US3318369A - Cooling system for casting wheel - Google Patents

Description

May 9, 1967 Filed Nov. 25, 1964 T. L. BRAY ETAL 3,318,369

COOLING SYSTEM FOR CASTING WHEEL 3 Sheets-Sheet 1 THOMAS L. BRAY GEORGE C. WARD ATTORNEYS JNVENTORS May 9, 1%? BRAY ETAL 3,318,369

COOLING SYSTEM FOR CASTING WHEEL Filed Nov 25, 1964 3 Sheets-Sheet 2 INVENTORS 3 THOMAS L. BRAY J GEORGE c. WARD l A r kin w Q 9 3 v/l /70 I ATTORNEYS May 9, 1967 v T. BRAY ETAL 3,313,3 9

COOLING SYSTEM FOR CASTING WHEEL Filed Nov. 25, 1964 s Sheets-Sheet 5 INVENTORS THOMAS L. BRAY GEORGE C. WARD ATTORNEYS United States Patent 3,318,369 COOLING SYSTEM FOR CASTING WHEEL Thomas L. Bray, Birmingham, Ala., and George C. Ward,

Carrollton, Ga., assignors to Southwire Company, Carrollton, Ga., a corporation of Georgia Filed Nov. 25, 1964, Ser. No. 413,930 7 Claims. (Cl. 164283) This invention relates generally to the continuous casting of metal and is more particularly concerned with the cooling of molten metal in the peripheral casting groove of the casting ring of a continuously rotating casting wheel.

Various types of apparatus for the continuous casting of metal by the use of a rotating casting wheel, the periphery of which is formed with a groove defining the cavity portion of a continuously moving mold, have long been known. In such devices molten metal is introduced into the moving mold cavity and the mold cavity is thereupon closed by an endless band engaging the peripheral edges of the mold wall and moving with the mold until the molten metal within the closed mold has cooled sufficiently to be a self sustained bar. Thereafter, the path of movement of the band diverges from the periphery of the wheel to expose the formed metal which, although at least substantially solidified, is sufliciently flexible to be easily drawn from the mold. A wide variety of mold cavity configurations which are defined by the groove shape and which determine the cross sectional characteristics of the cast metal, are available. Such shapes may range from a flat strip to a circular rod. Angular shapes are also conventional; thus, in the present presentation of the inventive concept, a bar of trapezoidal cross section is formed having a narrow base face, diverging side walls of greater width than the base, and a top surface formed by the mold closing band, the top surface being of greater width than the side faces or base.

Among the critically important problems encountered in continuous casting generally, and particularly in the use of casting wheels of the type herein referred to, is that of providing for the uniform progressive cooling of the metal as it travels within the wheel periphery from the point of molten metal reception by the casting groove to the point of extraction of the continuous, substantially solidified metal. It is well recognized in the metallurgical art that the uniform development of physical characteristics of strips, bars, rods, or wire drawn from the latter, is largel dependent on the grain structure developed during the cooling of the cast metal. The size and uniformity of grain structure is, in turn, a reflection of the rate and uniformity of cross sectional cooling as well as longitudinal cooling.

The continuous casting of bars of substantial thickness, as distinct from relatively thin strips in which the total surface is primarily formed by broad, fiat, easily cooled areas, presents specific problems. Heat dissipation by cooling of the side walls of the mold forming groove is required in combination with a commensurate rate of heat exchange by cooling of the inner transverse wall or floor of the groove in order to insure .a uniformity in cross sectional cooling.

Another problem with respect to heat transfer concerns the mold forming ring itself. This problem, in the absence of side wall cooling, has arisen due to the phenonemon known as thermal ratcheting. The phenonenon is exemplified in casting rings by successive incremental movements of the opposed walls of the grooves of such rings toward one another. As the temperature of the inner surfaces of the walls is elevated, the plasticity thus induced is opposed by the rigidity of the cooler outer portions of the groove walls. The compressive forces exerted on these heated walls by the metal band tend to move the walls toward each other at their peripheries and stress the walls. Upon cooling such stresses are relieved, but a permanent incremental deformation of the walls results. Repeated excessive heating and cooling of the walls, while inwardly stressed, results in a compounding of such incremental deformations to an extent precluding normal extraction of the cast bar from the groove without damaging the casting ring. Such damage requires repairing, reworking or replacement of the casting ring. By the use of the separate side wall heat exchange .means of the present invention ratcheting is inhibited.

Heretofore, liquid cooling systems within the casting wheel structure have been developed. Such prior art developments are exemplified by the United States Patent No. 2,710,433 of June 14, 1955 and United States Patent No. 2,865,067 of December 23, 1958, issued to Ilario Properzi, as well as United States Patent No. 2,928,141 of March 15, 1960, issued to Jack N. Portefield. However, such systems did not provide any direct heat exchange for the side walls, or any means of coordinating the rate of heat dissipation from contiguous transverse areas of the bar. Obviously, in angular bars such as herein depicted, the rate of heat dissipation along wider faces should be appropriately greater than the rate of heat dissipation from a narrower face in order to maintain a cross sectional uniformity of heat dissipation at the various surfaces of the bar.

The present invention is an improved cooling means for providing separated coolant channels within the casting ring adjacent the casting groove together with separately controllable coolant flow means for each, thus providing separately controllable rates of heat exchange along the separate walls of the casting groove.

The present invention comprises generally an annular casting ring presenting a peripheral mold cavity groove, in combination with a plurality of separate channels therein adjacent the casting groove side walls and floor, and independently controllable pressure means for supplying coolant to said channels and for controlling the velocity of the coolant fluid therethrough. The plurality of channels allows a large volume of coolant to pass adjacent the casting groove while segregating the flow so that the cooling rate around the casting groove can be selectively controlled. Moreover, the portions of the wall of the casting ring surrounding the channels pro vide a sufficient amount of strength to substantially prevent the closing of the casting groove by themovement of the side walls of the casting ring toward each- =other-.

These and other features and advantages of the present invention will be apparent from consideration of the following specification, taken in conjunction with the accompanying drawings wherein like characters of reference designate corresponding parts throughout and in which:

FIG. 1 is a front elevational view of the casting machine showing a first embodiment of the present invention;

FIG. 2 is a front elevational view of a casting machine showing a second embodiment of the present invention;

FIG. 3 is a cross-sectional view of the first embodiment of the present invention taken along the line 33 in FIG. 1;

FIG. 4 is a partial side view of the first embodiment of the present invention taken along the line 4-4 of FIG. 3 showing the inlet and outlet positions and the dam within the rear cooling channel;

FIG. 5 is a partial side view of the first embodiment'of the present invention taken along the line 55 in FIG. 3 showing the inlet and outlet posoitions and the dam within the front cooling channel;

FIG. 6 is a partial cross-sectional view of the first embodiment of the present invention taken along the line 66 in FIG. 3 showing the inlet and outlet positions and the dam within the bottom cooling chamber; and,

7 since they may be embodied in numerous other equivalent arrangements.

In that form of theinvention shown in FIGS. 1, 3, 4, and 6, the casting wheel 10 is presented as formed by laterallyspaced parallel right and left hand disks 11 and 12 respectively; Each disk is shown as formed with central bosses 13 and 14 respectively from which protrude hollow cylindrical supporting shafts 15 and 16 respectively. The shafts 15 and 16 are rotatably mounted in bearing sleeves 17 of opposed spaced supporting stanchions 18 through which the hollow shafts 15 and 16 extend for internal connection with' coolant fluid supply and discharge means hereinafter discussed. The internal face of the disks 11 and 12 adjacent their peripheries are formed with dovetailed recesses 19 to receive and secure the dove-tailed, inner side flanges 20 of the casting ring 21. Between the side flanges 20 there is provided an inwardly opening coolant channel 22 for directly cooling the transverse intermediateweb 23 which formsthe floor of the casting groove 24. Thechannel 22 formed between the inner side flanges 20. is closed by an inner, annular cover plate 25. The

' side wall coolant channels 33 and 34 are defined between .inner and outer flanges 36, together with cover plates 37 and 38 for the right hand and left hand channels 33 and 34 respectively.

For supplying coolant under pressure to cooling channels 22, 33 and 34 for dissipating heat from the casting groove 24, a source 40 (FIG. 1) is provided. A pipe 41 having flow control valve 42 therein extends from the source 40 to a central fluid passage 43 within the left hand supporting shaft 16. From the passage 43, the fluid is delivered to the channel 22 by Way of elbow 44, flexible connector 45, and fitting 46 to the channel 22. From the channel 22, coolant fluid exits by way of the fitting 47, flexible connector 48 (see FIG. 6) and elbow 49 leading to exhaust manifold 50 extending through the right hand support shaft 15. From the exhaust manifold 50, the discharge coolant fluid from allrthe channels is discharged through the conduit 51 shown in FIG. 1. As indicated in -FIG.' 1, the inlet fitting 46 for the channel 22 extends through the cover plate 25 of the groove 22 closely adja-.

cent the exhaust fitting 47. To insure the desired directionalflowof the coolant within the channel 22, shown as clockwise in FIG. 6, hence in the direction of travel of the periphery of the wheel, a dam 54 is provided in the channel 22 to restrain the fluid from counter-flow in counterclockwise direction. However, to insure complete filling of the channel, precluding air pockets therein, and for insuring uniform pressure throughout the channel, the dam 54 is formed with an intercommunicating port 55.-

For supplying coolant to the left hand coolant channel i 34, a separate intermediate passage 56 is provided in the left supporting shaft 16 to which coolant fluid is supplied from the pressure source 40 through the intermediate pipe 56 under control of the valve 57. From the intermediate 34, coolant fluid is delivered through connections indicated at 62 in FIG. 4, passes through and between the disks 11.

and 12 to the flexible connection 63 (FIG. 3), thence to the fitting 64 which is connected with the duct 65 of the boss 13 of the right disk 11, the duct 65 communicating with the exhaust manifold 50. A perforate dam 60a is provided in the channel 34 in the manner of the dam 60 of FIG. 6, whereby the direction of circulation is controlled and air bubbles in the channel 34 are precluded.

Similarly, the right hand coolant channel 33 is supplied with coolant from the outer passage of the left hand supporting shaft 16 which in turn is supplied with coolant fluid under pressure from the source 40 through pipe 71 controlled by valve 72. From the passage 70, the coolant fluid passes through the duct 73 of the boss 14, thence by Way of fitting 74, flexible tube 75 and elbow 76 to a transversely extending nipple 77 extending through and between the disks 11 and 12 to an elbow 7 8, nipple 79 andelb'ow 80 extending through the cover plate 37 of the right hand channel 33. As shown in FIG. 5, an exhaust nipple 81 mounted through the cover plate 37 discharges the coolant from the right hand channel 33 to the flexible connection 82, fitting 83 and duct 84 in the boss 13 to the exhaust manifold 50. A perforate dam 60b is provided in the channel 33 in the manner of the dam 60 for controlling circulation and for preventing air bubbles.

In the dissipation of heat from the groove 24 of that form of the invention shown in FIGS. 1, 3, 4, 5 and 6 it will be seen that not only are the walls 23, 31 and 32 cooled by separate coolant channels 22, 33 and 34 respectively, but that each channel is supplied through an independently controlled flow valve. Such independent control regulates the flow velocity in each channel. In heat exchange systems of the present type it is well recognized that the velocity of the cooling medium is an important factor to be considered along with volume and initial temperature .of such medium. Hence, in the present arrangement the flow valves 42, 57 and 72 may be separately adjusted to insure the desirable flow velocity appropriate to the specific requirement of each wall for its demand for heat dissipation.

In that form of the present invention presented in FIGS. 2 and 7, the basic construction of the left side of the casting wheel is substantially similar to the construction of the wheel of FIG. 3. In FIG. 7, like numerals represent like parts heretofore referred to in FIG. 3; thus, the wheel of FIG. 7 includes the left hand disk 12 with the boss 14 together with the left hand supporting shaft 16. The bearing sleeves 17 and the supporting stanchions 18 are also as shown in FIG. 3. However, in lieu of the right hand disk 11 of FIG. 3, a vertically disposed retaining annulus 100' is provided, secured and spaced as in the right hand disk 11 of FIG. 3, by nuts and bolts 26 and 27. The casting ring 101 also departs from the teaching of the construction of the casting ring 41 of FIG. 3 in that the ring 101 is of composite construction having a ring body 102 cast onto a casting groove forming liner 103 defining the casting groove 104. By this construction materials of different physical character particularly as to strength and heat conductivity can be employed. In the arrangement here shown, the heat exchange tubing for the coolant fluid, hereinafter discussed in detail, is in direct contact with the liner 103. v The important characteristic of the liner 103 is its heat conductivity which provides effective and eflicient heat exchange between the metal and the coolant tubes. On the other hand, since the cooling is. achieved by the tubes in contact with the liner 103, the heat conductivity characteristics of the material of the body 102 of the ring are not as critical as where the ring itself is the primary means of heat dissipation. Thus, in selecting a material for the body 102, heat conductivity can be neglected in preference to material of greater strength. While the invention is not restricted as to the method of forming the ring 102, the present construction lends itself to convenient formation by locating the coolant tubes in contact with the liner 103 along its external face, and casting the ring body material on the liner 103 so that the tubes are embedded in the body material, thus substantially welding the liner, tubes and body together.

The arrangement for the supplying and discharging of coolant fluid differs from the arrangement of FIG. 3 in that the left hand suporting shaft 16 defines a single internal coolant inlet flow passage 105 to be supplied by pipe 106 under control of flow control valve 107 (FIG. 2) from a fluid pressure source such as the source 40 of FIG. 1. In this form of the invention, the left hand support shaft 16 is extended to the right with its coolant inlet flow passage 105 extended therewith to a first integral crossbeam 108 having a radial duct 109 communicating with the inlet passage 105 at its inner end, and with a circular manifold 110 which is rotatable with the crossbeam 108 at its outer end. As hereinafter discussed, the supply manifold 110 delivers coolant to the various coolant supply pipes of the wheel 100. The support shaft 16 is further extended to the right by an intermediate solid section 111 which joins a second integral crossbeam 112. The crossbeam 112 supports a circular hollow coolant discharge manifold 113 which communicates by a duct 114 with the hollow terminal bearing end 115 to form a dscharge outlet for spent cooling fluid from the discharge manifold 113. The terminal bearing end 115 of the shaft 16 is supported for rotation in the right hand bearing sleeve 17 of the right hand supporting stanchion 18.

The coolant tubes in the casting ring 'body 102 and in contact with the liner 103 are segmental arcuate tube flights, each flight being independently supplied with coolant from the supply manifold 110. In the prseent form of the invention, four consecutive flights in quadrants of approximately 90 complete one consecutive annular series of flights. Further in the present presentation, two annular series are provided in contact with each side wall of the liner 103, and two annular series are provided in contact with the inner transverse wall of the liner. As hereinbefore mentioned, the arcuate segments of the coolant tubes are located in direct contact with the liner 103 for maximum heat exchange relation. Since the eflectiveness and efliciency of such heat exchange relation is high, at least substantially fulfilling the cooling requirements for the operation of the casting wheel, the material of the ring body may be of such material as to provide maximum strength as compared with materials which must fulfill high heat exchange requirements. It is further to be noted that, by the provision of multiple segmental coolant tubes, the body 102 is not subjected to the intense temperature changes which produce the thermal ratcheting phenomenon hereinabove discussed.

In the specific form of the invention presented in FIG. 7, an outer left hand side quadrantal flight of tubing in contact with the liner 103 is supplied with co0lant fluid from the supply manifold 110 by supply pipe 120. Therewith, an inner side tubing flight, which is in contact with the liner 103 on the right hand side of the wheel 100 is supplied with coolant fluid from the supply manifold 110 by pipe 121. Similarly, a left hand floor coolant tube in contact with the floor of the liner 103 is supplied with coolant fluid from the manifold 110 by pipe 122. It will be observed from the sectional view of FIG. 7 that the coolant fluid supply pipes 120, 121 and 122 are substantially in the vertical plane of the sec tion. Alternate cooling tubes to those already described are depicted in section, numeral 123 indicating the outer right hand side coolant tube, numeral 124 indicating the right hand floor coolant tube, and numeral 125 indicating the lower left hand side coolant tube. From this depiction it will be seen that the inner and outer spaced flights of tubing of the cooling system .provide for the relatively staggered relation of each pair of coolant circuits for the side walls and floor. The discharge of coolant fluid from each flight of tubing returns the 6 fluid to the discharge manifold 113. Thus, as indicated in the upper portion of FIG. 7, a discharge pipe 126 leads from the discharge end of the tube 123 to discharge coolant fluid from the tube 123 to the manifold 113; pipe 127 discharges fluid from a discharge end of the tube 124 to the discharge manifold 113; and pipe 127 discharges fluid from the tube 124, while pipe 128 discharges coolant fluid from the tube 125. In like manner,

the tubes supplied by the pipes 120, 121 and 123 discharge the coolant fluid to the discharge manifold 113 through the discharge pipes 129, 130 and 131. A like arrangement of coolant tubes, supply pipes and discharge pipes, whereby coolant fluid from the supply manifold circulates in a staggered quadrantal arrangement of pairs of tubes for each side wall and floor of the liner 103, is provided. In the interest of clarity and verbal economy, a repetitious identification of each .pi e delivering coolant to, and discharging coolant from, each tube depicted in the lower portion of FIG. 7 is omitted. It is believed clear from the foregoing that the arrangement of pipes for supply and discharge, and the arrangements of the tubes which are supplied and discharged by said pipes, is clear from the above descriptiOn of the specific pipes illustrated in the upper portion of FIG. 7.

An important feature of the arrangement of FIG. 7 is provision of means by which the rate of coolant flow to each quadrantal tube flight may be readily controlled. Thus, in operation, should heat exchange requirements vary as between quadrants of any series or as between series of quadrant flights, an adjustment of the coolant flow can be provided by the manual valves indicated at 132. Obviously, such facility of adjustment of fluid flow in relation to the heat exchange requirements will effect not only the quality of the cast bar, but also an economy in operation.

OPERATION From the foregoing it will be seen that, when a casting operation is in process with the first embodiment of the invention, as the casting wheel 10 rotates, the molten metal is poured into the casting groove 24 which is thereupon closed by the belt to complete the casting mold. The coolant is forced through the cooling channels 22, 33 and 34 under control of flow valves 42, 57 and 72 and is directed by the dams 54, 60a and 60b to flow out of the cooling channels through the connectors 48, 63 and 82 and into the exhaust manifold 50 and out of the casting wheel 10. Flow regulating valves 42, 57 and 72 provide any desired flow velocity through the cooling channels 23, 33 and 34 independently of one another, thereby producing the desired cooling rate on any surface at any point along the casting groove 24. As the molten metal progresses with the rotation of the wheel, the controlled cooling causes solidification of the metal to form a continuous bar of uniform physical characteristics.

In the second embodiment of the invention, as the wheel is rotated in the same manner as in the first embodiment of the invention, and as metal in a molten state is introduced into the casting groove 104, coolant flow, regulated by the valves 132, supplies coolant to the tube flights adjacent the liner 103. The coolant enters the tube flights and flows along their length, transferring the heat conducted through the liner 103 from the walls of the tube flights by forced convection. By regulating the valves 132, the flow of coolant in each tubing flight can be independently regulated so as to compensate for desired changes in cooling rate.

It will be obvious to those skilled in the art that many variations may be made in the embodiments chosen for the purpose of illustrating the present invention without departing from the scope of the invention as defined by the appended claims.

What-is claimed is:

1. A casting wheel including a casting ring defining a peripheral casting groove having side surfaces and an intermediate bottom surface, and a plurality of successive segmented coolant conducting tubes in heat exchange relation with at least one of said surfaces.

2. A casting wheel including a casting ring defining a peripheral casting groove having side surfaces and an intermediate bottom surface and a plurality of successive series of segmented coolant conducting tubes, one tube of each series being in heat exchange relation with one of said surfaces.

3. A casting wheel including a casting ring defining a peripheral casting groove having side surfaces and an intermediate bottom surface, and a plurality of pairs of. successive series of segmented coolant conducting tubes one pair of series being in heat exchange relation with one of said surfaces, each series of tubes of each pair being in staggered relation to one another.

4. A casting wheel including a casting ring having'a liner defining a casting groove in said ring, a series of quadrantal coolant tubes in said ring in contact with said liner; and separate means for supplying coolant to each quadrantof coolant tubes.

5. In a castingwheel, a casting ring having a casting groove defined by side faces and an intermediate bottom face and having a plurality of channels with at least one of said'plurality of channels 'being adjacent each of said side faces and said bottom face, means for feeding coolant under pressure separately and independently into each of' said plurality'of channels, and meansfor control- ;ling the velocity of coolant flow through each of said plurality of channels independently of the velocity of coolant flow through others of said plurality of channels whereby independently variable rates of heat transfer through said side faces and said bottom face from a molten metal in said casting groove to coolant in said plurality of channels are provided.

6. The casting wheel of claim 5 in which said side faces and said bottom face are formed by a relatively thin Walled liner positioned within the peripheral surface of said casting ring and in which at least some of said plurality of channels are positioned immediately adjacent said liner so as to be in direct heat exchange relationship with said liner.

7. The casting wheel. of claim -5 in which said side faces and said bottom face are formed by a relatively thin Walled liner positioned within the peripheral surface of said casting ring and in which at least some of said plurality of channels include tubing positioned within said casting ring to engage said liner.

References Cited by the Examiner UNITED STATES PATENTS 944,370 12/1909 Monnot 22,57.2 2,816,344 12/1957 Pisoni 2257.4 XR

FOREIGN PATENTS 536,3-16 1/1957 Canada. 336,556 4/1959 Switzerland.

I. SPENCER OVERHOLSER, Primary Examiner.

R. S ANNEAR, Assistant Examiner.

Claims (1)

1. A CASTING WHEEL INCLUDING A CASTING RING DEFINING A PERIPHERAL CASTING GROOVE HAVING SIDE SURFACES AND AN INTERMEDIATE BOTTOM SURFACE, AND A PLURALITY OF SUCCESSIVE SEGMENTED COOLANT CONDUCTING TUBES IN HEAT EXCHANGE RELATION WITH AT LEAST ONE OF SAID SURFACES.

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