US3196503A - Apparatus for pressure pouring of cast metal articles - Google Patents

Description

y 1965 E. Q. SYLVESTER 3,196,503 APPARATUS FOR PRESSURE PQURING OF CAST METAL ARTICLES Filed Dec. 26. 1961 2 Sheets-Sheet l INVENTOR.

@iz muna/ wesiw July 27, 1965 E. Q. SYLVESTER APPARATUS FOR PRESS URI] POURING OF CAST METAL ARTICLES Filed Dec. 26. 1961 2 Sheets-Sheet 2 a a e/e,

United States Patent Isl.)

Filed Dec. 26, 1961, Ser. No. 161,936 6 Claims. (Cl. 22-69) This invention relates generally to the art of casting metals and more specifically to a novel method and apparatus for pressure casting steel articles.

As a result of attempts made to cast steel articles which are suitable for direct drawing, extrusion or rolling it :has been found that surface imperfections of the cast article can be substantially minimized if the molten metal is pressure poured into a mold which is at least slightly inclined from the horizontal so as to have its inlet at the lower-most portion thereof. As a result of this general arrangement, it is possible to control the rate of flow of molten metal into the mold cavity so as to result in non-turbulent flow thereby preventing, for example, splashing and the consequential surface defects arising therefrom.

However, the general arrangement as described above usually requires a riser communicating with the uppermost portion of the mold cavity, in order to feed additional metal into the mold cavity as the metal therein begins to solidify and shrink, and a shut-off mechanism at or near the inlet end of the mold cavity in order to prevent the reverse flow of molten metal out of the cavity upon subsequent disengagement of the pressure pouring tube and before solidification of the cast article.

Such additional requirements as risers and in-gates are generally undesirable in that they usually result in greater manufacturing costs. For example, even neglecting the costs of actually adding a riser and in-gate to a mold assembly, it can be seen that additional costs are incurred by virtue of the prolonged pouring operation. That is, a riser placed at the upper-most end of the mold cavity must be filled with metal which is poured into the mold from the opposite end. Accordingly, the actual mold filling time is the total time required to fill both the mold cavity and the riser cavity. Also, it is apparent that, since the riser is above the uppermost portion of the cavity, a greater pouring pressure will have to be employed in order to offset the pressure head of the metal in the riser.

Shut-oli mechanisms, usually being at least to some degree in the general path of molten metal as it flows into the mold cavity, are often subject to damage caused by warpage and/ or erosion.

Accordingly, an object of this invention is to provide a novel apparatus for pressure casting metal articles which eliminates the need of a conventional riser and a conventional shut otf mechanism.

Other objects and advantages of this invention will become apparent when reference is made to the following description and drawings, wherein:

FIGURE 1 is an elevational cross-sectional view illustrating a mold assembly and pressure pouring apparatus constructed in accordance with the teachings of this invention;

- FIGURE 2 is a cross-sectional view taken substantially on the plane of line 2-2 of FIGURE 1 and looking in the direction of the arrows;

FIGURE 3 is an elevational cross-sectional view illustrating a second embodiment of the invention;

FIGURE 4 is a fragmentary side elevational view, partially in cross-section, illustrating another embodiment of the invention; and

FIGURE 5 is a fragmentary end elevational view, par- 3,1965% Patented July 27, 1965 "ice tially in cross-section, of the invention as shown in FIG- URE 4.

Certain details are omitted from one or more figures for purposes of clarity.

Referring now in greater detail to the drawings, FIG- URE 1 illustrates a mold assembly 10 comprised of cope and drag sections 12 and 14 which cooperate generally with an end member 16, which may be gas permeable, in defining a mold cavity 18. The elements comprising the mold assembly may, of course, be retained in functional relationship by any suitable clamping means.

An inlet assembly 20, comprised of an outer housing 22 containing a lower layer of graphite 24 which in turn supports layers of firebrick 26, is secured in any suit-able manner to the mold assembly 10. A pressure pouring ladle structure schematically illustrated at 28 has its pouring tube 30 extending upwardly therefrom. The end 32 of the pouring tube is formed of spherical shape so as to be received within a similar spherically fomned recess 34 at the bottom of assembly 20. Chamber 36 which is formed by the firebrick 26 within the assembly 20 and in communication with mold cavity 18, also communicates with the pressure pouring ladle 28 as by means of pouring tube 30 and conduit portion 38 retained within assembly 20. Preferably, conduit portion 38 is comprised of a refractory mate-rial such as a clay-graphite mixture.

A refractory wall 40 serves to divide the general chamber 36 into two smaller chambers 42 and 44 which are interconnected by means of a clearance existing between the top 46 of the wall 40 and top surface 43 of the general chamber.

Operation After the mold assembly 10 and inlet assembly 20 are secured to each other, they are brought into functional engagement with the pressure pouring ladle 28 by bringing the coacting spherical surfaces 32 and 34 into mating relationship. The mold assembly 10 and inlet assembly 20 are then pivoted about surface 32 of the pouring tube 30 in a generally clockwise direction, as by positioning means such as, for example, a hydraulically or pneumatically actuated piston assembly 50, until the mold cavity is inclined about three degrees from the horizontal. The exact number of degrees of inclination will, of course, have to be determined in each particular case since, as will become apparent, inclination will be determined from such factors as, for example, the height of the wall 40 and length and height of the mold cavity 18.

Next, fluid pressure from a suitable source 52 is directed, as by means of conduit 54, to the ladle 28 causing the molten metal therein to flow upwardly through the pouring tube 30 and conduit portion 38 into chamber 44 from where the metal flows through the clearance between the top 46 of wall 40 and surface 48 into chamber 42 and mold cavity 18. Any air or gas ahead of the molten metal is, in the embodiment illustrated, forced out of the mold cavity 18 through the gas permeable member 16.

Pressure pouring of the molten metal continues as described above until the entire mold cavity 18 is filled, at which time mold assembly 10 and inlet assembly 20 are pivoted about spherical surface 32 in a counter-clockwise direction until the mold cavity is inclined downwardly about one or two degrees from the horizontal. The exact number of degrees will, of course, as previously discussed, be dependent on the physical characteristics of the particular apparatus employed. After the mold assembly 10 assumes this position, the application of super-atmospheric pressure is terminated and further upward flow of molten metal out of ladle 28 is prevented. As a consequence of the termination of pressure, the molten metal existing generally in chamber 44 and conduit portion 38 flows downwardly into the ladle 28. However, the metal contained within chamber 42 is retained therein by means of wall 40 whichacts as a weir. The entire mold asformed to curve in two directions; that is, it curves downsem-b-ly 10 and inlet assembly may then be disengaged from the pouring tube and transported by any suitable carriage means to another area where the molten' metal can solidify.

An important feature ofthe above described method and apparatus for carrying out the method is that'a riser is automatically formed by the inversion of, the mold assembly afterfilling' of the mold cavity. That is, the'molwardly and away-from the conical seat 110 so as to cornmunicate between the seat 118 and the mold cavity 80. Preferably, conduit 108 is formed of a diameter sumcient to enable the placement therein of segmented arcuate sections of clay-graphite inserts 116. Such inserts could, of course, be generally tubular andcomposedof split cylindrical mating upperandl-ower portions.

ten metal retained within chamber 42 by the wall 40 continues to feed additional molten metal to the cavity 18 as the metal therein undergoes solidification and resulting shrinkage. Another important feature, which may not be immediately apparent, is that the metal within chamber 42 acts as a more perfect riser than those conventionally employed. That is, since the metal within the The mode of operation is of course similar to that, of the structures d-isclosed'by FIGURES 1, 2 and 3. That is,

before pouring of molten metal, the mold assembly 74 and inlet assembly 82 are rotated clockwise (as viewed in FIGURE 4) about the end 112 of pouring tube 114 so as to raise the extreme'end of the mold cavity some predeterchamber 42 did not have to travel the entire lengthof.

the mold cavity, the heat of the metal is retained to' a higher degree thereby preventingthetpossible prema ture solidification 'of the riser portion itself.

The inlet assembly 56 of FIGURE 3, which is a modi fication of the invention as illustrated by FIGURES 1 and 2, is comprised of an outer housing 58 containing an inner graphite member 60 which may be lined with refractory firebrick, 62 in a manner defining a chamber 64, the top'of which is prefer-ably formed by a removablegraphite cover 66. The lower portion of assembly 56is mined amount. After pouring is completed, the mold as sembly isrotated counter-clockwise thereby enabling the inlet conduit 1G8 and the reservoir of molten metal conassembly having a cavity therein of predetermined flow formed to provide-a spherical seating surface 68 for the "reception therein of the cooperating spherical surface 70 of pouring tube 88. t p

A refractory conduit 72, preferably made of a claygraphite mixture, is retained within the assembly 56 in a manner so as to be adapted for communication with'the pouring tube at its lower end while having its uppermost end projecting upwardly within'the chamber 64.

capacity to apouring tube, of a pressure pouring ladle assembly, comprising an outer housing, a layer of graphite contained within said housing at'the lower-most portion thereof, a refractory material lining substantially the remaining inner surface of said outer housing, a general chamber formed within said refractory material, a dividing wall within said general chamber dividing said general chamber into smaller first and second chambers, first Themethod'of operation as described with reference to. FIGURES l and 2' and the attendant benefitsflthereof apply to the embodiment of FIGURE 3. It should be notedthat upon lowering the extreme end of the mold as: sembly 10, the molten metaliwithintcha-mber 64 functions as a riser or reservoir and is prevented from flowin'g'back' into the ladle structure because of the upward projection of conduit 72 functioning as a standpipe, I,

A further benefit is derived from this modification.

passage means defined by the topof said wall'and the top :of; said general'chamber for providing an avenue of communicationibetween 'said first and second chambers,

a spherical surface-formed Within the bottom of said graphite layer 'externally the'reof for at times receiving therein an end of said pouring'tube in order to provide 7 for relative angular motion therebetween, a conduit coin- That is, as the molten-metal is fiorce'd upwardly through I conduit 72, any dirt particles therein'tend to rise to and remain at the surface of'the molten metalwithin chamber64. 7

The third embodiment of the invention as illustrated by FIGURES 4 and 5 is comprised of a mold assembly 74, having cope and drag sections 76 and 78 whichcooperate in forming a mold cavity 80 and are suitablysecured to upper andilower sections 84 and inlet assembly 82. p 1

The upper section 84 may'be comprised of an outer housing 88 containing a graphite member 90 therein which is formed to provide a lower mating surface'96 adapted to enact with the upper surface 98 of a graphite member 92 retained by housing 94 of the lower section 86. Pref-w erably, as seen in both FIGURES4 and 5, the lower. sur-' face 96 is formed to provide downwardly depending wedge-like key portions 180 and 102 which are received within complementary slots or' 'keyways v104*and 106,

respectively, f0r purposes of aligning sections 84 and 86.

with respect to-each other. 7

An inlet conduit 108 is formed "within the inletfassembly 82 by cooperative actioniof the up-per and' l ower sections 84 and 86. This is, comparatively arcuate passageways are formed within the lower surface of member 86, respectively, of the 1 municating with saidsecond chamber and terminating in said spherical surface, and a'second passage means for communicating between said first, chamber and'said cavity 'when said, mold assembly is functionally connected to said inlet assembly, said first' chamber and secondpassage means having flow capacity at least as great asthat ing steel comprising an outer retainer member, a refractory material liningthe inner surface, of said outer retainer member, a chamber formed within said refractory ma-- "'terial, a-removable refractory. cover member forming the upper-most portion'of said chamber, a connecting surmating, engagement to an end of said pouring tube, a

and the upper surface of the lower member 92 which",

when assembled, from the conduit 188; One end of -'conduit'108 terminates in a conical seat 110 formed to receive the conical end 112 of the pressure'pouring tube114.

Conduit: 108, as seen in both FIGURES 4 and 5, is

conduit portion having one endterminating in said surface and havingits other end projecting upwardly a sub-" stantial distance within said chamber, and passage means for communicating between said chamber and said cavity when said mold assembly is operatively connected to 'said inlet assembly, said passage means having flow'capacity 'at'least as great as that of saidcavity, the inlet, assembly being closed to the exterior except through said conduit and passage means. 7 t

- 3. An inlet assembly for'connection between amold assembly having a cavity therein and apouring tube of araaeoa a pressure pouring ladle assembly, comprising an upper and lower section, said upper section comprising an outer housing containing therein a refractory material with a lower mating surface formed thereon, said lower section comprising an outer housing containing therein refractory material with an upper mating surface formed thereon, a downwardly depending portion formed on said lower mating surface, a complementary recess formed in said lower mating surface adapted to receive said depending portion in order to align said upper and lower sections with respect to each other, a concave seat formed at the side of and partly within both of said upper and lower sections, said seat being adapted to at times pivotally receive therein an end of said pouring tube, and a conduit having one end terminating within said seat and having its other end adapted for communication with said cavity when said mold assembly is operatively connected to said inlet assembly, said conduit being comprised of complementary arcuate passageways formed within said lower and upper mating surfaces, said arcuate passageways being formed as to cause said conduit to curve in two directions down and away from said seat Whenever said mold assembly is in a substantially horizontal position, the inlet assembly being closed to the exterior except through said conduit.

4. An arrangement for pressure casting molten metal, comprising a stationary ladle assembly containing molten metal therein which is at times subjected to superatmospheric pressure; a stationary pouring tube having one end secured to said ladle assembly in a manner permitting communication with said molten metal and having its other end open and extending upwardly; a mold as sembly; a cavity formed within said mold assembly and defined generally by a cope, drag and a gas-permeable end member comprising said mold assembly; an inlet assembly operatively connected to said mold assembly and comprising an outer housing, a refractory material contained within said housing, a general chamber formed within said refractory material, a dividing wall Within said general chamber dividing said general chamber into smaller first and second chambers, first passage means defined generally by the top of said wall and the top of said general chamber for providing an avenue of communication between said first and second chambers, a concave surface formed on said refractory material externally thereof for at times pivotally receiving therein said other end of said pouring tube, a conduit communicating with said second chamber and terminating in said concave surface, second passage means for communicating between said first chamber and said cavity; a source of superatmospheric fluid pressure operatively connected to said ladle assembly for at times applying a superatmospheric pressure to said ladle assembly in order to force said molten metal out of said ladle assembly through said inlet assembly and into said cavity; and means for rotating said mold assembly and said inlet assembly about the pivotal connection existing between said other end of said pouring tube and said concave surface, said means for rotating said mold assembly being efiective to cause said cavity to assume a position upwardly inclined from said pivotal connection during periods when superatmospheric pressure is applied against said molten metal and also being effective to cause said cavity to assume a position downwardly inclined from said pivotal connection after the cavity is filled with said molten metal.

5. An arrangement for pressure casting molten metal, comprising a stationary ladle assembly containing molten metal therein which is at times subjected to superatmospheric pressure; a stationary pouring tube having one end secured to said ladle assembly in a manner permitting communication with said molten metal and having its other end open and extending upwardly; a mold assembly; a cavity formed within said mold assembly and defined generally by a cope, drag and a gas-permeable end member comprising said mold assembly; an inlet assembly operatively connected to said mold assembly and comprising an outer retainer, a refractory material contained within said retainer, a general chamber defined by said refractory material, a seating surface formed on said refractory material externally thereof for at times pivotally connecting with said other end of said pouring tube, a conduit portion having one end terminating in said seating surface and having its other end projecting upwardly a substantial distance within said chamber, second conduit means for communicating between said first chamber and said cavity; a source of superatmospheric fluid pressure operatively connected to said ladle assembly for at times applying a superatmospheric pressure to against the molten metal within said ladle assembly in order to force said molten metal out of said ladle assembly through said inlet assembly and into said cavity; and means for rotating said mold assembly and said inlet assembly about the pivotal connection existing between said other end of said pouring tube and said seating surface, said means for rotating said mold assembly being effective to cause said cavity to assume a position upwardly inclined from said pivotal connection during periods when superatmospheric pressure is applied against said molten metal and also being effective to cause said cavity to assume a position downwardly inclined from said pivotal connection after the cavity is filled with said molten metal.

6. An inlet assembly for pivotally connecting a mold assembly having a cavity therein to a pouring tube of a pressure pouring ladle assembly, comprising an outer frame-like housing, a refractory material contained within said housing, a mating surface formed externally on the bottom of said refractory material for pivotal connection with the upper end of the pouring tube, and passage means formed within said refractory material and having its terminal portion opening horizontally, said passage means being operative for communicating between said mating surface and said cavity when said mold assembly is operatively connected to said inlet assembly, said passage means having such great transverse dimensions as to provide a reservoir of molten metal therein, after the said cavity is filled, that is of substantially greater capacity than the cavity per unit length in the direction of flow of the molten metal, the inlet assembly being closed to the exterior except through said passage means.

References Cited by the Examiner UNITED STATES PATENTS 1,138,443 5/15 Bierbaum 2269 1,416,261 5/22 Bungay 2269 2,186,260 1/40 McWane Z2134 2,266,723 12/41 Fahlman 22-91 2,448,903 9/48 Miller 22-209 2,659,121 11/53 Easton et a1. 22134 FOREIGN PATENTS 237,730 10/ 11 Germany. 494,937 11/38 Great Britain.

WILLIAM J. STEPHENSON, Primary Examiner.

WINSTON A. DOUGLAS, ROBERT F. WHITE,

MICHAEL V. BRINDISI, Examiners.

Claims (1)

1. 6. AN INLET ASSEMBLY FOR PIVOTALLY CONNECTING A MOLD ASSEMBLY HAVING A CAVITY THEREIN TO A POURING TUBE OF A PRESSURE POURING LADLE ASSEMBLY, COMPRISING AN OUTER FRAME-LIKE HOUSING, A REFRACTORY MATERIAL CONTAINED WITHIN SAID HOUSING, A MATING SURFACE FORMED EXTERNALLY ON THE BOTTOM OF SAID REFRACTORY MATERIAL FOR PIVOTAL CONNECTION WITH THE UPPER END OF THE POURING TUBE, AND PASSAGE MEANS FORMED WITHIN SAID REFRACTORY MATERIAL AND HAVING ITS TERMINAL PORTION OPENING HORIZONTAL, SAID PASSAGE MEANS BEING OPERATIVE FOR COMMUNICATING BETWEEN SAID MATING SURFACE AND SAID CAVITY WHEN MOLD AS SEMBLY IS OPERATIVELY CONNECTED TO SAID INLET ASSEMBLY, SAID PASSAGE MEANS HAVING SUCH GREAT TRANSVERSE DIMENSIONS AS TO PROVIDE A RESERVOIR OF MOLTEN METAL THEREIN, AFTER THE SAID CAVITY IS FILLED, THAT IS OF SUBSTANTIALLY GREATER CAPACITY THAN THE CAVITY PER UNIT LENGTH IN THE DIRECTION OF FLOW OF THE MOLTEN METAL, THE INLET ASSEMBLY BEING CLOSED TO THE EXTERIOR EXCEPT THROUGH SAID PASSAGE MEANS.

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