe air i'n the hood when said aperture is closed by the nozzle plate, supporting means for thehood, and means for conductinfr the molten metal from a point beneath said fusible element to a mold `disposed adjacent but outside of said hood.

3. In-an' apparatus for casting metal, a hood, a fusible element closing the base of the hood, an aperture in the Wall of the hood abovethe element ada ted for the reception of the nozzle plate o a casting ladle and cooperative therewith to form an air-tight sea'1,me'ans for exhausting the air in the hood when said aperture is closed by the n nozzle plate, supporting means for the hood,

and means or conducting the molten metal from a point beneath said fusible lelement t0 a mold disposed adjacent but outside .of

said hood, said means comprising a passage formed in said supporting means and' ter- .minatingat its outer end at the bottom of the mold.

4. In an apparatus for casting metal, a ho'od having an opening in .its upper portion adapted for the reception of the nozzle plate of a casting ladle, a fusible element extending'across vthe bottom of the hood, supporting means for the hood provided with a of passages extendingoutwardly. from 4the sump and respectively adapted to communicate attheir outer ends With a plurality lof molds arranged about thev hood.

5. In'y an apparatusfor .casting metal, av

hoodhavlng an opening in its upper'part to vform an air-tight seal, means for exhaustsump-beneathsaid element, and' a plurality l adapted for the lreception of lthe' nozzle plate .of a casting ladle, a fusible element. extending across and closing `the lower end of the hood, a central runner disposed .within the hood and adapted to receive metal from the ladle through said nozzle plate, the base of said runner resting on `said fusible elel ment', 'supporting mans'for the hood disposed therebeneath and provided with a sump below said'` runner, and a plurality of closed passages extending outwardlyffrom said sump andf respectively adapted to communicate molds arranged about the hood.

6.,An apparatus for casting metal com and adapted to forman air-tight closure therewith and the lower end of the hood being open, a stool disposed beneathand affording support to the hood, a fusible ele-l ment interposed between the hood and the stool and extending across and closing the lower end of the former, means for causing a substantial vacuum within the hood when the nozzle plate is positioned lin the openingr in the upper endrthereof, and ymeans for conducting metal from a point below saidy fusible plate to a mold disposed outside of the hood. v f

7. An apparatus for casting metal comprising a casting ladle hav-ing a pouring nozzle and a nozzle plate whose surface is of substantiallysemi-spherical contour disposed adjacent thereto, a hood open at the i brottom and having an 'aperture' in its upperv g end adapted for the reception of the semi- `spherical portion lof said nozzle plateto thereby form an air-tight closure therewith,.a stool for supporting the hood in up- 4rightr position, a fusible element interposed between the hood and the stool and extending across and closing the bottom ofv the hood against the admission of air, a central runner disposed within the hood extending .to the fusible element and adapted to receive metal through the. nozzle plate,'means forV creati-ng a vaguum within the hood, and means formed in the stool for conducting I molten metal from a point belowsaid element toa moldydisposed adjacent the'outside'of the hood. l 8. An7 vpparatusl `for casting lmetal comprising a casting ladle having a nozzleI and i a nozzle plate provided with a semi-s herical surface, a vertically extending hoo hav- I ing an opening in its upper end containing a packing rin generally conforming tol the Surface of said nozzle plate and adapted to form air-tight closure therewith when the opening, a: stoolforming a support for the hood and provided with/a sump beneath` the hood andla plurality of passages formedy in` its body, extending outward fromthesump and respectively terminating at the surfacel of the stool at points .beyond the wall of the hood, a fusible plate interposed during its yof metal save at its leading 11. The methodv of bottom casting a plubetween the lower end of the hood and surface of the stool and forming an airtight closure for t-he bottom of the former,

a hollow central (runner 'positioned withinV the hood -upon said plate andadapted to receive the molten metal when teemed from the ladle through thenozzle, and means for creating a reducedppressure in the hood kand lower ends, creating a zone of reduced pressure below the body of metal, then teem' ing the metal through said zone to el'ect an appreciable drop in temperature durin its 'passage from the -top tothe bottom o the zone, causing the metal to create an exit passage for itself from the bottom .of the zone and to thereafterpform a seal for the passage so created to prevent entrance of air to the zone, continuously withdrawing from the zone theA gases given off by the metal upassage therethrou h, and finally conducting themetal to thell) mold while preventing `access of air to the stream of metal Vsave at its leading end. 10.v The method of bottom casting afn inot which comprises thesteps-of supporting a body of the molten metal from which the ingot is to be formed in the vicinity' of Ottom of thev pressure below the body of metal, teeming the metal through said zone in a relatively' thin stream whlle preventing the laccessof air to the metal, causing the metal to create an outlet for itselffrom the bottom of the zone, continuously withdrawing from the zone the gases given 'off by the metal during its passage therethrough, and finally conducting the metal to the lbottom of the mold while preventing access-of air o the stream rality lof ingots simultaneously which comprises the steps of sup orting a body of molten metal from whlch be formed in the-vicinity of a .group of molds respectively rovided with openings in their upper and ower ends, .teemingthe metal in av relatively thin stream throughv a zone Iof reduced pressure While preventing plate is brought intojuxtaposition with the'access of air to the metal, continuously re` moving from said zone the lgases given olf by. the metal during its passage there. through, finally conducting the metal from said-zone in individual streams to-'the botthe ingots are to molds open at their upper Vand lower ends,

12. The method of bottom casting a plurality of ingotsy simultaneously which comprises the steps of supporting a body of the molten metal from which the ingots are to be formed in the vicinity of a plurality of creating a zone of reduced pressure below the body of metal, teeming the metal in to said zone5 permitting the metal to create for itself an outlet from said zone and to then seal said outlet against the entrance of air into the zone, and inallyconducting the metal after its exit from the zone through `said voutlet to the bottoms of the several molds in individual streams while prevent-- ing access of air to said streams save at their leading ends. l l

13. The method of bottom casting a plurality of ingots simultaneously which comprises the steps of supporting a body of the molten metal from which the ingots are to be formed in the vicinity of a plurality of molds respectively having` openings at their tops and bottoms, creating a zone of reduced pressure below the body of metal, teeming the metal into said zone in a relatively thin stream While preventing access of air thereto, permitting the metal to create for itself an outlet from said zone, thereafter utilizing `the stream of metal itself to form a seal In witness whereof, I have hereunto set my hand this 12th day of November, 192.6.

IJAMES M. 'ifIELsorL`

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