US3536126A

US3536126A - Casting machine with lightweight casting wheel

Info

Publication number: US3536126A
Application number: US770050A
Authority: US
Inventors: George E Lenaeus; John H Murphy
Original assignee: Southwire Co LLC
Current assignee: Southwire Co LLC
Priority date: 1968-10-23
Filing date: 1968-10-23
Publication date: 1970-10-27
Anticipated expiration: 1987-10-27
Also published as: YU246369A; DE6940858U; DE1966414B2; DE1966414A1; DE1952884A1; DE1966414C3; ES372817A1; FR2024100A1; YU33648B; GB1273590A; FR2024100B1; BE740715A; JPS4823250B1

Description

United States Patent [72] Inventors George E. Lenaeus, Carrollton, and

John H. Murphy, Atlanta, Georgia [21] Appl. No. 770,050 [22] Filed Oct. 23,1968 [45] Patented Oct. 27, 1970 [73] Assignee Southwire Company Carrollton, Georgia a corporation of Georgia [54] CASTING MACHINE WITH LIGHTWEIGHT CASTING WHEEL 14 Claims, 7 Drawing Figs.

[52] U.S.Cl 164/278, 164/273 [51] Int. Cl B22d ll/06 [50] Field of Search 164/87, 273, 278, 283

[56] References Cited UNITED STATES PATENTS 3,321,007 5/1967 Coferet a]. 164/87 3,329,197 7/1967 Cofer 164/87 3,346,038 10/1967 Properzi 164/278 3,411,565 11/1968 Properzi l64/283X 3,464,483 9/1969 Cofer et a1. .v l64/283X FOREIGN PATENTS 668,338 3/1952 Great Britain 164/87 Primary Examiner-J. Spencer Overholser Assistant Examiner-R. Spencer Annear Attorney-Jones and Thomas ABSTRACT: The casting machine disclosed is a casting machine having a casting wheel which is generally U" shaped in transverse cross section, which is mounted on a casting machine by being inserted into an annular channel between two mounting members that engage only the sides of the casting wheel and only with edges that are relatively narrow and that are displaced inwardly from the outer edges of the casting wheel, and which has all of its portions sufficiently thin for the thermal stress in compression induced during casting in the metal from which the casting wheel is formed not to exceed the yield point in compression ofthc metal.

Patented Oct. 27, 1970 3,536,126

Sheet 2 of 3 INVENTORB. George ELLenaeus BYJOhn liMuvphy A TTOR/Vi X5 CASTING MACHINE WITH LIGHTWEIGHT CASTING WHEEL BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the casting of metals and more particularly to a casting machine in which molten metal is cast in a casting mold formed by a peripheral groove in a rotating casting wheel and by a band which closes a length of the groove.

2. Description of the Prior Art The casting of molten metal using a casting machine having a rotating casting wheel with a peripheral groove that is closed by a band to form a casting mold is well-known in the art. Such a casting machine is shown in U.S. Pat. No. 3,279,000 issued on Oct. 18, [966, to D. B. Cofer, et al., for an APPARATUS FOR CONTINUOUS CASTING OF METAL, in U.S. Pat.

No. 3,318,369 issued on May 9, 1967, 116 to T. L. Bray, ct

al., for a COOLING SYSTEM FOR CASTING WHEEL", or in U.S. Pat. No. 3,319,700 issued on May l6, I967 to T. L. Bray, et al., for a RADIAL COOLING SYSTEM FOR CASTING WHEEL.

A characteristic, of a prior art casting machine such as is shown by one of these U.S. patents is that the casting wheel is a rather massive structure which has generally been manufactured by forging and subsequent machining on a large lathe. As a result, the casting wheel in a prior art casting machine of this type causes many problems in the casting ofmolten metal.

For example, the fact that the casting wheel must be manufactured by forgingand subsequent machining makes the cost of manufacturing the casting wheel relatively high and places a practical limitation on the diameter of the casting wheel even though it is known that a large diameter lessens the amount of straightening to which a cast bar is subjected as it leaves the casting wheel. Moreover. the weight of a casting wheel which is a rather massive structure makes the casting wheel difficult to mount upon and remove from a casting machine and generally makes it necessary to use special lifting equipment in order to accomplish the mounting or removing of the casting wheel.

These problems with a casting wheel in regard to the cost of manufacturing and the mounting of the casting wheel upon or removing of the casting wheel from a casting machine are accentuated by still another problem with the casting wheel when the prior art casting machine is used in the casting of a metal such as copper which is cast at a relatively high tern perature. This is because the relatively high temperature of the metal being cast in the casting whccl causes a thermal stress in compression in the metal from which the casting wheel is formed that is greater than the yield point in compression of the metal. As a result, the surface of the peripheral groove in the casting wheel cracks and otherwise deteriorates so rapidly that the useful life of the casting wheel is generally less than ten hours. Thus, the casting wheel must be frequently replaced on a prior art casting machine and the cost of manufacturing the casting wheel and the difficulty with which the casting wheel is mounted upon and removed from the casting machine become even more significant factors in the cost of producing molten metal with the prior art casting machine.

The problem with the casting wheel of a prior art casting machine relating to the cost of manufacturing the casting wheel can be partially alleviated by machining the casting wheel after it has been removed from the casting machine so as to repair the surface of the peripheral groove. However, the peripheral groove of the casting wheel can be repaired by machining only a limited number of times before the structural integrity of the casting wheel is lost by removal of metal or before the entire structure of the casting wheel is damaged by the heat of the molten metal. Moreover, each repairing ofa peripheral groove requires that the casting wheel be removed from and mounted upon the casting machine so that the problem with the casting wheel of a prior art casting machine relating to the difficulty with which the casting wheel is mounted upon and removed from the casting machine is not alleviated by repairing the peripheral groove. 7

An attempt to alleviate the problem with the casting wheel of a prior art casting machine relating to the difficulty with which the casting wheel is mounted upon and removed from a casting machine by providing a removable liner to form the peripheral groove such as that liner disclosed in U.S. Pat. No. 3,31 l,955 issued on Apr. 4, i967, to R. Richards for a DISPOSABLE MOLD MEMBER FOR CASTING MACHIN- E" has been only partially successful. This is because the liner is supported by a support structure which must be relatively massive and which must be manufactured by forging and machining in order to provide the recess in which the liner is positioned. Moreover, the liner and support structure respond almost as a single unit with respect to the inducing of thermal stress by molten metal and as a result the liner deteriorates in use so rapidly that it must be frequently replaced on the casting machine. In addition, because molten metal in the liner must be cooled by colant applied to the support structure or within channels provided by the support structure, both the liner and support structure must be carefully manufactured to insure that the liner fits snugly into the recess in the support structure so as to achieve the proper application of coolant to the liner.

Furthermore, a problem with the casting wheel ofa prior art casting machine which is encountered with or without the use of a liner is that those portions of the casting wheel or support structure which define the sides and bottom of the peripheral groove often have a thickness which is determined in large part by consideration of the structure required to mount the casting wheel or the support structure rather than by consideration of the most efficient cooling of molten metal in the peripheral groove. As a matter of fact. it is the usual thickness ofthcse portions of the casting wheel or the support structure of a prior art casting machine which causes the rapid deterioration of the surface of the peripheral groove that is a significant problem with the casting wheel and which contributes to the other problems considered above.

SUMMARY OF THE INVENTION The invention disclosed here overcomes these and other problems associated with the casting wheel of a prior art casting machine for the casting of molten metal in a peripheral groove in the casting wheel which is closed by a band. This is because the invention provides a casting machine with a casting wheel which has a relatively low cost of manufacturing, which may be of substantially any desired diameter, which is relatively light in weight and otherwise relatively easy to mount upon and remove from a casting machine without the use of special lifting equipment, and which has those portions defining the sides and bottom of the peripheral groove of a thickness that facilitates the cooling of molten metal in the peripheral groove and that retards the deterioration of the surface of the peripheral groove. These improvements in a casting machine are provided by a casting wheel which is generally U" shaped in transverse cross section, which is mounted on a casting machine by being inserted into the annular channel between two mounting members that engage only the sides of the casting wheel and only with edges that are relatively thin and displaced inwardly from the outer edges of the casting wheel, and which has most or all of its portions relatively thin.

Since the casting wheel in the casting machine provided by the invention is substantially a ring which is generally U" shaped in transverse cross section and which requires that no portion be of excessive thickness, a casting wheel having substantially any desired diameter is conveniently manufactured from a metal such as low carbon steel by forming a ring from sheet stock, a channel or the like in a conventional ring forming machine and by welding the abutting ends of the ring together. Moreover, since the casting wheel is mounted on a casting machine by being inserted into an annular channel peripheral groove; V

to be engaged by a flexible metal band, theeasting wheel need I:

not be manufactured as a substantially perfect circle.

' It is because of these manufacturing circumstances that the 5 g casting wheel in the casting machineprovided by theiinven-I tion has a relativelylow. cost of manufacturing and maybe of substantially;.any desireddiame'tei-L It is because of the relativelylight weight of theresulting structure and the mounting of the casting wheel by inserting the castingwheel into an anl nular channel that the castingwheel is relatively easy to mount i I Y 7 I i i i seen from FIG. l that a casting wheel 10 in an embodiment of upon andremove from acastingmachine.

The mounting of the casting wheel by inserting the casting- "wheelinto an annular channel between the edges of two mounting members provides a castingwheel in which those which facilitates cooling of molten metal in the peripheral groove by coolantsprayed on the casting wheel or in a channel defined by the casting wheelanda partition positioned between the mounting members inwardly of the casting wheel.

ll is'be'eause no substantial portion of the easting wheel is of a thickness that results in molten metal ,in' the casting wheel causing a thermalstressin compression in excess of the yield point inycompression of themetal from which the casting wheel is formed that the thicknessof those portions of the, 30 casting wheel which define theperiphcral groove is such'as tok retard the deterioration of the surface of the peripheral groove encountered in the prior art. I

BRIEF DESCRIPTION OF THE DRAW-1N0? a 35 These and other features and advantages of the invention will 'be more clearly understood from the following detailed description and the accompanying. drawing in which like characters of reference designatecorresponding parts '4 throughout and in which:

H6. 1 is a cross-sectional-vie w through a casting wheel I showin'ga first embodiment of the invention disclosed herein;

FIG. 2 is a cross-sectional view through a casting wheel showing a second'embodiment of the invention disclosed' '4-g herein; 7 I a i g 7 FIG. 3 is aphotomicrograph showing a prior art casting wheel at and adjacent the surface of itsperipheral groove following approximately three and one-half hours of casting; and

FIG; 4 isa photomic rograph showing the castingwheelof FIG. 1 at and adjacent the surface of its peripheral groove fol- I lowing approximately three and one-halfhours of casting; J l

-F1G. 5 is'a graph showing the thermal stressin themetal of 1 the castingwheel ofra priorart casting machine, the casting wheel being formed of 510W carbon steeland thermal stress being a function of time following'the pouring of molten copper into the peripheral groove;

F1656 is a graph showing the thermal stress in the metal'of the casting wheel of a prior art casting machine, the casting wheel being formed of copper and thermal stress being a func-. tion of time following the pouring of molten copper intothe 'FIG. 7 is a graph showing th'e thermalstress in the metal of the casting wheel-of alcasting machine embodying the'invention disclosed herein, the casting wheel being formed of low 7 carbon steel and thermal stress being a function of time following the pouringflof molten c'o ppe r into the I. peripheral groove.

DESCRIPTION 0? EMBODIMENTS These l-los. and the following detailed description disclose specific embodiments of the invention. However, it will be understood that the invention may be. embodied in other equivalent forms without departing from the inventive concept.

' i As indicated above, the invention disclosed herein is a casting machine having a castingwheel 10 'which avoids many problems encountered in the prior art. Apart from thecasting wheel 10, the casting machine is substantially as shown by one of the patents listed above in; describing the prior art. Accordingly, only the castin g'wheellfl and related mounting structure are shown in the drawing and described below since the use of the casting wheel 10 on a casting machine and those structural components of a casting machine not shown or described will be understood by those skilled inithe art.

Considering thecasting wheel .10 shown in FIG. 1, it will be the invention disclosedherein is a continuous ring having a casting wheel llldefinesa peripheral groove 11 by opposed walls 12 and 13 and'by a bottom 14. The walls 12 and 13 and bottom 14 cooperate with abandM15' positioned againsty the casting wheel '10-in conventional nanner to form a casting moldM. l I

.ltwill be seen from l'that thegeasting wheel 10 is of substantially uniform thicknessfin' transverse cross section so that the walls 12 and l3"-an d. the. bottom 14 defining the peripheral groove '11 are ofrsubstantially equal thickness. In

addition; it will be seen that the walls 12 and 13 and the bottom 14 are of substantially the same thickness as the band 15. 'lhecasting wheel 10 is mounted on'a casting machine by being inserted into an annular channel 16 provided by a mounting means including an inner mounting member 17 and an; outer mounting member.18:"Theinner mounting member 17' includes an inner angle member 19 which is attached by a.

plurality of bolts such as bolt 20 to an inner ring member'2l. The inner ring member 21 isin turn attached by a plurality of bolts such as bolt22 to eircular mounting plate 23. It will be understood that the circular mounting plate 23 is mounted on a suitable shaft (not shown) for rotation during the casting of molten metal in conventional manner. l v

The outer mounting member 18' includes an outer angle membcr24 which is attached by a plurality of bolts such as bolt 50 to an outer ring member .25.1 The outer ring member 25 ispositionedlaterally relative to thc3i nner ring member 21 by a plurality of positioning members sup as positioning member "26ywhich are. positioned around thieficircumference-of-the inner ring member 21"and e'xtend ibetween the inner, ring member 21 and outer ring inember' -ZiEEach positioning member 26is a shaft127 ex tending through an aperture 51 in the inner ring member 21' and'a' n aperture 29 inthe outer ring member25; X v H 7 That end of the shaft 27 extending through the aperture 51 in the'inner ring member 21jis threaded to receive an inner nut 28 and an outer nut 29 which serve toattach the shaft 27 to the inner ring member2l by engaging oppositesides of the inner ring member 21, Similarly, that end of the shaft 27 extending throughthe aperture 29in the outer'ringmember 25 is threaded to receiveja n in'iier. nut 30 and an outer nut 31 which serve to attach the shaft 27. tothe outer ring member 25 by engaging opposite sides ofthe outer ringmember 25, it will be understood-that positions of the nuts 28, 29,

i 30, and 31 on the shaft 27 p5mpnthe lnni ring member 2l relative to the outer ring member-25. Moreover, it will be unthe outer ring member 25,}the casting wheel 10 is firmly wedged into the annular channel 16 or may simply ffioat in i l the annular channel 16 Hgw everfif 'the casting wheel 10 is I wedged into the annular channel l6,"that portion 32 of the inner angle member .19 which engages the casting wheel 10 is relatively thin and engage s the wall 12 of the casting wheel 10 only in a circle that row gin width relative to the radial width of the wall 12 and that is displaced inwardly from the outer edge 33 of the wall [2. Similarly, that portion 34 of the outer angle member 24 which engages the wall 13 of the casting wheel is relatively thin and engages the wall 13 of the casting wheel 10 in a circle that is narrow relative to the radial width of the wall 13 and that is displaced inwardly from the outer edge 35 ofthe wall 13.

In that embodiment of the invention shown in FIG. 2. the casting wheel 10' is also a continuous ring member having a transverse cross section generally resembling the letter However, in that embodiment of the invention shown in FIG. 2, the casting wheel 10' is not of uniform thickness in transverse cross section and as a result, the walls 12 and 13 adjacent the bottom 14' are of greater thickness than the walls 12' and 13 at the outer edges 33 and 35' Moreover, in the casting wheel 10' shown in FlG. 2. the inner ring member 21' and the outer ring member are positioned relative to each other by a plurality of spacing members such as the spacing member 36 which is similar to a positioning member 26 in that embodiment of the invention shown in FIG. I except that a spacing member 36 does not include outer nuts 29 and 31. The outer sufaces 37 and 38 of the walls 12' and 13' are substantially perpendicular to the bottom 14' so that the walls 12' and 13' must be welded to the angle members 19' and 24 or a plurality of brackets, such as bracket 42 shown in dashed line in FIG. 2. must be mounted on the inner ring member 2l' in order to position the casting wheel 10' in the annular channel 16'. When the casting wheel 10' is welded to the angle members 19 and 24', spacing members such as the spacing member 36 are used simply to maintain the lateral spacing between the ring members 21 and 25'. However, it will be understood that positioning members such as a positioning member 26 can be used with the casting wheel 10" and that the casting wheel 10 shown in FlG. 1 can be welded to the

angle members

19 and 24 so as to increase the rigidity of the casting wheel 10. Moreover, it will be understood that even though the casting wheel l0 is welded to the

angle members

19 and 24'. the portions 32' and 34' ofthC angle members 19' and 24' engaging the casting wheel 10' are relatively thin and engage the casting wheel 10 in circles that are relatively narrow and that are displaced inwardly fromthe

outer edges

33 and 35 ofthe walls 12' and 13'.

From the foregoing description of two embodiments ofthe invention disclosed herein, it will now be understood that a casting wheel 10 or 10' in a casting machine embodying the invention is a continuous ring having a transverse cross section generally resembling the letter U" and which is mounted on a casting machine by being inserted in an annular channel l6 or 16' between two mounting

members

17 and 18 or 17' and'l8' so that it is engaged by only relatively

thin portions

32 and 34 or 32' and 34' in circles that are relatively narrow and that are displaced inwardly from the

outer edges

33 and 35 or 33' and 35 of the

casting wheel

10 or 10. The casting wheel 10 of substantially uniform thickness in transverse cross section shown in FIG. 1 is conveniently manufactured from sheet stock of low carbon steel having a thickness of approximately .12 inches by using a conventional ring forming machine to form a ring and by welding the abutting ,ends of the ring together. Similarly, the casting wheel 10 of varying thickness in transverse cross section shown in FIG. 2 is conveniently manufactured from a conventional three inch ship building channel oflow carbon steel by using a conventional ring forming machine to form a ring and by welding the abutting ends of the ring together.

Thus, a casting wheel 10 or 10' has a relatively low cost of manufacturing and may be of substantially any desired diameter because of the method by which it may be manufactured. Moreover, since a casting wheel 10 or 10' is simply inserted into an

annular channel

16 or 16 and since only the

outer edges

33 and 35 or 33 and 35' are engaged by a band 15, a

casting wheel

10 or 10 need not be a perfect circle and this reduces the cost of manufacturing regardless of method of manufacture.

it will be understood that in a casting wheel 10 manufactured from sheet stock having a thickness of approximately .12 inches, the walls 12 and 13 and bottom 14 have a thickness of approximately .12 inches. Similarly, it will be understood that in a casting wheel 10 manufactured from a three inch ship building channel, the walls 12' and 13 vary in thickness from .25 inches to .5 inches and the bottom 14' has a thickness of approximately .25 inches.

Thus, regardless of the material used in the casting wheel 10 or 10' or the diameter ofthe casting

wheel

10 or 10, a casting wheel 10 or I0 is relatively light in weight compared to the casting wheels of prior art casting machines which have rather massive structures. Moreover, it will be understood that because of this relatively light weight and because the casting wheel 10 or 10' is mounted on casting machine simply by being inserted into a

channel

16 or 16, a casting wheel 10 or 10' is relatively easy to mount upon and remove from a casting machine.

In connection with mounting a casting wheel 10 or 10' on a casting machine or removing a

casting wheel

10 or 10 from a casting machine, it will be further understood that a casting wheel 10 or 10' can be inserted into or removed from a channel l6 or 16' with the angle members l9 and 24 or 19' and 24' being mounted on the casting machine or with the angle members l9 and 24 or 19' and 24 being welded to the casting wheel 10 or 10' so that they are mounted on and removed front the casting machine with the

casting wheel

10 or 10. However, even though the

angle members

19 and 24 or I9 and 24 are welded to the

casting wheel

10 or 10, the casting wheel N) or 10' is still relatively light and can be mounted upon and removed from a casting machine without the use of special lifting equipment.

The absence in a casting wheel 10 or l0 of any portion of excessive thickness not only makes the casting wheel 10 or 10' relatively light but also serves to pro\ ide a casting wheel 10 or 10' which facilitates the cooling ol molten metal in the peripheral groove II or ll. For eutmple. in the casting wheel 10 shown in FIG. 1. the walls 12 and I3 and the bottom 14 may be of substantially the same thickness and material as the band l5 so that cooling around the transverse cross section of molten metal in the peripheral groove ll is substantially uniform. However, in the casting wheel 10' shown in FIG. 2. the walls 12 and 13' vary in thickness so that cooling is related to the mass of molten metal in the peripheral groove ll adjacent each portion ofa wall [2' and [3.

Thus, the walls 12 and [3 or l2 and 13' and bottom 14 or 14' may be substantially of any desired thickness to provide for a desired transfer of heat from molten metal in the peripheral groove ll or H to coolant. In this connection. it will be understood that coolant may be sprayed on the casting wheel 10 or 10' as in the casting machine shown in U.S. Pat. No. 3,279,000 referenced above or may be in a channel 40 such as one formed by a partition 41 between ring members 21' or 25' and which is similar to the channels used in the casting machine shown in U.S. Pat. No. 3,318,369 referenced above.

In addition to facilitating the cooling of molten metal in a peripheral groove 11 or II, relatively thin walls 12 and 13 or 12' and 13 and bottom 14 or 14' in a casting wheel 10 or 10' of a casting machine embodying the invention disclosed herein serve to provide a casting wheel 10 or 10' having a useful life which is longer than that of casting wheels used in prior art casting machines. This is because the relatively

thin walls

12 and 1 3 or 12 and I3 and bottom 14 or 14' retard the deterioration of the surfaces of the walls 12 and 13 or 12' and 13 and the bottom 14 or 14 defining the peripheral groove ll or 11' as is shown by a comparison of HG. 3 with FIG. 4.

F IG. 3 is a photomicrograph of a casting wheel in a prior art casting machine such as that shown in U.S. Pat. No. 3,318,369 showing the surface 43 of the bottom 44 that defines in part the peripheral groove 45 of the casting wheel. The surface 43 is shown as it appears after approximately three and one-half hours of use. FIG. 4 is a photomicrograph of the surface 47 of V manner indicated in FIG. 4.

the bottom l4 that with the walls 12 and I3 defines the t peripheral groove of a casting wheel 10. The surface also shown as it appearsafter approximatelythree and onehalf hours of use. The ca'sting wheel shown in FIG. B and the castingvvheel 10 shown in FIG. 4 were both formed of low carbon steel and the bottom 44 was approximately .5 inches thick. while the bottom l4 was-only approximatelyl2 inches thick v of the wallslZ and I3 or I2 and IS' and of the 14 or 14' is less than thatc'ritical thickness at whichth J stress induced by molten metal in a peripheral groolie II or 11' exceedsthe yield 'point in compressionofthe -nietal from which 'thereasting wheel'ltl or 10' is formed. For each particular metal from which. a casting wheel 10 or l" is formed, the

1. yield point in,compression and thiscritical thickness depend Comparing F IG. 3 and FIG. 4. it will be seen that'the surface 43in the casting wheel of the prior art casting machinelhas deteriorated while the surface'47in the casting wheel 10 is in substantially better condition.

The'reason that the relatively thin walls 12 and 13 or I2 I and I3" andthe relatively thin bottom 14 or 14' retard det'cri oration in a casting wheel 10 orIO' of a surface such as the surface 47 in FIG. -4is shown'by FIGSQS. 6. and7. Fig. 5 is a graph "showing in pounds per square inch the thermal stress incompression at a surface such as the surface 43 of the bottom 44 of the casting wheel of a prior art'casting machine shown in FIG. 3. The casting wheel was formed of low carbon steel and the thermal stress shown in FIG. 5 is a function of time in seconds following the pouring of molten copper into" a peripheral groove such as the peripheral groove 45 shown in FIG.3.'-' I no. 6 is similar to FIG. 5 except that it is for the casting wheel of a prior art casting machineinwhich the casting wheel is formed of copper rather than of low carbon steel, However,

upon the operating conditions of the casting wheel suchas cooling andoth er factors and can be readily determined by one skilled in the art..ln this connectiongit will be understood that the thermal stress in compressionis proportional to the thickness of a wall 12,113,112 or. I3 or bottom 140? 14' and j t that even for a casting wheel or 10'. :formed of low carbon steel. thethicknessof thc wallsl2 andtl3 or: 12 and-I3. and of the'bottoml4 or l4 may generallybe greater than' the approximately .12 inches of the bottom. 14 for which FIG. T

I shows thermal stress andthat certain portions of the wall I2 and 13' mayunder some loperatingcon ditions be relatively thick such as in the casting machineuIO' without excessive deterioration of theperipheral groovel If occurring.

. In connection with the significance of the particular metal from which the casting wheel I0 or-IO. is formed. it is to be noted from FIG. 6 that althoughthetthermal stress in the copper from whichthe casting wheel is formed is less than 30,000 pounds per squareinch, it is nevertheless in excess of I8',000 pounds per square inch which can be regarded as the FIG. 7 is for a casting wheel 10 formed oflow carbon steel and used' in an embodiment of the invention disclosed herein in that the walls 12 and 13 and the bottom I4 are sufficiently thin to-retard deterioration such as that shown by FIG. 3' in the AlthoughFlG. 7shows in pounds per squarcinch thermal stress in compression at a surface such as thcsurfaceflof the bottom 14 in FIG. 4 of a casting wheel 10 which is formed of .low. carbon steel, FIG.f7'is'reprcsentative of any casting wheel 10 or 10' in an embodimentof the invention disclosed herein. In'this connection should be understood that the bottom I4. for which FIG. 7 shows thermal stress'is only approximately .1 2 inches in thickness while the bottom 44 for e which FIGS. 5 and 6 show thermal stress is approximately .5

inches in thickness. H e

, Upon examining FIGS. 5, 6,.and 7 it is seen that'shortly after 1 molten m etal is received in a peripheral groove '11 or 45. the.

thermal stress reaches a maximum value. From FIG. 5 it is 1 the walls 12 and I3 or I2 and I3. and the bottom 14 or 14' seen that when the bottom 44. is of low carbon steel and has a sion is substantially'less than 30,000 pounds per square inch.

Those skilled in'theartwill understand that the yield point in compression for low carbon steel can be considered to be approximately 30,000 pounds per squareinch underccrtain operating conditions of a casting wheel-Thus, inthe casting.

wheel of aprior'art casting machine such as that represented byFIG. 5. the thermal stress incompression inducedin the metal of the casting wheel by molten metal exceeds'the yield.

point in compression of lowcarbon 'steel. while in casting thickness of approximately .5 inches, the maximum value of the thermal stress in compression is well in excessof 30.000 pounds per square inch. From FIG. 7 it isisen that when the bottom 14 is also of low carbon steel but hasa thickness of 'only approximately .12 inches. the thermal stress in compres yield point in compression of copper: under most operating conditions of a casting wheel. However. even when a casting wheel- I0 or 10 is formed of copper there is a critical thickness of the walls I2 and 13 or 12' and I3 and of the bottom I4 or I4 at which thermal stress in compression does not exceed the yield point in compressionL-A.casting wheel I0 or 10' used under the same conditions as the casting .wheel represented by FIG. 6 and having walls 12 and I3 or I2' and I3 and a bottom I4 or I4 will provide an embodiment of the invention disclosed herein if the walls I2 and I3 or 12' and I3" and the bottom I4 or 14' are approximately .30 inches in thickness rather than .50 inches in thickncss as in the casting wheel formed of copper represented by FIG-6. This is because are suflicicntly thin to retard the deterioration. by thermal stress of those surfaces defining a peripheral groove II or I I.

I In connection-with retarding thedeterioration of those surfaces defining a peripheral groove II or .II'. it should be emphasized that in .th'ecasting of molten copper. a casting wheel 10 or I0 of low carbon steel embodying the invention has been found to have a useful life without removal from the casting mechine which isapproximately twice that of a prior t art'casting wheel of low carbon steel. Thus. the advantages of a casting wheel I0. or' I0 as to cost of manufacturing and relative ease of mounting upon or removal frorna casting machine are accentuated by a relatively long useful life.

It will be obvious to those skilled in the art thatmany variations may be made in the embodiments chosen for the purpose of illustrating the pr'esent invention without departing from the scope thereof as defined by the appended claims. t 7

We claim:" h it y I. Ina-casting machine for casting a molten metal in a peripheral groove. a casting wheel having a portion which is formed of a solid metal and ,which on one sidedefiiles a surwheel 10 or 10' from an embodiment .of the invention disclosed herein such as that represented by'FIG. 7,.thefthermal stress in compression is'less than .theyield pointincompression of low carbon steel. As is illustratedtby the line on the,

graph ofFIG, 5, the yielded metal does not return to the zero embodiment of the invention disclosed hereimthe thickness face of said peripheral groove and on another side defines an external surface for the application of a coolant, said portion having a thickness between said one side and said another side which is less than that thickness at whichthe thermal stress in compression induced in said solid metal byheat from a molten metal in said peripheral groove equals the yield point in comis copper.

pression of said solid metal.

2.1 The casting machine of claimjl in which said solid metal "is low carbon steel.

3. The casting machine of claim 4. The casting machine of claim I in'which said casting wheel has a transverse cross section which is substantially U" shaped. e l

1 hi which said solid metal 5. The casting machine of claim 4 including a mounting means for forming an annular channel into which said casting wheel is placed for rotation.

6. The casting machine of claim 5 in which said mounting means includes a first mounting member and a second mounting member and in which said annular channel is defined between an edge of said first mounting member and an edge of said second mounting member.

7. The casting machine of claim 6 in which said casting wheel is engaged only by said edge of said first mounting member and by said edge of said second mounting member.

8. The casting machine of claim 6 in which said edge of said first mounting member engages a radially extending wall of said casting wheel in a circle which is narrow relative to the radial width of said wall and which is displaced inwardly from the outermost edge of said wall.

9. The casting machine of claim 6 in which said casting wheel is wedged into said annular channel.

10. The casting machine of claim 6 in which said casting wheel is welded to said edge of said first mounting member and said edge of said second mounting member.

11. The casting machine of claim 6 including a partition extending between said first mounting member and said second mounting member inwardly of said casting wheel and positioned to define a coolant channel with said casting wheel.

12. The casting machine of claim 4 in which all portions of said casting wheel are of substantially the same thickness in said transverse cross section.

13. The casting machine of claim 4 in which portions of said casting wheel are of varying thickness in said transverse cross section.

'14. The casting machine of claim 4 in which no portion of said casting wheel has a thickness greater than .5 inches in said transverse cross section.