US2708298A - Apparatus for casting metal billets and the like - Google Patents

Description

May 17, 1955 L. M. EcKEs APPARATUS FOR CASTING METAL BILLETS AND THE LIKE Filed June 27, 1952 2 Sheets-Sheet l lull-W11 INVENTOR.

BY V

E El?! A TTO/FA/E Y May 17, 1955 L. M. BECKES 2,708,298

APPARATUS FOR CASTING METAL BILLETS AND THE LIKE Filed June 27, 1952 2 Sheets-Sheet 2 INVENTOR.

BY MBAMQLQM A TTORNE Y United States Patent APPARATUS FOR CASTING METAL BILLETS AND THE LIKE Lloyd M. Beckes, Union, N. 1., assignor to American smelting and Refining Company, New York, N. Y., a corporation of New Jersey Application June 27, 1952, Serial No. 296,035

3 Claims. (Cl. 22-78) This invention relates to the making of castings and more particularly to castings of shapes suitable for further processing, as for example, billets or slugs of tin-lead solder for extrusion into wire.

According to prior practice, billets, such as those in question, are usually cast by hand-pouring the molten solder into vertical, cylindrical, water jacketed molds having a lower end closure. The billets are discharged from the molds after cooling and solidification of the solder, by inverting the mold, if trunnion mounted; or by releasing the bottom closure plate if the molds are mounted in a fixed position.

Billets cast by this prior practice have several objectionable characteristics, among them being dross or oxide inclusions, air inclusions, cold shuts, and starved areas, all of which constitute imperfections in the extruded product, which result in difiiculties in subsequent processing.

Objects of the invention are to overcome the objection of prior practices and, at the same time, reduce cost, im-

prove reliability of manufacture and produce a better finished product.

Other objects of the invention are to produce billets possessing improved physical and metallurgical properties, particularly those of uniformity of dimension, freedom from dross or oxide inclusions and starved areas,

and so far as possible, reduced segregation of constituent metals.

Other objects will be apparent from the following description and claims when considered with the accompanying drawings in which:

Fig. 1 is a schematic central vertical section through j.

Fig. 2 is a larger scaled central vertical section of the invention, showing the mold in the discharge position; Fig. 3 is a fragmentary plan section taken on line 3-3 of Fig. 2;

Fig. 4 is a fragmentary vertical section taken on line hole 27 through which the solidified billet drops.

ice

circulates molten metal through the header 12, flow being indicated by the arrow. Hand operated valve controls the pressure of the molten metal delivered to the mold 17 while servo-motor-operated control valve 16 is open. Closure of valve 16 raises the metal pressure in header or manifold 12 for the purpose of filling the mold 17.

This arrangement is, in general, similar to that disclosed in Palmer and Beckes Patent No. 2,459,892, dated January 25, 1949. Although a single mold 17 is shown, it will be understood that any suitable number of molds 17 may be distributed along the length of manifold 12 so that the same metal circulating system may feed the several molds.

The molding machine will first be only generally described. It comprises a stationary frame supporting a fixed mold plate 2%? having a fill port 26 to which the header 12 is connected. Plate 20 also has a discharge Slid ably mounted on mold plate 20 is slide plate 21, the latter having secured thereto a vertically disposed mold cylinder 22. The stationary frame supports a mold cover 23 normally held spaced from the top of the mold cylinder 22 by springs 49.

A servo-motor cylinder 24 is mounted on the stationary frame for the purpose of pushing the mold cover 23 down against the mold cylinder 22 before the latter is filled with molten metal. A double acting servo-motor cylinder 25 is connected to slide plate 21 for moving mold cylinder 22 from filling position over port 26, as shown in full lines in Fig. 1, to discharge position centered over hole 27, as indicated by the dot-and-dash lines in Fig. 1. The construction and operation will be described more fully below.

Referring now also to Figs. 2 and 3 for a more complete description, the casting machine comprises a stationary frame made up of suitable structure members, indicated in general by 30. The frame supports stationary mold plate 20. Slide plate 21 slides in guides or ways 31 secured to mold plate 20. Double acting hydraulic cylinder 25 is secured to the stationary frame and has a piston rod 32 secured to slide plate 21. A stop member 33 secured to the frame limits movement of slide plate 21 in one direction in which position the mold cylinder 22 is exactly centered over the discharge hole 27. A suitable stop limits the movement of the slide plate in the other direction to approximately center the mold cylinder 22 f 7 over the feed port 26.

44 of Fig. 2, illustrating the sealing ring at the feed port of the pressure header, through which the molten In the following description, specific terms will be used i for purposes of explaining the embodiment used toillustrate the invention, but these and broader terms are used in the claims which are intended to define the invention in as broad a scope as the prior art will permit.

Referring now to the drawings, and more particularly to the schematic diagram of Fig. 1, the kettle 10- contains a bath of molten metal (for example, tin-lead solder) which is to be cast by the casting machine.

The metal is kept in molten condition at suitable temperature by fuel burner 14. Pump 11 driven by motor 13 continuously part of a cooling jacket.

It will be noted that slide plate 21 has a part providing a cover for feed port 26 in the billet discharge position illustrated in Fig. 2. The billet in this figure, indicated by 44, is shown being discharged by dropping from the mold by gravity.

Mold cylinder 22 comprises an inner cylinder 35 secured to baseplate 21. Wall 35 supports upper ring 36. Outer cylinder 37 surrounds inner cylinder 35 forming Outer cylinder 37 is connected to a lower ring 38 and to an upper ring 39. Lower ring 38 is suitably connected to slide plate 21; upper ring 39 is suitably connected to ring 36.

It willbe noted that outer wall 37 extends into annular recesses 40 and 41 respectively. Pipes 42 and 43 are connected to rings 38 and 3Q which in elfect form annular ducts. It will be understood that pipes 42 and 43 are connected through flexible conduits to suitable stationary supply and discharge water pipes (not shown), permitting the mold cylinder to move back and forth between fill and discharge positions.

It will be understood that the various parts of the mold cylinder 22 may be connected together in any suitable manner. As indicated, welding is relied upon in most instances. The water jacket permits only a thin layer of water throughout substantially the entire cooling area of the mold cover 23.

amazes 3 that part of the mold in contact with the hot molten metal. This permits high efliciency cooling using high velocity water how with reduction of skin effect.

Cold water is fed in through upper pipe 43 into the upper part of the jacket and withdrawn from lower pipe' 42 out of the lower part of the jacket; this makes the upper part of the mold coolest to obtain directional cooling of the casting from the top down so that the lower part of the billet will freeze last.

Mold cover 23 comprises a lower plate 46 and upper plate 47', the plates are so shaped as to form a thin water jacket space therebetween. A central boss 53 is secured to upper plate 47 to transmit the pressure exerted by air cylinder 24 to lower plate 46. Pipes 50 and 51 provide for circulation of cooling water. These pipes are connected through flexible connections to suitable stationary pipes to permit constant circulation through the water jacket, and yet allow the mold cover 23 its limited upand-down movement, as described below.

The mold cover 23 is supported by studs 48 screwed 2 into the top of the cover and slidably engaging the adjoining frame members Sd. Helical springs 49 are interposed between the heads of the studs 48 and the frame members to yielda'oly hold the mold cover 23 in uppermost position, away from the mold cylinder 22, as indicated in Fig. 2. Air cylinder 24 is secured to the adjacent frame member 39 and has a piston rod 52 connected to Application of air to the cylinder 24 forces the cover down against the mold when the latter is infilling position. When air is released from the cylinder 24, the springs 49 raise the cover 23 ofi the mold cylinder 22.

For the purpose of permitting air to escape from the mold during filling with molten metal, the top of the mold cylinder may have one or more grooves, indicated by 55 -in Fig. 2. A brush 56 may be secured to the adjacent frame member 30, which brush sweeps out the grooves, as

the mold cylinder moves back and forth between fill and discharge positions. This insures always having open grooves by removing any fin of cast metal which may end 61 engaging seat 59. The inner surface of the sealing ring 69 is conical and extends between a relatively large feed opening in the wall of header 12 to the'relatively small feed port 26. a

It will be noted that the engagement between ring 60 and mold plate 2% is of limited area; also that clearance space is provided between the ring 60 and bend 57, on

the one hand, and the underside of mold plate 20, on the other hand, as indicated particularly in Figs. 4 and 5.

The sealing ring 6!) is preferably of soft iron and has machined and lapped surfaces engaging similarly treated surfaces on header 12 and mold plate 2i). The material of the ring 69, as well as other parts of the apparatus contacting the molten metal, is of such nature as to avoid any chemical action by the molten metal on the machine.

The sealing ring 60 is clamped in position by a clamping arrangement comprising a bar 65 and a pair of studs 66 screwed up into the mold plate 20. The bar 65 is slidably mounted on the reduced ends of the studs 66 and is 'urged upwardly by springs 67 disposed under the bar'65 .and acting against nuts on the ends of the studs.- A set screw 68 threaded into the bar 65 presses the header 12 upwardly.

The meeting spherical surfaces on the sealing ring 60 and header 12 permit any slight adjustment of the header as it is clamped up into position, while insuring a liquidtight engagement between the ring and its connected parts,

all)

. 4 V regardless of exact position of the header. The return pipe of the molten metal circulating pipe is supported by the frarne 30 at 63 in Fig. 2.

Operation The various movements of the parts may be controlled by a workman initiating each movement by admitting fluid to the several cylinders at the proper times Or, the.

control cylinder may be operated by a suitable electrical system of timers, relays, switches, solenoid operated valves, etc. (not shown). 7

A description of the operations and movements in a complete cycle follows:

Assume that the flow of molten metal has been established in the header 12 and circulating piping, and that the rate of flow has been adjusted by the hand control valve 15 so that molten metal within the inlet port 26 stands at a level just below the top surface of the mold plate 259. The electrical and pneumatic-hydraulic circuits are so arranged that, when the electrical control system is tie-energized, the mold 22 is in the discharge position and the inlet port 26 is blanked off by the bottom part or the slide plate 23 (see Fig. 2

When the electrical control system is energized, the hydraulic cylinder 25 is operated to cause the mold 22 to move from its discharge to its fill position, uncovering the inlet port 26. The fill position is shown by the position of the mold cylinder 22 in full lines in Fig. 1.

When the mold cylinder 22 reaches its 111 position, a switch (not shown) is actuated, causing the mold cover 23 to move downward against the top of the mold."

When the mold cover 23 has completed its downward movement, another switch (not shown) is actuated, causing the pressure control valve 16 to start to close. As the pressure control valve 3.6 closes, molten 'metal pressure within the header. 12 increases, causing metal to flowinto and fill the mold. The extreme pressure in the header is maintained during the time required for solidification of the metal in the ,mold so as to feed the casting with hot metal.

When the necessarytime for solidification of the metal in the mold has elapsed, a timer (not shown) in the electrical control system acts to cause the pressure control valve 16 to open, lowering the pressure in the header 12 to its preset low value and, at the same time, causing the mold cover 23 to rise from the top of the mold. When the mold cover 23 reaches itsextreme release position, a switch (not shown) is actuated, causing hydraulic cylinder 25 to move the mold cylinder 22 on mold plate Ell-from its fill position toward its discharge position.

When the mold cylinder 22 reaches its discharge position, which is in register with clearance hole 27 in the mold plateZt), the billet 4-4 falls by gravity from the mold sealing ring.

Comments 7 It will be noted that the area of contact between the 'r'nold plate 2% and the sealing ring 69 is relatively small, and so tends to reduce the amount of heat transmitted from the sealing ring to the mold plate. It will also be noted that the area of contact between the sealing ring 69 and the header 12 is relatively large and so tends to favor the transmission of heat from the header to the Also, the top of the sealing ring 61 is closeto the top of the mold plate 2%. The net result of such an arrangement is, in effect, to bring the areas within the header, where the metal is always molten, into the closest possible proximity to areas within the mold cavity where it is desired to cool and solidify metal admitted through the inlet port.

In other words, the'i. yention brings the areas of molten and solidified metal as close together as possible physically and, at the same time, has these areas as far apart as possible thermally.

Through the use of a sealing ring, proportioned as outlined above, the following favorable conditions for the production of a sound casting are obtained, so far as the relationship between the header and the mold are concerned: a minimum loss of heat from the molten metal circulating through the header and flowing to the mold, making it possible to maintain more nearly uniform temperatures at the inlet ports when multiple molds are used; the ability to keep the lower portions of the mold at a lower temperature, thus promoting more rapid cooling of the casting; the ability to establish a quite sharp line of demarcation thermally, at or near the molten metal entry port, so that molten metal, which has entered the mold, may be quickly cooled and solidified; the ability to maintain the metal within the entry port and sealing ring in a molten state and, by so doing, make available a path of supply for molten metal under pressure to feed to the casting to compensate for the decrease in volume due to cooling and solidification.

The invention also provides the following advantages especially important in the casting of billets: (1) bottom filling of the mold; (2) maintenance of the maximum molten metal pressure at the mold inlet port during the time required for cooling and solidification of the casting so as to feed hot metal to the casting to compensate for the shrinkage of solidification, and (3) rapid cooling applied in such a manner as to provide for directionally controlled progressive solidification of the casting from top to bottom of the mold.

The use of this invention provides considerably more leeway in maintaining correct timing of the several events, correct temperatures of mold and circulating metal for any particular mold shape or size, and particular composition of cast product.

While the invention is particularly adapted to the casting of white metals and lead alloys, it will be understood that the principles thereof are applicable generally to the casting of other metals and alloys which present problems similar to those encountered in casting white metal. Further it will be appreciated that various omissions, substitutions and changes may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. In a molding apparatus for casting molten metal and the like having a stationary frame, a mold plate secured to the frame, a mold charging position on said plate, a mold discharge position on said plate spaced from said charging position, a mold having an opening in one end thereof slidably mounted on said end on said plate and being capable of being slid on said plate from the charging position to the discharging position, a molten metal inlet port passing through the plate at the charging position thereon and in communication with said mold opening when the mold is in charging position on the plate, and a conduit for supplying molten metal to said inlet port, the improvement comprising a recess in said mold plate encompassing said port on the side of said plate which is opposite to that facing the mold, a seat on said mold plate in said recess concentric with said port and in close proximity to the surface of said plate facing the mold, a portion of said conduit being disposed in said recess, a molten metal outlet in said portion of said conduit generally aligned with said port, a seat on said conduit encompassing said outlet, a sealing ring disposed in said seats, the contact surface between said ring and said conduit seat being larger than the surface contact between said ring and said mold plate seat, said ring being otherwise spaced from said mold plate and said conduit also being spaced from said plate, thereby to promote heat fiow into said sealing ring and to reduce heat flow from said ring to said mold plate.

2. In a molding apparatus for casting molten metal and the like having a stationary frame, a mold plate secured to the frame, a mold charging position on said plate, a mold discharge position on said plate spaced from said charging position, a mold having an opening in one end thereof slidably mounted on said end on said plate and being capable of being slid on said plate from the charging position to the discharging position, a molten metal inlet port passing through the plate at the charging position thereon and in communication with said mold opening when the mold is in charging position on the plate, and a conduit for supplying molten metal to said inlet port, the improvement comprising a recess in said mold plate encompassing said port on the side of said plate which is opposite to that facing the mold, a seat on said mold plate in said recess concentric with said port and in close proximity to the surface of said plate facing the mold, a portion of said conduit being disposed in said recess, said portion of the conduit comprising a return bend having a molten metal outlet therein in general alignment with said port, a seat on said conduit encompassing said outlet, a sealing ring disposed in said seats, the contact surface between said ring and said conduit seat being larger than the surface contact between said ring and said mold plate seat, said ring being otherwise spaced from said mold plate and said conduit also being spaced from said mold plate, thereby to promote heat flow into said sealing ring and to reduce heat flow from said ring to said mold plate.

3. Apparatus according to claim 2 in which said mold plate is horizontally disposed, said mold is slidably mounted on the upper surface of the mold plate, and said recess comprises an annular recess and larger recess encompassing the annular recess, said annular recess providing the said seat on the mold plate for said ring and the larger recess providing space for the portion of the circulating conduit disposed therein.

References Cited in the file of this patent UNITED STATES PATENTS 180,124 Guels July 25, 1876 471,527 Madden Mar. 22, 1892 543,700 Potter July 30, 1895 934,940 Shantz Sept. 21, 1909 1,318,558 Held Oct. 14, 1919 1,912,981 Hoy June 6, 1933 1,913,945 Morris et a1 June 13, 1933 1,950,568 Richards Mar. 13, 1934 1,952,201 Flammang et a1 Mar. 27, 1934 2,459,892 Palmer et al. J an. 25, 1949 2,526,753 Huck Oct. 24, 1950

Claims (1)

1. IN A MOLDING APPARATUS FOR CASTING MOLTEN METAL AND THE LIKE HAVING A STATIONARY FRAME, A MOLD PLATE SECURED TO THE FRAME, A MOLD CHARGING POSITION ON SAID PLATE, A MOLD DISCHARGE POSITION ON SAID PLATE SPACED FROM SAID CHARGING POSITION, A MOLD HAVING AN OPENING IN ONE END THEREOF SLIDABLY MOUNTED ON SAID END OF SAID PLATE AND BEING CAPABLE OF BEING SLID ON SAID PLATE FROM THE CHARGING POSITION TO THE DISCHARGING POSITION, A MOLTEN METAL INLET PORT PASSING THROUGH THE PLATE AT THE CHARGING POSITION THEREON AND IN COMMUNICATION WITH SAID MOLD OPENING WHEN THE MOLD IS IN CHARGING POSITION ON THE PLATE, AND A CONDUIT FOR SUPPLYING MOLTEN METAL TO SAID INLET PORT, THE IMPROVEMENT COMPRISING A RECESS IN SAID MOLD PLATE ENCOMPASSING SAID PORT ON THE SIDE OF SAID PLATE WHICH IS OPPOSITE TO THAT FACING THE MOLD, A SEAT ON SAID

Images