US2543936A - Apparatus for covering a metallic core with a cast layer of another metal - Google Patents

Description

March 6, 1951 APPARATUS FOR Filed Sept. 22. 1947 J L. REYNOLDS COVERING A METALLIC CORE WITH A CAST LAYER 0F ANOTHER METAL 2 Sheets-Sheet 1 (fig: f,

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March 6, 195] J. L. REYNOLDS 2,543,936

APPARATUS FOR COVERING A METALLIC CORE WITH A CAST LAYER 0F ANOTHER METAL Filed Sept. 22, 1947 2 Sheets-Sheet 2 azm/lm g memo /6 #arm; MD ormmmw Maw/m *9 4 l "I I l I 61 L ,1 I TQM/ w A Q avwowkw Patented Mar. 6, 1951 APPARATUS FOR COVERING A METALLIC CORE WITH A CAST LAYER OF ANOTHER METAL Julian L. Reynolds, Richmond, Va. Application September 22, 1947, Serial No. 775,469 1 Claim. (01. 22-572) This invention relates to an improvement in an apparatus for fabricating metal, and more particularly, to an apparatus for covering a metallic core with a cast layer of anothermetal to produce a composite metallic wire, rod or bar in which the covering layer tenaciously adheres to the core and is smooth and uniform and of controlled thickness.

The present invention finds its major utility in the covering of metallic. cores with aluminum or aluminum alloys. It will be specifically described in connection with the covering of cores of ferrous metal with aluminum or its alloys although it is applicable to other dissimilar metals so long as the metal of the core has a melting p int substantially above that of the covering metal. Certain of the principles of the present invention are also applicable to the covering of a metallic core having a melting point in the same range as the covering metal, the details of the latter process being disclosed in my copending application, Serial No. 778,777 filed October 9, 1947. In the present specification and claims, the term, "iron will be employed as generic to iron and its alloys including steel and the term aluminum will be employed as generic to aluminum and its alloys except where the context shows the contrary to be intended.

Composite structures having an iron core and an aluminum covering are particularly suitable for conductors of electrical currents, for example, for power lines. Aluminum of conductor grade has high electrical conductivity relative to its weight, but in general, has low tensile strength. Composite wires or rods in accordance with the present invention can be produced so as to have high tensile strength by employing a core of iron or other high tensile strength metal. At the same time, the composite structure may have high electrical conductivity since the covering of aluminum or other highly conductive metal may have any desired thickness relative to the core. In addition to imparting high conductivity to the structure, the sheath of cast metal completely covers the core and protects it from corrosion.

Previous attempts to cover ferrous metal or other cores with aluminum have involved passing the core through a bath of molten aluminum and withdrawing the core from the surface of the bath or spraying molten aluminum on the core. By such procedures, the aluminum coating has been restricted to a thin layer not greater than a few thousandths of an inch in thickness and an attempt to increase this thickness has resulted in uneven or lumpy coatings. Even the thin coatings obtained are likely to be uneven z 7 and, in some instances. discontinuous. Composite conductors have, therefore, been usually fabricated by laying strands of aluminum around an iron core, this construction being expensive and failing to protect the core from corrosion.

The present invention enables a continuous covering sheath to be formed around an iron core in a manner which welds the aluminum to the core. Furthermore. the covering sheath may be of substantially any desired thickness, the core is accurately centered and the sheath is uniform in thickness and has a smooth outer surface. This is accomplished by pulling the core through a casting die while delivering molten metal to the entrance end of the die. The entrance end of the die is maintained at a temperature above the melting point of the covering metal and the remainder of the die is cooled. The molten metal is thereby formed into a sheath and solidified in the die so that a continuous composite structure having a solid metallic sheath welded around a metallic core is obtained.

The successful application oi a sheath of aluminum welded to a core, particularly an iron core, requires that the surface of the core entering the casting operation be exceptionally clean and free from oxides and moisture. The invention, therefore, also contemplates cleaning and conditioning steps for the core. In some instances, it is desirable to surface treat the core in order to provide an etched or pitted surface thereon for increasing the bond between the aluminum and the core. In most cases, fluxes are not necessary or desirable, as they tend to contaminate the aluminum or other metal being cast, but in some instances fluxes such as borax or boric acid are advantageously applied to the core entering the casting operation. In general, the core should be rigorously maintained out of contact with the atmosphere, or even be subjected to a reducing gas between the cleaning operation and the casting operation. In general, cores of iron or other metal having a melting point substantially higher than the melting point of the metal being cast should be preheated to a temperature in the same range as the melting point of the covering metal before being introduced into the casting die and the temperature of the molten metal entering the casting die should be just above the melting point of such metal.

For producing composite wire of small diameter, it is frequently desirable to repeatedly draw the original composite bar through reducing dies. The metal of the core as well as that of the sheath is work hardened by drawing and it is usually necessary to anneal between at least some of the auaosc drawing operations. Particularly in the case of an iron core and an aluminum sheath, the annealing temperature of the core is usually above the melting temperature of the sheath. By employing low temperature annealing ferrous alloys for thecore or high melting point aluminum alloys, the annealing temperature of the core can be brought below the melting temperature of the sheath to enable annealing of the entire structure. In this case annealing of the core also takes place in the casting operation to condition the structure for subsequent drawing.

It is therefore an object of the invention to provide an improved apparatus for continuously casting a sheath of metal around a dissimilar metal core to produce a composite wire, rod or Another object of the invention is to provide an improved apparatus for casting a continuous sheath of metal around a core of dissimilar metal to produce a continuous sheath completely covering the core and welded to the core and of any desired thickness.

Another ob ect of the invention is to provide an' improved apparatus for casting a metal sheath around a core of dissimilar metal in which the core is pretreated to provide a firm and tenacious bond between the two metals.

Another object of the invention is to provide an improved apparatus for casting a sheath of aluminum about a core of ferrous metal or other. metal having a substantially higher melting point than the aluminum.

Another object of the invention is to provide an improved apparatus for casting a thick sheath of aluminum about a core of dissimilar metal having a substantially higher melting point than said aluminum to produce a composite structure which can be drawn'to smaller size without rupturing the bond between the aluminum and the metal of the core.

A further object of the invention is to provide an improved apparatus for producing a composite wire, rod or bar having a metallic sheath cast about a metallic core of a higher melting point metal than the metal of the sheath in which the metal of the core as well as that of the sheath may be annealed.

Further objects and advantages of the invention will appear in the followingdescrlption of the preferred embodiments thereof given in connection with' the attached drawings, of which:

Fig. 1 is a diagrammatic vertical section through a continuous sheath casting apparatus:

Fig. 2 is a cross-section taken on the line 2-2 of Fig. 1;

Fig. 3 is a view similar to Fig. 1 showing modification of the casting apparatus;

Fig. 4 is a fragmentary view similar to Fig. 1 showing a further modification for casting a sheath about a plurality of strands forming a core;

Fig. 5 is a fragmentary end elevational view of a portion of the apparatus of Fig. 4;

Fig. 6 is a diagrammatic view similar to a flow sheet showing the pretreatment steps of the pr ss;

Fig. 7 is a view similar to Fig. 6 illustrating a modified process; and

Fig. 8 is another view similar to Fig. 6 illustrating a further modified process.

Referring to Fig. 1, the casting apparatus of the present invention includes a suitable container for molten metal, shown as a pot w, a casting chamber II, a casting die indicated generally at l2, pretreatlng apparatus indicated generally at I2. pulling apparatus shown as pulling rolls l4 and tension rolls I. The pot i0 is adapted to receive molten metal, such as molten aluminum from a ladle or other source. This pot may be provided with heat-insulation (not shown) or heating means (also not shown), as is well known in the art, to prevent solidification of the molten metal. The pot It may have a lower discharge opening I! communicating with a conduit is forming part of the casting chamber Molten metal flows downwardly by gravity from the pot into the casting chamber H and then into the entrance I! of the casting die I2.

The casting die l2 may include a casing 2| having a flange 22 for securing the casing 2| to the casting chamber ll and may have a cylindrical lining 23 of refractory material. While a good grade of cast iron is suitable for the pot l0 and casting chamber II, for most low melting point metals including aluminum, it has been found that the solidifying aluminum or other metal welds to the walls of a metal die. The refractory material thus far found most satisfactory for aluminum is an extremely pure grade of graphite having a small crystal structure. The lining 23 has its outer surface accurately machined to fit the interior of the casing 2| and has its inner bore 24 also accurately machined to substantially a true cylinder. In solidifying, the aluminum shrinks away from the walls of the die to provide clearance for the solid bar or rod. The lining 23 may be replaceable and may be retained in the casing 2| by a shoulder 26 at the entrance end of the casing 2| and an apertured disc 21, suitably secured to the discharge end of the casing 2| and providing a shoulder also engaging the lining 23. The casting chamber H is preferably surrounded by suitable heating means, shown in Fig. 1 as being made up of electrical resistance units 28 embedded in refractory 29. The heat input to the casting chamber II should be controllable so that the metal in the casting chamber may be maintained accurately at a desired temperature, this temperature, in general, being just slightly above the melting point of the metal being cast. The core 30 may enter the casting chamber through a packing gland 3| which aligns the core with the casting die. Accurately aligned tension rolls It may likewise operate in conjunction with the pull rolls ll to hold the core in alignment with the casting die. In many cases, it is desirable to preheat the core entering the casting chamber II and any suitable heating arrangement which will not cause corrosion of the core may be employed. An induction heating coil 32, positioned in a closed chamber 33, has been shown. In general, it is desirable to maintain the core 30 out of contact with the atmosphere after its surface has been thoroughly cleaned. In order to accomplish this, the packing gland 3| is shown as being enclosed in chamber 34 into which an inert gas or reducing gas may be introduced through a pipe 36. This gas may then flow through the heating chamber 33 and into a closed chamber 31 surrounding tension roll l6.

The core 30 is then pulled through the casting die l2, the entrance end of which is preferably surrounded with molten metal in order to maintain the entrance end of the die above the melting point of the metal being cast. It is important that the molten metal entering the casting die remain molten until it is well withanaeae I in the casting die, after which it should be rapidly cooled to a solid state. In order to rapidly cool the molten metal, the major portion of the casting die is preferably brought into direct contact with a cooling medium such as water. Thus, the portion of the casting die exterior of the casting chamber ll may be surrounded by a casing 38 into which any suitable liquid cooling medium, for example, water may be introduced through a pipe 39. The casing 38 may have a restricted discharge opening 4| concentric with the composite member issuing from the casting die so that the casing 38 remains substantially full of liquid cooling medium, this COOIlIlg medium continuously entering through the pipe 39 and being discharged through the opening 4| in contact with the cast metal. A relatively thick flange 22 on the casing 2| is preferably employed to minimize heat exchange between the heated entrance end of the casing and the cooled discharge end. The casing 2| is preferably provided with a plurality of longitudinal slots 42, also shown in Fig. 2, which extend entirely through the casing so that the cooling medium comes into direct contact with the lining 23.

By pulling the composite bar 43 out of the casting die i2 at an appropriate speed, a smooth sheath of metal is continuously cast around the core 30. The core is thus stretched between pull rolls I 4 and tension rolls [6 so that it is accurately positioned in the casting die, the packing gland 3i assisting in maintaining the position of the core 30. It will be noted that the packing gland 3| has its inner member detachably secured to the casting chamber ii so that diiferent sized or different shaped cores may be employed by merely substituting an appropriate packing gland. Furthermore, the external diameter of the sheath cast upon the core can be changed by merely substituting a lining 23'having a difierent internal diameter. While the invention is chiefly concerned with casting a circular sheath around a circular core, it is apparent that cores of any desired shape may be employed with a suitable packing gland therefor and that the interior of the lining 23 of the casting die may likewise have any desired shape.

As shown in Fig. 3, instead of employing a separate casting chamber, the core may be pulled directly through a pot 44 having a packing gland 35 secured to one side thereof and a casting die if secured to the other side thereof. In this case, the molten metal in the lower portion of the pot 44 should be maintained at substantially the desired temperature for casting, that is, a temperature just above the melting point of the metal. Since the casting die i2 is cooled, a supplemental heating means, such as electrical resistance elements 46, may be positioned adjacent the entrance to the casting die in order to maintain the entrance to the casting die surrounded by molten metal and to insure that the metal entering the casting die is in molten condition. Otherwise, the apparatus of Fig. 3 may be entirely the same as the apparatus of Figs. 1 and 2.

The core entering the casting apparatus of Figs. 1 and 3 need not be a solid core. For example, it may be made up of a plurality of strands twisted together. As shown in Fig. 4, it is entirelypossible to cast the molten metal around a plurality of parallel core elements 41. These core elements may pass through tension rolls 48 individual to each of the elements and then through an aligning device 49 which may have a plurality of rolls 5i for aligning the various core elefor example,

ments with apertures 52 in a packing gland 53 having its inner element secured to a casting chamber such as the casting chamber I l of Fig. 1. A five-element core is shown in Figs. 4 and 5, but it is obvious that any desired number of elements or strands may be employed for the core. Since the pulling apparatus, for example, the pulling rolls Id of Fig. 1 and the tension rolls l6 maintain the core or core elements under tension in the casting chamber, even the strands of the multiple-strand core of Figs. 4 and 5 are held in the desired position in the casting die so that these core elements are accurately positioned in the final composite bar.

- While the casting dies of Figs. 1 to 5 are shown as having horizontal axes, it is possible to position a casting die so that it has a vertical axis, with its entrance in the bottom of a pot for the molten metal. ,With such an arrangement, the packing gland can be eliminated and a simple guide for the core substituted. Such a guide, however, should extend below the surface of the pool of molten metal so that the core enters the pool below the surface of the molten metal, and is not contaminated by contact with any film of oxides on the surface of the pool.

Fig. 6 illustrates a series of steps which can be employedin the present invention. In Fig. 6, the core 30 may be passed in succession through a cleaning step 53, a drying step 56 and a heating and deoxidizing step 51 prior to entering the casting chamber I l. The tension rolls 16 are shown as being positioned between the drying step 56 and the heating step 51 since, in general, the core can be passed in a straight line through the heating and deoxidizing step 51. It is, however, entirely possible to position the tension rolls l6 directly in front of the casting chamber ll, as shown in Fig. '7. The cleaning step of Fig. 6 may be substantially any treatment which will remove substantiallyall foreign material from the surface of the wire. Such a cleaning step usually involves passing the core through a cleaning solution which solution may be an alkali such as caustic soda or trisodium phosphate or it may be an acid solution such as sulfuric acid, hydrochloric acid, etc. The nature of the cleaning solution will depend upon the metal of the core as well as the type of impurities found on the core. Oily foreign material generally requires an alkali cleaning while oxidized material frequently requires acid cleaning. A succession of steps involving both acid and alkali cleaning operations are sometimes necessary. The cleaning operatiton-may be entirely chemical or electrochemical methods may be\e mployed, such as using the core as an anode in an electrolyte. If necessary, mechanical operations, such as brushing or scrubbing, may likewise be employed and the cleaning step may be combined with a surface treatment step for giving an etched or pitted surface, as later discussed. Particularly in the case of an iron core, a sodium hydride scale removing process where sodium hydride is the essential ingredient in a molten composition, may be employed. In some cases, it is desirable to leave a small amount of sodium hydride on the core as a flux since this material assists in the bonding of aluminum to iron wire. Other fluxes known to the art, such as borax or boric acid, may alternatively be employed after any of the cleaning operations above discussed and may be applied to the core, for example, by dipping the core in a solution of the flux and then drying. I It is, however, desirable to avoid the use 7 of fluxes if a good bond can be secured in their absence, which is usually the case. It is important that the core be substantially free of moisture when it enters the castin chamber. A drying step of any known or suitable type may be employed, for example, subjecting the core to a stream of heated drying gas which 1 is inert to or has a reducing action on the metal of the core. Such a drying step may usually be combined with a preheating step for the core.

When treating cores having a melting point substantially higher than the melting point of the covering metal, best results are obtained by preheating the core to a temperature approximately the same as that of the molten metal applied to the wire casting step before the core enters the casting chamber. An efiective and simple manner of accomplishing this preheating is by induction heat as indicated by the induction heating coils 32 of Fig. l, but any other controllable heating operation may be employed, such as exposing the core to the heat from electric resistance units, using the core itself as a resistance unit by flowing electric current through the core, or passing the wire adjacent heated refractory surfaces. In general, it is necemary to avoid an oxidizing atmosphere, and best results are obtained by maintaining the core out of contact with the atmosphere from the time that it emerges from the cleaning step. A closed system containing an inert or reducing gas is preferred.

Fig. 7 illustrates a somewhat more elaborate series of steps through which the core may be passed aspiirt of the process for forming a composite bar. In Fig. 7, a drawing Step 58 is indicated in advance of the cleaning step 54. The apparatus for such a drawing step may include a reducing die 59 and pull rolls 6!. In addition to accurately sizing the core before it enters the casting operation, the drawing operation tends to remove or at least craze oxide coatings on the core to render the core more susceptible to cleaning in the cleaning step. Fig. '1 also discloses a second drawing operation 62 having a reducing die 63 and pull rolls 64 after the casting operation to illustrate the fact that the composite structure issuing from the casting operation may be reduced in size by a drawing operation. In general, the composite structure may be drastically drawn in one or a series of drawing operations to reduce both the size of the core and the covering sheath. The sheath tenaciously adheres to the core, and by the method of Fig. 7, fine covered wires can be produced, particularly if the metals of the composite bar enable annealing of the core as well as the sheath, as discussed in more detail below.

Fig. 8 illustrates another series of steps which may be employed particularly when the metal of the sheath is difllcult to weld to the metal of the core. The apparatus of Fig. 8 may involve a sur- 8 clude\electroplating or the treatment of the core with a solution of a metal which is lower in the electromotive force series. 1 Fig. 8 also includes a platingstep 61 which may follow the casting step. In such a step, any desired metal, such as copper o nickel, may be plated on to the sheath by any known or suitable chemical or electroplatingstep. If the plated metal is ductile, the'final composite bar may be drawn in a drawing step 62 to reduce the diameter of the structure.

The above-described cleaning operations, either with or without a surface treating step to produce a surface having minute pores or pits, enables the core to be introduced into the castin apparatus with a surface of virgin metal so that aluminum or other metal cast on the core welds with or alloys with the surface of the core. As stated above, the molten metal is preferably maintained at a temperature just above its melting point. One reason for this is to reduce the amount of cooling of the casting die necessary to solidify the molten metal in the die. In the case of aluminum or the usual aluminum alloys having a melting point range from aproximately 1055" to 1220 F., the temperature of the molten metal may range from approximately 1100 F. to 1300 F. In some cases, where better welding of the covering metal to the core is obtained at a higher temperature, temperatures substantially above the melting point of the metal being cast may be employed in the casting chamber. Molten aluminum has a tendency to rapidly dissolve certain metals includingsome grades of iron or steel as well as copper, even though such metal has a melting point substantially above that of the aluminum. Such dissolving action weakens the core or may produce a relatively thick layer of an alloy between the core and the sheath having undesirable properties. When such conditions are encountered, they may usually be corrected by decreasing the temperature of preheat face treating step 66 positioned between the cleaning step 54 and the drying step 56, Such a surface treating step may include any operation which produces an etched or pitted surface on the core to provide a tooth" for bonding. The treatment may be a chemical or an electrochemical etching operation or a mechanical treatment of the wire, such as scouring, wire brushing, sand blasting, grinding, or other abrading steps. The surface treating step may also involve a plating ste in which a metal which bonds well with aluminum or other metal being cast on a core is first plated on the core. Such a plating step may inof the core or the length of time it remains in the molten metal or both. It may even be necessary to chill the core before it enters the molten metal.

In many cases, the molten metal itself may be relied upon to preheat the core before it enters the casting die and this is particularly true of operations such as illustrated in Fig. 3, where a considerable length of the core is exposed to the molten metal before the core enters the casting die. It will be apparent that in Fig. l, casting chambers of different lengths may be employed in accordance with the nature of the metal of the core and of the metal being cast on the core so as to enable the core to be properly preheated by the molten metal. It is further apparent that the core may be partly preheated before it is introduced into the casting chamber and then further preheated by the molten metal before the core enters the casting die.

When it is desired to pass the composite structure from the casting die through a series of drawing operations. the annealing of the core as well as of the sheath between drawing operations becomes important. In the case of casting aluminum upon an iron core, the usual iron or steel cores have an annealing temperature substantially higher than the melting point of aluminum or aluminum alloys. Some drawing of the temper of the core can usually be obtained by employing temperatures below the melting point of the aluminum, but in general, a satisfactory annealing treatment cannot be obtained. One way of fabricating a composite bar in which an iron core can be annealed is to employ a ferrous alloy Y 9 which has a low annealing temperature. Such alloys are known to the art and examples of two suitable alloys are given below:

Such alloys anneal substantially below the melting point of aluminum which is approximately 1220 F. and below the melting point of most aluminum alloys. With such a low temperature annealing iron core, aluminum of conductor grade can be successfully employed as a covering metal where the resulting composite structure is subjected to a series of drawing operations. An example of conductor grade aluminum is as follows:

Per cent Aluminum 9955-983 Copper .05- .075 Silicon .04- .12 Iron .08- .24

The melting point of compositions in the above ranges varies from approximately 1210" to l220 F.

On the other hand, it is possible to employ standard iron or steel cores which anneal at temperatures substantially above 1220 F. Many metals will increase the melting point of aluminum, among these metals being iron, nickel, chromium, cobalt and tungsten. The proportions of these various metals which may be added to aluminum may vary, but the following percentages may be considered to be working examples:

Per cent Tungsten Iron s Nickel i5 Chromium 2 Cobalt 2 In the proportions given above, each of the metals individually added to aluminum will increase the melting point of the aluminum to a temperature substantially above the annealing temperature of most iron or steel having the requisite tensile strength, drawing properties, etc., suitable for cores of composite wires, rods or bars. It is, of course, apparent that various combinations of the alloying metals listed may be employed but care must be taken to avoid the formation of eutectic mixtures having a lower melting point than desired.

In casting aluminum about a core, the core may be drawn continuously at a uniform rate through the casting die but in many cases, it has been found that superior results are obtained if the core is moved intermittently with rest'periods of short duration between periods of motion of the core. By such intermittent motion of the core through the drawing die, more uniform may be employed. Many types of such pulling apparatus are known to the art. If pulling rolls are employed for the casting operation, these rolls may be either rotated continuously or intermittently by any suitable driving apparatus. Also, tension rolls it have been illustrated throughout the drawings, but it is also obvious that any other known or suitable type of apparatus which resists movement of the core therethrough may be employed.

It will be apparent that the liquid molten metal at the entrance of the casting die is under substantial pressure since the entrance end of the die is a considerable distance below the upper surface of the molten metal. This pressure is ordinarily suflicient to cause the molten metal to flow evenly and uniformly into the entrance end of the casting die. It will be further apparent that the pressure at the entrance end of the casting die may be increased, if necessary, in a particular casting operation by increasing the height of the molten metal above the casting die. This pressure may also be increased by applying pressure to the surface of the body of molten metal, for example, by a pressure plunger pressing against the upper surface of the molten metal or by employing a closed pot for the molten metal and maintaining a body of inert gas under pressur above the molten metal. The process may be operated intermittently, i. e., the pressure in the pot may be released while the pot is recharged with molten metal or the molten metal may be continuously pumped into the pot. It is also possible to employ a pump for the molten metal beween the supply pot and the casting die, for example, a gear or similar type of pump preferably constructed of refractory material or a refractory piston forcing molten metal into the en'- trance oi the casting die.

From the above disclosure, it is apparent that 4 I have provided a simple and rapidly operating apparatus for producing a composite wire, rod or bar by casting a metal sheath around a core. The resulting composite structure has the sheath tenaciously adhered or welded to the core and the sheath is of uniform thickness with the core accurately placed therein and has a smooth uniform surface. The covering sheath may have substantially any desired thickness. For example, the thickness of the sheath may range from a thousandth of an inch to a thickness several times the diameter of the core. Large cores having thick sheaths may be employed to produce wire or rods of small sizes including fine wire by successive drawing operations upon the composite structure.

While I have disclosed the preferred embodiments of my invention, it is understood that the details thereof may be varied within the scope of the following claim. 4

I claim:

Apparatus for casting a metal sheath upon an elongated metal core having a melting point substantially greater than that of the metal sheath, comprising an elongated horizontally disll posed casing divided into a series of chambers by vertical walls centrally apertured to allow the core to pass through the casing, tension rolls within the first chamber at the entrance end of the casing, core heating means disposed witha in the second casing chamber, means for introducing a core protecting gas into the third casing chamber, which gas emerges through the central wall aperture into said second and first chambers while contacting said core, a casting chamber having an axial apertured gland extending into said third casing chamber and having an inlet for the introduction of molten sheath metal, heating means for said casting chamber. a casting mold having an entrance area projected into said casting chamber and having an exit area projected into a fifth casing chamber,

a slotted casing surrounding said exit area or the mold, means for circulating a fluid cooling medium within said fifth casing chamber, and pull rolls acting in opposition to said tension rolls for advancing the core through the casing chambers.

JULIAN L. REYNOLDS.

12 nnraaascas cn'an The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 310,994 Farmer Jan. 20. 1885 443,536 Norman Dec. 30, 1890 910,674 Hancock Jan. 26. 1909 1,508,479 Coats Aug. 5, 1924 1,706,130 Ruder Mar. 19, 1929 1,764,132 Wehr et al. June 17, 1930 2,055,980 Liebmann Sept. 29,-1936 2,072,060 Schultz Feb. 23, 1937 2,091,588 Fiegel Aug. 31, 1937 2,136,394 Poland et a1. Nov. 15. 1938 2,286,759 Patnode June 16, 1942 2,386,119 Jack Oct. 2, 1945 2,438,568

Mann Mar. 30, 1948

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