Title of Invention	"A CONTINUOUS CASTING MACHINE"
Abstract	A casting wheel is provided carrying a rotating inner-radius mold wall (8) along its rim and featuring a non-rotating mold sector (11) comprising at least one rigid mold segment (10) incorporating an outer-radius mold wall (12), circumfcrcntially oscillated about an external stationary support (34). The casting wheel includes circumferential guide tracks (5, 6) around the wheel periphery, along which cam guide rollers (15) carrying the non-rotating segments (10) act to maintain a closely controlled interface clearance between the inner (9) and outer-radius (21) mold wall edges throughout Uic rotation. The non-rotating mold sector (11) may be constructed as a single enclosure, or multiple segments (10) hinged togcllicr for oscillation by a single oscillator (32), each segment incorporating its own guide roller system. Each box inside wall doubles as Uic mold envelope outside wall (12) which may be cooled by water sprays (39) directed from nozzles (38) or direct scaling and pressurising of segments (10) through which controlled coolant flow is maintained.. Because of the rigid construction of both wheel and closure, the invention is also adaptable to casting of wide slab sections for flat-rolled products, simply by increasing the width of the wheel in relation to the depth of the mold envelope. The invention includes embodiments providing adjustablc-widlh side dams (44) for adjusting cast slab width, extra clearance for submerged entry nozzles for casting of thin slab sections, and is adaptable for a variety of near net shape products including structural sections. An embodiment includes non-oscillated roller segments (90) carrying a scries of idler rollers (69) in place of the outer-radius mold wall (12), following the formation of a cohesive solid skin on the section being cast. This eliminates significant closure friction and assures non-sliding contact at controlled pressure between slock and wheel, thercby propelling the slock by slalic friction along the are of contact with the wheel, rather than by pulling with withdrawal rollers following discharge, or with driven rollers along the containment scclion. Various features and advantages of the apparatus are disclosed.

Title of Invention

"A CONTINUOUS CASTING MACHINE"

Abstract

A casting wheel is provided carrying a rotating inner-radius mold wall (8) along its rim and featuring a non-rotating mold sector (11) comprising at least one rigid mold segment (10) incorporating an outer-radius mold wall (12), circumfcrcntially oscillated about an external stationary support (34). The casting wheel includes circumferential guide tracks (5, 6) around the wheel periphery, along which cam guide rollers (15) carrying the non-rotating segments (10) act to maintain a closely controlled interface clearance between the inner (9) and outer-radius (21) mold wall edges throughout Uic rotation. The non-rotating mold sector (11) may be constructed as a single enclosure, or multiple segments (10) hinged togcllicr for oscillation by a single oscillator (32), each segment incorporating its own guide roller system. Each box inside wall doubles as Uic mold envelope outside wall (12) which may be cooled by water sprays (39) directed from nozzles (38) or direct scaling and pressurising of segments (10) through which controlled coolant flow is maintained.. Because of the rigid construction of both wheel and closure, the invention is also adaptable to casting of wide slab sections for flat-rolled products, simply by increasing the width of the wheel in relation to the depth of the mold envelope. The invention includes embodiments providing adjustablc-widlh side dams (44) for adjusting cast slab width, extra clearance for submerged entry nozzles for casting of thin slab sections, and is adaptable for a variety of near net shape products including structural sections. An embodiment includes non-oscillated roller segments (90) carrying a scries of idler rollers (69) in place of the outer-radius mold wall (12), following the formation of a cohesive solid skin on the section being cast. This eliminates significant closure friction and assures non-sliding contact at controlled pressure between slock and wheel, thercby propelling the slock by slalic friction along the are of contact with the wheel, rather than by pulling with withdrawal rollers following discharge, or with driven rollers along the containment scclion. Various features and advantages of the apparatus are disclosed.

Full Text	ROTARY WHEEL CASTING MACHINE' The invention relates to the continuous casting of slccl and other mclals and, more particularly, to an improved rolary wheel-type casting machine for continuous casting of billets, blooms, slabs, bars, rods and the like. In the prior art of vertical continuous casting wheels, peripheral closure of the casting mold channel generally is accomplished by cither a moving, endless metal bell pressed against the wheel rim by rollers to realize closure and synchronous peripheral motion with the wheel, or by multiple closure segments, or clamshcll-stylc molds, spaced in abutting sectors around the entire wheel circumference and rotating with it, which arc closed proximate the point of pouring steam entry, and reopened at bar exit from the casting sector during each revolution of the wheel. Known technology also includes n stationary closure bell, pressed in friclional contact against the wheel periphery spanning the casting arc. Disadvantages of the endless bell include: heal from the casting warps the belt, also imparting a wrinkled and warped surface to the cast slock on the belt side of the section; return rollers arc bulky and occupy useful space; a closed and scaled collector and conduit for spent bell-cooling wntcr is difficult, if not impossible, lo realize; bells require a regular schedule of replacement through wear and warpngc; bells do not maintain uniform contact and pressure to hold the casting firmly against Ihc wheel as the casting proceeds arourtd the wheel; and maximum width of cast stock is very limited due lo belt flexure and warpagc. Despite these disadvantages, most commercial production machines employ a moving endless flexible metal belt to effect mold closure. Disadvantages of scgrncnlcd molds include mechanical complexity with inherently very large number of cooperating parts and components; difficulty in maintaining necessary close tolerances between large number of interacting wheel sectors usually 24 or 36, each sector including a clam-shell mold pair, inlet-outlet water piping, mechanical hinging and actuation; problems with metal and slag splashes interfering with mold closure and mold-mold interfaces; and additional tundish pouring clearance necessary to accommodate individual mold sector height above metal meniscus. Disadvantages of the slalic closure arc incidence of slicking between Ihc moving surface of the initially solidified slock and Ihc stationary surface of the closure, resulting in possible skin ruptures and the like; also wear and operating problems associated willi contact friction between wheel perimeter surface and the closure surface. Casting wheels having an oscillating closure have also been proposed. These have not offered practical support of the oscillating casting shoe assembly along with close control of the clearance dimension between channel edge surfaces and the mating edges of the oscillating shoe, or o low-incrtin closure assembly allowing rapid oscillation, in combination with close clearance control. Further, the prior art lacks means for precise positioning of containment rollers relative to the wheel rim, along with control of the containment roller pressure against the cast section below tlic mold, together with capture and disposal of spent coolant, as an integral part of the wheel assembly, rather than of a bulky external structure without coolant capture. Practical means for changing the width of cast slab sections, without changing molds, is also not evident in die prior art of rotary wheel casters. It is a principal object of this invention to provide a rotary wheel continuous casting machine which docs not have the disadvantages cited above for prior art casting wheels. Another object is to provide a casting machine which rcali/.cs a much higher output per strand of equivalent cross-section than do conventional vertical, curved or hori/x)iilal casting machines, and thereby can involve less cost and complexity for equivalent output. A further object is to provide, in various embodiments, a casting machine capable of casting billet and bloom type sections for rolling into rod, bar and tubing sections and, in a modified embodiment, flat slab sections suitable for subsequent rolling into plate, sheet and strip products, with the invention particularly suitable for casting near net shape products such as thin slabs and beam blanks. Varying the width of slab section without changing the wheel channel is a related object. An additional object is to provide a casting machine in which the principal force and pressure propelling the cast section forward is inherently effected at the location of the cross section being cast, rather than by the pulling force and tension created by tlic withdrawal pinch rollers following exit from the casting mold and containment spray chamber area, thus eliminating the main source of skin stresses and tears, with associated substantial increase in casting rale. A still further object is to provide a casting machine capable of casting product with very good surface and internal metallurgical quality. The invention comprises basic features in common with the prior art, namely a rotary wheel continuous casting machine comprising a rotary wheel incorporating a circumferential inner-radius mold wall with two parallel annular inner mold-wall edges, integral to the wheel rim; a non-rotating casting-mold sector (11) comprising at least one rigid mold segment (10), incorporating an outer-radius mold wall having two outer mold-wall edges (21) which arc parallel to, and interface with, said inner mold-wall edges (9), forming a casting mold envelope (43) between said inner (8)and outer-radius (12) mold walls; molten metal pouring means adapted for introducing molten metal proximate the entry end (42) of said mold envelope (43) to pass through in the casting direction of circular wheel rotation and at least partially solidify a cast metal section for exit from the exit end (20) of said mold envelope (43); external support means of said segment (10) adapted to maintain it in a substantially fixed angular position in relation to said wheel; reciprocal oscillation means connected to said segment (10) adapted to effect relative annular oscillation movement of said outer radius mold wall (12) alternately in said casting and reverse directions in relation to said support means and thereby between said outer-radius mold wall (12) and said solidifying cast section jlhc invention comprising combination of these with: at least one annular outer-radius mold-wall edge guide track (5,6) integral to said rotary wheel proximate the wheel rim and which is parallel to said parallel mold-wall edges (9,21); and at least one guide track follower (15) fixed to said non-rotating segment (10) which is maintained in conlacl with said guide track (5,6) during rotation of said wheel, adapted to maintain a substantially constant dimensional clearance between said inner-radius (9) and outer-radius (12) mold-wall edges.) A preferred embodiment includes two of said guide tracks (5,6), one located on cither side of the central plane of rotation of said inner-radius mold wall (8), and at least two of said followers (15) for each of said guide tracks (5,6), and said followers comprise cam roller followers (15) which run in conlacl with said track (5,6) and incorporate means of restraining relative movement in the axial as well as radial direction of said cam roller followers (15) rclalivc lo said track and thereby between said inner (9) and outer (12) mold-wall edges during wheel rotation. The radially guiding surfaces of each said guide track (5,6) typically face radially outwards from the rotation axis of said wheel, and said cam follower rollers (15) ride on Ihcsc surfaces and thereby do nol restrain said casting-mold segments (10) from movement in the radially oulward direction. In one embodiment, the wheel carries another annular balancing guide track (25) with faces directed radially inwards, complementary lo each oulward-facing track (5,6), against which rides al Icasl one balancing cam follower (27) attached lo said non-rotaling casling-mold segment (10) thereby maintaining conlacl between said guide track followers (15) and said guide track (5,6) by radially restraining movement of said casting mold segment (10) in the direction radially outwards from said wheel. In another embodiment, the casting mold segments (10) also carry a supplementary guide track (115) against which fluid-pressure loaded balancing cam followers (114) maintain continuous pressure and conlacl of the guide track followers (15) against the wheel rim, with the balancing followers (114), in turn, being supported and positioned from a fixed support of me machine housing, or the like. The supplementary Irack preferably includes a reverse capturing flange (116) for the balancing follower, enabling the casting segments to be lifted off the wheel and held in suspension during inspection or maintenance. Mold segments (10) most suitably comprises a rigid, semicircular enclosure having two box side walls (13), a box outer cover wall (143) and a box inner wall carrying said outer-radius mold wall (12) on its face, in which said external support means and said oscillation means arc attached to the segment (10), thereby being adapted to oscillate said outer-radius mold wall (12) back and forth in the circumferential direction about a substantially fixed angular location on the casting wheel periphery. Spray nox/lcs (38) arc suitably contained within said enclosure directed radially inwards, to spray coolant directly against said outer-radius mold walls (12) and spent coolant is confined within the enclosure and discharged via an appropriate outlet duct (40). Alternatively, the enclosure may form a prcssuri/cd water jacket, internally baffled to provide an annulus for flow of prcssuri/cd coolant against the outside of mold-wall (12). Appropriately, there arc four studded cam roller track followers (15), with two mounted to project outwardly from each box side wall (13) of segment (10), and two balancing cam roller assemblies, one mounted on the outside of each side wall (13) of segment (10) intermediate between said track followers (15), including means for applying a continuous controlled pressure of the balancing rollers (27) against die tracks (25), sufficient to maintain the guide track followers (15) in continuous contact with the outward-facing guide tracks (5,6). Another aspect of the invention provides a containment-roller sector (28) adjoining the mold envelope exit end (20), similar to the casting mold sector (11) but carrying transverse containment idler rollers (69) journallcd in bearings (72) supported by the segment side walls (13), with faces positioned and adapted to press radially inwards against the outer face of the section being cast to maintain the inner face of the section pressed against the inner-radius mold wall (8), the tangential component of this pressure acting to exert a circumferential forward propelling force on the section in the casting direction. Means arc provided for controlling the radial movement and pressure of these rollers (69) against the face of the section being cast. Other aspects of me invention include apparatus for positioning of movable side-dam bars (44) adapted for varying the width of the metal section being cast; a tangential departure (67) of the outer mold-wall at the entry end (42) of the mold envelope to provide improved access for introducing liquid metal; a mold closure guiding arrangement applicable to spray-cooled solid-block copper casting wheel mold rings (93); and a universal hinge coupling assembly (120) connecting adjoining segments (10, 90) which allows each individual to track independently on the wheel rim, without coupling backlash.Various oilier objects, features and advantages of the process and apparatus of this invention will become apparent from the following detailed description and claims, and by referring to the accompanying drawings, in which: Accordingly the present invention relates to a continuous casting machine comprising a rotary wheel incorporating a circumferential inner-radius mold wall (8) with two parallel annular inner mold-wall edges (9), integral with tile wheel rimJ a non-rotating casting-mold sector (II) comprising at least one rigid mold segment (10) incorporating an outer-radius mold wall (12) having two outer mold-wall edges (21) which are parallel to, and interface with, said inner mold-wall edges (9), forming a casting mold envelope (43) between said-inner (8) and outer radius (12) mold walls! molten metal pouring means for introducing molten metal proximate the entry end (42) of said mold envelope (43) to pass through in the casting direction of circular wheel rotation and partially solidify a cast metal section for exit from the exit end (20) of said mold envelope (43) ! external support means of said segment (10) to maintain it in a fixed angular position in relation to said wheel; reciprocal oscillation means connected to said segment (10) to effect relative annular oscillation movement of said outer radius mold wall (12) alternately in said casting arid reverse directions in relation to said support means and thereby between said outer-radius mold wall (12) and said solidifying cast metal section, in-combination witlv at least one annular outer-radius mold-wall edge guide track (5,6) integral with said rotary wheel proximate the wheel rim and which is parallel to said parallel mold-wall edges (9,21); and at least one guide track follower (15) fixed to said segment (10) in contact with said guide track (5,6) during rotation of said wheel, to maintain a constant dimensional clearance between said inner-radius (9) and outer-radius (21) mold- wall edges. Fig. 1 is an illustrative side view of a rotary wheel casting machine embodiment according to die invention, including a wheel sector illustrated in section, along the plane of rotation intersecting the mold center line; Fig. 2 is a section view along plane 2-2 of Fig. 1 incorporating a mold cavity of general shape suitable for the casting of blooms, billets, bars and rods applicable to production of long products; Fig. 3 is a section view along plane 3-3 of Fig. 1; Fig. 4 is a side view of the apparatus illustrated in Fig. 3; and Fig. 5 is a corresponding section view to that illustrated in Fig. 2 incorporating a mold cavity of general shape suitable for casting slabs, plates, sheets mid strip, as applicable to the production of flat-rolled products; Fig. 6 is a partial front elevation view of a mold-width adjustment mechanism adapted for casting various flat-rolled product widths without changing the wheel mold; Fig. 7 is a sectional view along plane 7-7 of Fig. 6; Fig. 8 is an illustrative partial sectional view of an alternative embodiment substituting containment idler rollers in place of the outer mold wall in the lower portion of the non-rotating casting sector; Fig. 9 is a partial lop view along plane 9-9 of Fig. 8 Figs. 10, ajid 11 illustrate two variations for containment idler roller bearing support, positioning and pressure application; Fig. 12 is a corresponding section view of that illustrated in Figs. 2 and 5, incorporating a mold cavity adapted for the near net shape casting of structural sections and the like; Fig. 13 is a split cross-section illustration of a containment roller segment embodiment; Fig. 14 is a partial side view of the roller segment of Fig. 13; Fig. 15 is a side elevation view of an entry mold scgmcnl assembly; Fig. 16 is a section view along plane 16-16 of Fig. 15; Fig. 17A is a section view along plane 17A of Fig. 15; Fig. 17B is a section view along plane 17B of Fig. 15; Fig. 18 is a section view along plane 18-18 of Fig. 16; Fig. 19 is a side elevation general arrangement view of an embodiment incorporating mold and roller segment balancing devices supported directly from the fixed machine frame; Figs. 20, 21 and 22 illustrate details of the externally supported balancing assemblies as shown in Fig. 19; Fig. 23 is a section view of a suitable segment oscillator assembly; Fig. 24 is a section view along plane 24-24 of Fig. 23; Fig. 25 is a side elevation view of a containment roller segment embodiment, Fig. 26 is a section view along plane 26-26 of Fig. 25; Fig. 27 is a section view along plane 27-27 of Fig. 25; Fig. 28 is a section view along plane 28-28 of Fig. 25; and Fig. 29 is a section view along plane 29-29 of Fig. 27. Referring to the drawings, wheel hub assembly 1, is journallcd upon bearings mounted on fixed supports and the rotated by an appropriate electro-mechanical or hydraulic drive unit, preferably at variable and controlled speed. In the embodiment illustrated, the rotary wheel structure comprises o solid-disc body 2 with radial sliffcncr ribs 19 spanning between hub 1 and U-shaped wheel rim 24, also defining cooling water jacket annulus 4. A typical wheel sue would be 2-4 meters in diameter, although a wide range of sizes arc possible. It is to be appreciated that a substantial part of the drawings arc diagrammatic only, particularly regarding aspects known in the art. Wheel mold cooling water is introduced, and spent water discharged, via appropriate rotary union assemblies incorporated into hut) assembly 1, supplied to and returned from wheel rim 24 via appropriate wheel mounted water pipes 35. The details of tins aspect and numerous other features of the wheel casting machine ore not shown or described herein, being well known in the art, and with many known and obvious options as to selection and configuration available. Casting wheel rim 24 carries annular inner radius mold-wall support rings 3 and also two outer-radius mold-wall edge guide tracks 5, 6 comprising cylindrical radial surfaces, directed radially outward, one on cither side of axial central plane of rotation 7 of the inner radius mold wall, in the embodiment illustrated. The inner radius mold-wall 8 may also include side faces 18 extending radially outwards, as in the embodiment illustrated for casting of a square cross section, approximately at right angles to the inside face of mold wall 8. The mold wall usually of copper or copper alloy, is fastened to support rings 3 such as by screws spaced around the wheel rim periphery. On most casting wheels, side faces 18 arc tapered to diverge transversely outwards, for example, at a slope of 1 or 2 per cent, thereby assuring clearance for tangential discharge of the cast metal section at exit 20, without edge friction or binding between the section and side faces 18. Non-rotating casting mold sector 11 incorporates outer radius mold-wall 12 as its inner face thereby forming a casting mold envelope 43 between said inner 8 and outer 12 mold walls. Sector 11 may comprise a single rigid circumferential mold segment or be made up in multiple mold segments 10. In Uic embodiment illustrated, sector 11 comprises three rigid semicircular mold segments 10 having the abutting ends of segment side walls 13 interleaved and connected together by hinge pins 14. Each segment 10, in turn, lias four cam truck followers 15 mounted on side walls 13 as two opposite pairs, positioned to run in contact with guide tracks 5,6. Appropriately, the roller mounting studs incorporate eccentric bushings 16, lo enable easy adjustment of the clearance 17 between the interfacing inner 9, and outer 21, parallel annular mold-wall edges. Adjustment of these clearances, in the embodiment illustrated, may be effected manually using an Allen wrench applied to a hexagonal socket in the stud end of cam roller 15, whilst measuring the clearances with feeler gauges. Clearances down lo Uic 25 micron area can be accomplished without any contact across the interface, thus emulating a continuous mold wall whilst avoiding wear and galling of these mating surfaces. At typical casting temperatures approaching the liquidus, the combined parameters of surface tension, viscosity and transient solidification in the presence of cold, high-conductivity mold wall material, generally then preclude entry of metal between the mold-edge faces proximate the meniscus. The rollers 15 arc also provided with flanges 22 lo ride against circumferential transverse alignment guide surfaces 23, incorporated into guide tracks 5,6 to maintain transverse (sidc-to-sidc) outer mold-wall alignment. Segment-mounted radially-slidablc brackets, or llic like, of course may be employed lo augment, or as alternatives lo, the eccentric bushings 16 for adjustment of track follower position and thereby clearance 17. Oulcr-radius mold wall 12 may be transversely contoured, for example, recessed between the edges to provide a rounded billcl corner and eliminate the sharp right-angled comer at 17 characteristic of a flat plate shoe, a source of possible rolling mill difficulty. In order to hold each mold segment 10 in place and assure continuous contact of cam rollers 15 will) guide tracks 5, 6 during the course of rotation and application of pressure from Uic section being cast, the inner mold-wall support rings 3 also include a second set of annular balancing guide tracks 25 directed radially inwards, against which ride balancing cam followers 27. In the embodiment illustrated, there is one set comprising two of these rollers 27 applied lo each hinged mold segment 10, cacli set counteracting llic corresponding two sets of rollers 15, leveraged to apply approximately equal force lo each set. The rollers 27 arc mounted on balancing slide arm 29, guided for movement in Uic radial direction only within support ring side bracket 30, and stroked by balancing cylinder 31. Such balancing actuators can be powered by any approprialc fluid, bul compressible gases such us air have a clear advantage when in a pressure-control mode of this application, by compensating for wheel and track eccentricity and irregularity displacements wiUioul use of supplementary proportional or servo control valves or Uic like to meter fluids back and forth. Oscillation of segment 10 along Uic paUi defined by cam rollers 15 along tracks 5,6 is effected, such as by hydraulic oscillator 32 acting between rolalablc bracket 33 fixed lo segment 10 and externally fixed support bracket 34. A wide range of forms of hydraulic and electro-mechanical oscillators as well as casling control systems, arc known in the art of continuous casting. The inner mold walls arc appropriately force water-cooled with water supplied and returned via at least one set of wheel-mounted water pipes 35. Each segment 10 is supplied with coolant, usually water, via an inlet through box side walls 13 or outer cover wall 143 into enclosed hcndcr pipe 37 feeding coolant spray noz/lcs 38 which direct the coolant spray 39 to impinge on the exterior surface of outer radius mold-wall 12. Spent coolant flows by gravity through outlets 40 into appropriate hosing to a sump or the like, usually for rccirculalion. Ease of coolant enclosure, as compared to flexible belt casters, is also to be noted. Removable cover plates 41 incorporated into segments 10 provide access to the sprays for maintenance and the like, as well as rotation adjustment of cam roller eccentric bushings 16. These preferably include quick-release fasteners and seals. Start-up and operation arc conducted in essentially the same manner as a conventional flexible-bell machine, molten metal being poured from tundish 36 into the entry end 42 of mold envelope 43 and the cast metal section withdrawn from the exit end 20 by means of powered withdrawal rolls 26, details omitted as well-known. Fig. 5 illustrates an embodiment adapted for casting of thin slab products. Except for the shape and si/c of the mold envelope, it will be seen that the basic machine features arc essentially the same as those for casting billets and blooms, as illustrated by Figs. 2 and 3. Figs. 6 and 7 illustrate a supplementary apparatus to facilitate the casting of various slab widths without major equipment modifications or substitutions. Rather than confinement of the cast section between side faces 18 of the inner radius mold wall 8, the side faces 89 of partially solidified thin slab 61 arc confined between the two movable mold side-dam bars 44, also fabricated and machined on an arc to a clearance fit between inner 8 and outer 12 mold wall faces. Bars 44 arc confined transversely between side alignment brackets 47 of movable carriage 46, and circumfcrcntially by the interaction between pin 50, as fixed to carriage 46 by bracket 48, and mold side-dam oscillator bracket 49. Carriage 46 is carried on two pairs of vcc-guidc rollers 53 which run on transverse guide track 51, providing linear guided movement only in the transverse direction. Track 51, in turn, is fastened to track support bracket 52 attached to segment 10, and thereby transmits the corresponding circumferential oscillation movement of the outer mold wall to mold side-dam bars 44. Rollers 53 arc preferably mounted on eccentric bushings 62, providing for easy and accurate adjustment of alignment and clearance with guide track 51. By providing a close fit between side brackets 47 and bar 44, these bushings also facilitate precise adjustment of the transverse slope of bars 44. Carriages 46 arc fixed transversely by threaded take-up nuts 59 riding on support bracket 60, variably positioned axially by rotation of opposite-hand threaded carriage drive screws 58, as driven by centrally located hydraulic traverse motor 54. As illustrated, this is a hollow-shaft motor mounted on splined drive shaft 64, as carried between flange bearings 56 of motor support bracket 55, in turn fixed to the outer wall of box enclosure 10. Torque couple-arms 66 act against torque pins 63 to prevent motor body rotation. Shaft 64, in turn, is connected at cither end to drive screws 58 by couplings 57. Mold side-dam bar 44 appropriately comprises a rectangular lube of copper alloy, blanked off at both ends, with coolant provided via flexible hoses connected into coolant inlet and outlet connections 45, one of which is internally piped to the bottom extremity of side-dam bar 44. The faces of bar 44 may also be drilled for lubricant ducts and outlets, to provide face lubrication, such as by rapcsccd oil during operation. During casting, it is well known that the stock cross-section progressively shrinks with cooling and solidification during its descent within the mold, and also that the outer layer of "skin" of the casting is effectively self-scaling once a continuous surface has been formed around the casting perimeter, unless stresses arc present sufficient to create a rupture and associated "break-out" of molten metal. In conventional oscillating mold casters, substantially all of the withdrawal force is usually applied following discharge from a roller spray chamber, or as assisted by a selected few driven rollers within the spray chamber containment area. The forces arc thus applied at a remote point from the solidifying section at mold exit, or a limited number of selected points along the casting length, relying on bar skin tension/compression strength between these points to maintain casting integrity. Because of the stresses this creates, a relatively thick fro/cn skin is necessary at mold exit, substantially limiting the maximum casting speed, to allow sufficient time for formation of this skin. Within the mold envelope, a taper can be added to the outer-radius mold walls 12 by graduating the portion of the face of outer-radius mold walls 12 within sides 18. In addition, Fig. 8 shows a variation including a containment roller wheel sector 28 incorporating containment roller segments 90 which carry containment idler rollers 69, in place of outer radius mold-wall 12, with coolant sprays 39 thereby impinging directly upon the surface of the cast metal section. Along the arc of wheel sector 28, the withdrawal forces can then be applied directly by the rollers 69 at the cross section being cast, by mninlaining static friclional contact and pressure between the stock skin surface and the inner radius mold walls 8, as they move and propel the casting along al essentially identical surface speed. Tcnsional casting slrcss is thereby nearly eliminated, allowing a very substantial increase in practical casting speed for similar effective mold lengths. Since the casting wheel rotation is furnishing the propulsive force, the powered withdrawal rollers 26 arc also usually superfluous. For casting wide slab sections, rollers 69 may also be split into multiple lengths incorporating intermediate segment-supported bearings. It is obvious thai minor leakage of spent cooling water can lake place via clearances 17, in the absence of scaled contact between side walls 13 and inner mold-wall edges 9. A supplementary seal may be added lo minimize tliis leakage (not illustrated). Suitable practice could provide on the order of o meter of wheel arc, e.g. one box enclosure 10 at the top, ns illustrated, incorporating outer mold walls 12 and the two bottom segments 90 be equipped with rollers 69. It will also be obvious that only the lop sector 11 need be oscillated, as an option. One or more of ihc conlainmcnl rollers 69 may also be applied lo cffccl thickness reduction of llic casl metal section by increasing Uic roller pressure, optionally including liquid core reduction when the scclion is only partially solidified. These rollers may be undrivcn idlers or, alternatively, powered so as lo rolalc Ihc roller surface at a rale synchronized with Uic surface speed of Ihc casl mclal section. For starling of casling, a starter block or starter bar is usually inserted into Ihc mold cavily, designed lo move in unison with the wheel once casting commences. When Ihc block can be confined between the wheel rim and conlainmcnl rollers, only a relatively short slarlcr bar is required or, allcrnalivcly, a shorl starter block head having a longer, flexible elastomer bar attached, which can be hollow and contoured lo fit snugly in Uic wheel groove, in order to assisl with scclion guidance following cxil from the machine. The block characteristically includes a protruding top hook or claw designed lo hold the starter block and freshly casl metal together in one piece until llicy arc separated following exit. One praclical difficulty in Uic casling of thin slab product is Uic desired narrow slab thickness in relation to Uic dimensions of submerged-entry nozzles. Figs. 8 and 9 illustrate means to miligalc Uiis problem by a funnel-shaped departure on only Uic oulcr-radius mold wall at Uic nozzle 65, wherein wall 12 is extended vertically and langcnlially upwards, as at 67, al right angles lo Uic wheel horizonlal center line 80 in Uic plane of rotalion of Uic wheel, al Uic Iransvcrsc location of submerged entry nozzle 65, on cither side of which mold-wall 12 is graduated into the slraighl-sidcd cylindrical wall, in Uic form of a half funnel-segment 68 wiUi maximum widUi al Uic location of molten metal entry 42. In Uic embodiment illustrated, where Uic Uiickncss of nozzle 65 is nearly equal lo Uic casling thickness, it may be seen Uiat adcqualc insertion is oblaincd, including good wall clearance, by vcrlical insertion of nozzle 65 parallel lo this vcrlical funnel wall. Fig. 10 illustrates simple means of maintaining position and controlled pressure of Iransvcrsc conlainmcnl rollers 69 against Uic outer scclion surface. The roller shafts 71 arc journnllcd within scaled cartridge bearings 72, riding in guided chocks 73, as recessed in Uic structure of side-walls 13 of segment 90. The chocks 73 and thereby rollers 69 arc loaded and rclraclcd by air or hydraulic cylinders 70, through which the position or force of each roller against the cast metal section surface 104 can be adjusted. Fig. 11 illustrates another means of supporting and controlling rollers 69, whereby the outer race of bearings 72, mounted on roll shaft 83, arc carried within an eccentric bushing 76. Rotating means for bushing 76, such as a pivotally mounted cylinder or rotary actuator (not shown) actuating lever arm 77 of the bushing, can effect both controlled pressure and controlled position of roller 69. Cooling water can also be supplied via rotary union 78 through internal ducting within shaft 83 to roll water cooling annul us 79. The bearings 72 can also be located outside of wall 13 in other embodiments, such as by extension of shafts 71, 83 shown in Fig. 10 or Fig. 11. Fig. 12 illustrates an embodiment in which the mold envelope is in the form of a near net shape structural beam blank. It will be evident that a variety of such mold shapes and sixes can be applied as variations on the basic features of the apparatus of the invention. Figs. 13 and 14 illustrate a containment roller segment variation, in conjunction with a wheel in which a spray-cooled copper block mold ring 93 comprises the wheel rim, combining the functions of inner mold wall 8 and annular outer radius mold wall edge guide track 6. Cam roller track followers 15 ride directly on the mold rim, (guide track 5,6) with flanges 22 riding against bevelled edge surface 94 of mold ring 93. Balancing rollers in this case may more conveniently be mounted to act between the roller segment and a fixed support attached to the machine base, backing frame or the like, rather than the rotating wheel. Mold ring 93 is appropriately cooled by means of inside coolant sprays 159 and side sprays 160. Roll shaft 84 is fixed, except for rotation together with externally eccentric bushings 85 keyed or otherwise fixed to shaft 84, and also concentrically supports the inner race of bearing cartridge 72 carrying roller 69 on Ihc outer races. Pneumatic or hydraulic cylinders 91 function similarly to rotary actuators by stroking eccentric lever arm 92 to control position and pressure of containment rollers 95 against the outer surface 104 of the solidifying cast metal section. This arrangement facilitates close control of Uic face position of roller 69 in relation to surface 104, such as by precise positioning of cylinder 91, for example, employing position sensors for the rod of a hydraulically operated cylinder, including a transducer to accomplish remote electronic automatic position control, to maintain set-point positions. In a case where roller pressure control only is deemed required, the rollers could be directly and individually supported with reference to the machine base or backing plate only, eliminating rollers 15,22 and allowing radial roller position to follow Uic variations in position of casting surface 104 as Die wheel rotates, cylinder 91 being operated pneumatically. Lever arms 92 of adjacent rollers may also be linked together providing for actuation of two or more rollers 69 with one cylinder, but with the potential disadvantage of unequal roller pressures or stock-lo-rollcr clearances occurring. In order to allow adjustable roll positioning, in combination with a full retraction away from the wheel for maintenance and the like, a three-position duplex cylinder or equivalent could be employed in place of single cylinder 91. Figs. 15, 16, 17A& 170 and 18 illustrate additional or alternative embodiments of the mold segment apparatus 10. This includes a prcssuri/cd water-filled inlet chamber 106 separated from outlet chamber 107 by dividing wall 108, incorporating baffle plate 109, as held in position by draw-bolts 110, to assure high-velocity water flow within annulus 111 for cooling of outer radius mold wall shoe 112. Draw-bolls 110 arc scaled by way of an appropriate 0-ring gland 113. The oulcr radius mold wall shoes 112 arc scaled by an claslonicr-coalcd metal gasket 130 and fastened in position by screws 131. Among oilier features illustrated is a cental mold overflow channel 149 at mold entry, to reduce the risk of molten metal jamming the entry junction between wheel and outer mold wall, should overflow conditions occur during casting. The balancing assembly is based upon on external support frame, to locale and control the force of flanged rollers 114 against balancing track 115. Rollers 114, in turn, ore mounted with clearance but captured within retention flange 116, thus providing for retracting the segments radially outward and oil" the wheel lo hold them in essentially fixed position when desired for mold inspection, maintenance, changing of wheels and the like. This segment embodiment includes substantial radial adjustment of track followers 15, in view of the much lower cost of re-machining used oulcr radius mold wall shoes I 12 after use; in comparison with replacement with new ones. Adjusting screw 122 effects adjustment of pillow blocks 121, lobe held in position by locking screws 123. In order lo avoid potential axial segment yawing and vibration, one of the followers 15 of each opposing pair is spring-preloaded transversely by way of compression spring 124 acting between cap 125 and the face of linear bushing 126, thus maintaining continuous running conlacl bclwccn flanges 22 and inner mold edges 94. Side-guide follower rollers, having one of each pair spring or fluid pre-loaded is a more elaborate alternative not illustrated. A single universal hinge-coupling assembly 120 connects adjacent segments together, comprising opposed spherical plain thrust bearings 117, thrusting against end flanges 82 of segments 90 confined by bolt-and-nul assembly 118 and at an adjustable distance of separation bclwccn flanges 82, and also incorporating pre-load spring 119 with spring rale force sufficicnl lo eliminate clearances and any backlash, whilst allowing both Iransvcrsc and angular misalignment bclwccn segments. As applied to mold segments 10, in order to accommodate mold shoe thermal expansion in Ihc cvcnl Lhal adjacent mold shoe ends arc closely bulled together at slart-up, Belleville spring-washers arc appropriately inserted bclwccn Ihc nuls and bearings 117, designed lo balance Ihc opposing force of spring 119, and wilh additional travel sufficient lo accommodate the expansion aflcr slarl-up. Fig. 1713 also illustrates the variation of a contoured transverse profile of outer-radius mold wall 12 in which side faces 18 arc extended past clearance 17 into a recess of outer mold wall shoe 112. This eliminates the aculc angle at the section corner cnlcring into gap 17 and also allows a rounded corner 127 of the cast metal section. As otherwise illustrated to be flat, any metal flash into clearance 17 between shoe and wheel occurs at the section corner, rendering it difficult to hot roll or extrude without introducing lap surface defects or the like, whereby wheel-and-band casters usually mill off the corner flash prior to hot working. Contouring of the outer mold shoe face also extends the range of shapes and sizes which can be cast. Flexible bond closure casting wheels commonly used for casting copper and aluminum billets and rods normally utilizc a much larger sector of the wheel than those for steel, that is, most commonly, entry is at 1-2 o'clock and exit at 9-10 o'clock position, rather than 3 and 6 o'clock. Fig. 19 illustrates the invention as applied to such a wheel, and with segment balancing effected by an air cylinder 145 mounted within a square lube 146, the extension of which carries the segment balancing rollers 114, and guided by sliding bearing pads 144 riding against the inner walls of another square lube 147 fixed to machine frame 148. Oscillator crank arm 99 transmits oscillating motion to mold segments 10, as generated by oscillator drive assembly 156, which is also supported by fixed machine frame 148. Figs. 20, 21 and 22 illustrate details of the segment balancing units as appropriately cantilcvcrcd out from a backing frame also supporting the main casting wheel hub and bearings. Please note that piping and wiring and the like is omillcd from Figs. 15-22 for clarity. Fast casting speeds require rapid mold closure oscillation, towards maintaining sufficient negative strip with minimal surface oscillation marks. Figs. 23 and 24 illustrate a suitable oscillator, in which housing 95 carries bearings 96 for rotation of drive shaft 97 by means of adjustable speed hydraulic molor 98 as an alternative to air motor 74 with gear box and bell drive 75, as illustrated in Fig. 19. Eccentric crank extension 99 revolves around the center axis of shaft 97 carrying connecting rod drive bearing 105. In order to adjust the stroke length as indicated by the graduated index 155, location ring 154 of cantilcvcrcd stub shafl 150 is rotated by nut 151 and locked at the desired stroke length by bolted locking plate 152. Crank 99 may be connected directly to mold segment wrist pin 153. Thus, a sinusoidal reciprocating oscillation, of selected adjustable stroke length, is transmitted to Hie mold segments. Figs. 25, 26, 27, 28 and 29 illuslralc additional or alternative embodiments of the roller segment apparatus 90. The roller eccentric assembly comprises drive eccentric disk 137 and driven eccentric disk 138 which arc equally eccentric to roller shaft 84 and keyed to it by parallel cross keys 134 and 135, as fixed by dowels 136, thus comprising a rigid assembly to maintain parallel rotation of the shaft 84 axis about the axis of disks 137, 138. Containment idler roller 69, as supported by bearings 72, is then rolalablc about shaft 84 by frictional contact with the moving face of the cast metal section. Concentric disks 137, 138 rotate within concentric bushings 161 mounted within axially aligned circular apertures in opposite box side walls 13, and the rotation of drive eccentric disk 137 is effected by a rotary actuator assembly. In the embodiment illustrated, this comprises a shaft 162 journallcd wiUiin bearings 163 of housing 164, which is boiled to side walls 13 with axis concentric to disks 137, 138. Pneumatic or hydraulic cylinder 91, via crank arm 165, rotates shaft 162, which transmits essentially pure torsion force to disk 137 by way of splincd or square shaft end 166 or the like. The extension stroke of cylinder 91 is limited by abutment of the roller 69 shoulders against wheel rim tracks 5,6. The retraction stroke limit, as shown, is adjustable by slop-screw 169, as carried on bracket 168 attached to housing 164, against pin 167 which rolalcs inlcgrally with shaft 162. Operated pneumatically, this provides for pressure control of roller 69 against casl mclal section surface 104 during stroke extension, providing for section movements, dimensional and surface irregularities whilsl maintaining effectively constant roller force. Alternatively, operating with cylinder retracted extension air pressure, provides for positional containment only, even allowing the casl scclion lo release from Ihc wheel, according lo the setting of stop-screw 169. The roller segment assembly 90 is adaplcd to provide combined air-water cooling via air manifold 139 and water manifold 140 feeding spray block 141 into air-most noz/lcs 142, as well as spray water only, onto rollers 69 via water nozzles 144. As shown, these segments arc not enclosed, although they could be so arranged if desired. Scgmcnl-lo-scgmcnl hinging and segment balancing assemblies arc analogous to those of the mold segments 10, as illustrated. 11 will be appreciated that a rotary wheel casting machine has been described and illustrated and thai modifications and varialions may be made by those skilled in the art, without departing from the scope of the invcnlion defined in the appended claims. WE CLAIM: 1. A continuous casting machine comprising a rotary wheel incorporating a circumferential inner-radius mold wall (8) with two parallel annular inner mold-wall edges (9), integral with tile wheel rim; a non-rotating casting-mold sector (II) comprising at least one rigid mold segment (10) incorporating an outer-radius mold wall (12) having two outer mold-wall edges (21) which are parallel to, and interface with, said inner mold-wall edges (9), forming a casting mold envelope (43) between said-inner (8) and outer radius (12) mold walls; molten metal pouring means for introducing molten metal proximate the entry end (42) of said mold envelope (43) to pass through in the casting direction of circular wheel rotation and partially solidify a cast metal section for exit from the exit end (20) of said mold envelope (43); external support means of said segment (10) to maintain it in a fixed angular position in relation to said wheel; reciprocal oscillation means connected to said segment (10) to effect relative annular oscillation movement of said outer radius mold wall (12) alternately in said casting arid reverse directions in relation to said support means and thereby between said outer-radius mold wall (12) and said solidifying cast metal section, characterized in that: at least one annular outer-radius mold-wall edge guide track (5,6) integral with said rotary wheel proximate the wheel rim and which is parallel to said parallel mold-wall edges (9,21); and at least one guide track follower (15) fixed to said segment (10) in contact with said guide track (5,6) during rotation of said wheel, to maintain a constant dimensional clearance between said inner-radius (9) and outer-radius (21) mold-wall edges. 2. A continuous casting machine as claimed in claim 1 which has two of said edge guide tracks (5,6), one located on either side of the central plane of rotation of said inner-radius mold wall (8), arid also having at least two of said guide track followers (15) for each of said guide tracks (5,6), and wherein said followers comprise cam roller followers (15) in contact with said tracks (5,6). 3. A continuous casting machine as claimed in claim 1 which has two of said guide tracks (5,6), one located on either side of the central plane of rotation of said inner-radius mold wail (8), and also having at least two of said followers (15) for each of said guide tracks (5,6), and wherein said followers comprise cam follower rollers (15) which run in contact with said tracks (5,6) and incorporate means of restraining relative movement in the axial as well as radial direction of said rollers (15) relative to said track and thereby between said inner (9) and outer (12) mold-wall edges during wheel rotation and in which the radial guide surfaces of each said guide tracks (5,6) face radially outwards from the rotation axis of said wheel, and said cam follower rollers (15) ride on these surfaces and thereby do not restrain said segment (10) from movement in the radially outward direction, wherein said wheel carries another annular balancing guide track (25) with faces directed radially inwards complementary to each outward-facing track (5,6), against which rides at least one balancing cam follower (27) attached to said segment (10), thereby maintaining contact between said guide track followers (15) and said guide track (5,6) by radially restraining movement of said segment (10) in the direction radially outwards from said wheel. 4. A continuous casting machine as claimed in claim 1 wherein said mold segment (10) comprises a rigid, semicircular box enclosure having two side walls (13), an outer cover wall (143), a top entry-end wall and a bottom exit-end wall, and an inner wall carrying said outer-radius mold, wall (12) on its inner radius, coolant spray nozzles (38) contained within said enclosure directed radially inwards, and means for pressurized fluid coolant supply to said nozzles (38), thereby being to direct coolant sprays (39) directly against said oilier-radius mold wall (12); and a coolant exit duct (40) proximate said bottom exit-end wall for draining spent coolant from within said enclosure by gravity. 5. A continuous casting machine as claimed in claim 1 wherein said inner radius mold wall (8) is integral with an annular casting wheel mold ring (93) and said guide track (5,6) comprises the annular rim of said mold ring (93), which has coolant sprays (159) directed to impinge radially outwards against the inside surface of the said ring, for removal of heat conducted radially inward through the body of said mold ring (93). 6. A continuous casting machine as claimed in claim 1 which has two of said guide tracks (5,6), one located on either side of the central plane of rotation of said inner-radius mold wall (8), arid also having at least two of said followers (15) for each of said guide tracks (5,6), and wherein said followers (15) comprise cam follower rollers (15) which run in contact with said track (5,6) and incorporate means of restraining relative movement in the axial as well as radial direction of said rollers (15) relative to said track and thereby between said inner (9) and outer mold-wall edges (21) during wheel rotation and in which the radial guide surfaces of each of said guide tracks (5,6) radially outwards from the rotation axis of said wheel, and said cam follower rollers (15) ride on these surfaces and thereby do not restrain said mold segment (10) from movement in the radially outward direction, which also has a balancing assembly for said segment (10) comprising: a support frame (147) mounted on a fixed external support (148); a moveable carriage (146) guided from said support frame (148) carrying al least one balancing cam roller (114) positioned to exert pressure radially inwards against an annular (rack (115) integral to said segment (10) and thereby maintain each of said guide track followers (15) pressed radially against said guide track (5,6) during rotation of said wheel; and controlled radial pressure actuation means (145) for said carriage (147) to adjust and maintain a controlled radial force of said balancing cam roller (114) against said track (115) during operation whilst allowing reciprocating annular oscillation of said segment (10). 7. A continuous casting machine as claimed in claim 5 or claim 6 which has two or said edge guide tracks (5,6), each of which comprise opposite edges or said mold ring (93), one located ofl. either side or the central plane of rotation of said inner-radius mold wall (8), and also having at least two of said guide track followers (15) for each of said guide tracks (5,6). 8. A continuous casting machine substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Full Text

ROTARY WHEEL CASTING MACHINE'
The invention relates to the continuous casting of slccl and other mclals and, more particularly, to an improved rolary wheel-type casting machine for continuous casting of billets, blooms, slabs, bars, rods and the like.
In the prior art of vertical continuous casting wheels, peripheral closure of the casting mold channel generally is accomplished by cither a moving, endless metal bell pressed against the wheel rim by rollers to realize closure and synchronous peripheral motion with the wheel, or by multiple closure segments, or clamshcll-stylc molds, spaced in abutting sectors around the entire wheel circumference and rotating with it, which arc closed proximate the point of pouring steam entry, and reopened at bar exit from the casting sector during each revolution of the wheel. Known technology also includes n stationary closure bell, pressed in friclional contact against the wheel periphery spanning the casting arc.
Disadvantages of the endless bell include: heal from the casting warps the belt, also imparting a wrinkled and warped surface to the cast slock on the belt side of the section; return rollers arc bulky and occupy useful space; a closed and scaled collector and conduit for spent bell-cooling wntcr is difficult, if not impossible, lo realize; bells require a regular schedule of replacement through wear and warpngc; bells do not maintain uniform contact and pressure to hold the casting firmly against Ihc wheel as the casting proceeds arourtd the wheel; and maximum width of cast stock is very limited due lo belt flexure and warpagc. Despite these disadvantages, most commercial production machines employ a moving endless flexible metal belt to effect mold closure.
Disadvantages of scgrncnlcd molds include mechanical complexity with inherently very large number of cooperating parts and components; difficulty in maintaining necessary close tolerances between large number of interacting wheel sectors usually 24 or 36, each sector including a clam-shell mold pair, inlet-outlet water piping, mechanical hinging and actuation; problems with metal and slag splashes interfering with mold closure and mold-mold interfaces; and additional tundish pouring clearance necessary to accommodate individual mold sector height above metal meniscus.
Disadvantages of the slalic closure arc incidence of slicking between Ihc moving surface of the initially solidified slock and Ihc stationary surface of the closure, resulting in possible skin ruptures and the like; also wear and operating problems associated willi contact friction between wheel perimeter surface and the closure surface.
Casting wheels having an oscillating closure have also been proposed. These have not offered practical support of the oscillating casting shoe assembly along with close control of the clearance
dimension between channel edge surfaces and the mating edges of the oscillating shoe, or o low-incrtin closure assembly allowing rapid oscillation, in combination with close clearance control. Further, the prior art lacks means for precise positioning of containment rollers relative to the wheel rim, along with control of the containment roller pressure against the cast section below tlic mold, together with capture and disposal of spent coolant, as an integral part of the wheel assembly, rather than of a bulky external structure without coolant capture. Practical means for changing the width of cast slab sections, without changing molds, is also not evident in die prior art of rotary wheel casters.
It is a principal object of this invention to provide a rotary wheel continuous casting machine which docs not have the disadvantages cited above for prior art casting wheels.
Another object is to provide a casting machine which rcali/.cs a much higher output per strand of equivalent cross-section than do conventional vertical, curved or hori/x)iilal casting machines, and thereby can involve less cost and complexity for equivalent output.
A further object is to provide, in various embodiments, a casting machine capable of casting billet and bloom type sections for rolling into rod, bar and tubing sections and, in a modified embodiment, flat slab sections suitable for subsequent rolling into plate, sheet and strip products, with the invention particularly suitable for casting near net shape products such as thin slabs and beam blanks. Varying the width of slab section without changing the wheel channel is a related object.
An additional object is to provide a casting machine in which the principal force and pressure propelling the cast section forward is inherently effected at the location of the cross section being cast, rather than by the pulling force and tension created by tlic withdrawal pinch rollers following exit from the casting mold and containment spray chamber area, thus eliminating the main source of skin stresses and tears, with associated substantial increase in casting rale.
A still further object is to provide a casting machine capable of casting product with very good surface and internal metallurgical quality.
The invention comprises basic features in common with the prior art, namely a rotary wheel continuous casting machine comprising a rotary wheel incorporating a circumferential inner-radius mold wall with two parallel annular inner mold-wall edges, integral to the wheel rim; a non-rotating casting-mold sector (11) comprising at least one rigid mold segment (10), incorporating an outer-radius mold wall having two outer mold-wall edges (21) which arc parallel to, and interface with, said inner mold-wall
edges (9), forming a casting mold envelope (43) between said inner (8)and outer-radius (12) mold walls; molten metal pouring means adapted for introducing molten metal proximate the entry end (42) of said mold envelope (43) to pass through in the casting direction of circular wheel rotation and at least partially solidify a cast metal section for exit from the exit end (20) of said mold envelope (43); external support means of said segment (10) adapted to maintain it in a substantially fixed angular position in relation to said wheel; reciprocal oscillation means connected to said segment (10) adapted to effect relative annular oscillation movement of said outer radius mold wall (12) alternately in said casting and reverse directions in relation to said support means and thereby between said outer-radius mold wall (12) and said solidifying cast section jlhc invention comprising combination of these with: at least one annular outer-radius mold-wall edge guide track (5,6) integral to said rotary wheel proximate the wheel rim and which is parallel to said parallel mold-wall edges (9,21); and at least one guide track follower (15) fixed to said non-rotating segment (10) which is maintained in conlacl with said guide track (5,6) during rotation of said wheel, adapted to maintain a substantially constant dimensional clearance between said inner-radius (9) and outer-radius (12) mold-wall edges.)
A preferred embodiment includes two of said guide tracks (5,6), one located on cither side of the central plane of rotation of said inner-radius mold wall (8), and at least two of said followers (15) for each of said guide tracks (5,6), and said followers comprise cam roller followers (15) which run in conlacl with said track (5,6) and incorporate means of restraining relative movement in the axial as well as radial direction of said cam roller followers (15) rclalivc lo said track and thereby between said inner (9) and outer (12) mold-wall edges during wheel rotation.
The radially guiding surfaces of each said guide track (5,6) typically face radially outwards from the rotation axis of said wheel, and said cam follower rollers (15) ride on Ihcsc surfaces and thereby do nol restrain said casting-mold segments (10) from movement in the radially oulward direction. In one embodiment, the wheel carries another annular balancing guide track (25) with faces directed radially inwards, complementary lo each oulward-facing track (5,6), against which rides al Icasl one balancing cam follower (27) attached lo said non-rotaling casling-mold segment (10) thereby maintaining conlacl between said guide track followers (15) and said guide track (5,6) by radially restraining movement of said casting mold segment (10) in the direction radially outwards from said wheel. In another embodiment, the casting mold segments (10) also carry a supplementary guide track (115) against which fluid-pressure loaded balancing cam followers (114) maintain continuous pressure and conlacl of the guide track followers (15) against the wheel rim, with the balancing followers (114), in turn, being supported and positioned from a fixed support of me machine housing, or the like. The supplementary Irack preferably includes a reverse capturing flange (116) for the balancing follower, enabling the casting
segments to be lifted off the wheel and held in suspension during inspection or maintenance.
Mold segments (10) most suitably comprises a rigid, semicircular enclosure having two box side walls (13), a box outer cover wall (143) and a box inner wall carrying said outer-radius mold wall (12) on its face, in which said external support means and said oscillation means arc attached to the segment (10), thereby being adapted to oscillate said outer-radius mold wall (12) back and forth in the circumferential direction about a substantially fixed angular location on the casting wheel periphery. Spray nox/lcs (38) arc suitably contained within said enclosure directed radially inwards, to spray coolant directly against said outer-radius mold walls (12) and spent coolant is confined within the enclosure and discharged via an appropriate outlet duct (40). Alternatively, the enclosure may form a prcssuri/cd water jacket, internally baffled to provide an annulus for flow of prcssuri/cd coolant against the outside of mold-wall (12). Appropriately, there arc four studded cam roller track followers (15), with two mounted to project outwardly from each box side wall (13) of segment (10), and two balancing cam roller assemblies, one mounted on the outside of each side wall (13) of segment (10) intermediate between said track followers (15), including means for applying a continuous controlled pressure of the balancing rollers (27) against die tracks (25), sufficient to maintain the guide track followers (15) in continuous contact with the outward-facing guide tracks (5,6).
Another aspect of the invention provides a containment-roller sector (28) adjoining the mold envelope exit end (20), similar to the casting mold sector (11) but carrying transverse containment idler rollers (69) journallcd in bearings (72) supported by the segment side walls (13), with faces positioned and adapted to press radially inwards against the outer face of the section being cast to maintain the inner face of the section pressed against the inner-radius mold wall (8), the tangential component of this pressure acting to exert a circumferential forward propelling force on the section in the casting direction. Means arc provided for controlling the radial movement and pressure of these rollers (69) against the face of the section being cast.
Other aspects of me invention include apparatus for positioning of movable side-dam bars (44) adapted for varying the width of the metal section being cast; a tangential departure (67) of the outer mold-wall at the entry end (42) of the mold envelope to provide improved access for introducing liquid metal; a mold closure guiding arrangement applicable to spray-cooled solid-block copper casting wheel mold rings (93); and a universal hinge coupling assembly (120) connecting adjoining segments (10, 90) which allows each individual to track independently on the wheel rim, without coupling backlash.Various oilier objects, features and advantages of the process and apparatus of this invention will
become apparent from the following detailed description and claims, and by referring to the accompanying drawings, in which:
Accordingly the present invention relates to a continuous casting machine comprising a rotary wheel incorporating a circumferential inner-radius mold wall (8) with two parallel annular inner mold-wall edges (9), integral with tile wheel rimJ
a non-rotating casting-mold sector (II) comprising at least one rigid mold segment (10) incorporating an outer-radius mold wall (12) having two outer mold-wall edges (21) which are parallel to, and interface with, said inner mold-wall edges (9), forming a casting mold envelope (43) between said-inner (8) and outer radius (12) mold walls!
molten metal pouring means for introducing molten metal proximate the entry end (42) of said mold envelope (43) to pass through in the casting direction of circular wheel rotation and partially solidify a cast metal section for exit from the exit end (20) of said mold envelope (43) ! external support means of said segment (10) to maintain it in a fixed angular position in relation to said wheel;
reciprocal oscillation means connected to said segment (10) to effect relative annular oscillation movement of said outer radius mold wall (12) alternately in said casting arid reverse directions in relation
to said support means and thereby between said outer-radius mold wall (12) and said solidifying cast metal section, in-combination witlv
at least one annular outer-radius mold-wall edge guide track (5,6) integral with said rotary wheel proximate the wheel rim and which is parallel to said parallel mold-wall edges (9,21); and at least one guide track follower (15) fixed to said segment (10) in contact with said guide track (5,6) during rotation of said wheel, to maintain a constant dimensional clearance between said inner-radius (9) and outer-radius (21) mold- wall edges.
Fig. 1 is an illustrative side view of a rotary wheel casting machine embodiment according to die invention, including a wheel sector illustrated in section, along the plane of rotation intersecting the mold
center line;
Fig. 2 is a section view along plane 2-2 of Fig. 1 incorporating a mold cavity of general shape suitable for
the casting of blooms, billets, bars and rods applicable to production of long products;
Fig. 3 is a section view along plane 3-3 of Fig. 1;
Fig. 4 is a side view of the apparatus illustrated in Fig. 3; and
Fig. 5 is a corresponding section view to that illustrated in Fig. 2 incorporating a mold cavity of general
shape suitable for casting slabs, plates, sheets mid strip, as applicable to the production of flat-rolled
products;
Fig. 6 is a partial front elevation view of a mold-width adjustment mechanism adapted for casting various
flat-rolled product widths without changing the wheel mold;
Fig. 7 is a sectional view along plane 7-7 of Fig. 6;
Fig. 8 is an illustrative partial sectional view of an alternative embodiment substituting containment idler
rollers in place of the outer mold wall in the lower portion of the non-rotating casting sector;
Fig. 9 is a partial lop view along plane 9-9 of Fig. 8
Figs. 10, ajid 11 illustrate two variations for containment idler roller bearing support, positioning and
pressure application;
Fig. 12 is a corresponding section view of that illustrated in Figs. 2 and 5, incorporating a mold cavity
adapted for the near net shape casting of structural sections and the like;
Fig. 13 is a split cross-section illustration of a containment roller segment embodiment;
Fig. 14 is a partial side view of the roller segment of Fig. 13;
Fig. 15 is a side elevation view of an entry mold scgmcnl assembly;
Fig. 16 is a section view along plane 16-16 of Fig. 15;
Fig. 17A is a section view along plane 17A of Fig. 15;
Fig. 17B is a section view along plane 17B of Fig. 15;
Fig. 18 is a section view along plane 18-18 of Fig. 16;
Fig. 19 is a side elevation general arrangement view of an embodiment incorporating mold and roller
segment balancing devices supported directly from the fixed machine frame;
Figs. 20, 21 and 22 illustrate details of the externally supported balancing assemblies as shown in Fig.
19;
Fig. 23 is a section view of a suitable segment oscillator assembly;
Fig. 24 is a section view along plane 24-24 of Fig. 23;
Fig. 25 is a side elevation view of a containment roller segment embodiment, Fig. 26 is a section view along plane 26-26 of Fig. 25; Fig. 27 is a section view along plane 27-27 of Fig. 25; Fig. 28 is a section view along plane 28-28 of Fig. 25; and Fig. 29 is a section view along plane 29-29 of Fig. 27.
Referring to the drawings, wheel hub assembly 1, is journallcd upon bearings mounted on fixed supports and the rotated by an appropriate electro-mechanical or hydraulic drive unit, preferably at variable and controlled speed. In the embodiment illustrated, the rotary wheel structure comprises o solid-disc body 2 with radial sliffcncr ribs 19 spanning between hub 1 and U-shaped wheel rim 24, also defining cooling water jacket annulus 4. A typical wheel sue would be 2-4 meters in diameter, although a wide range of sizes arc possible. It is to be appreciated that a substantial part of the drawings arc diagrammatic only, particularly regarding aspects known in the art. Wheel mold cooling water is introduced, and spent water discharged, via appropriate rotary union assemblies incorporated into hut) assembly 1, supplied to and returned from wheel rim 24 via appropriate wheel mounted water pipes 35. The details of tins aspect and numerous other features of the wheel casting machine ore not shown or described herein, being well known in the art, and with many known and obvious options as to selection and configuration available.
Casting wheel rim 24 carries annular inner radius mold-wall support rings 3 and also two outer-radius mold-wall edge guide tracks 5, 6 comprising cylindrical radial surfaces, directed radially outward, one on cither side of axial central plane of rotation 7 of the inner radius mold wall, in the embodiment illustrated. The inner radius mold-wall 8 may also include side faces 18 extending radially outwards, as in the embodiment illustrated for casting of a square cross section, approximately at right angles to the inside face of mold wall 8. The mold wall usually of copper or copper alloy, is fastened to support rings 3 such as by screws spaced around the wheel rim periphery. On most casting wheels, side faces 18 arc tapered to diverge transversely outwards, for example, at a slope of 1 or 2 per cent, thereby assuring clearance for tangential discharge of the cast metal section at exit 20, without edge friction or binding between the section and side faces 18.
Non-rotating casting mold sector 11 incorporates outer radius mold-wall 12 as its inner face thereby forming a casting mold envelope 43 between said inner 8 and outer 12 mold walls. Sector 11 may comprise a single rigid circumferential mold segment or be made up in multiple mold segments 10. In Uic embodiment illustrated, sector 11 comprises three rigid semicircular mold segments 10 having the abutting ends of segment side walls 13 interleaved and connected together by hinge pins 14. Each
segment 10, in turn, lias four cam truck followers 15 mounted on side walls 13 as two opposite pairs, positioned to run in contact with guide tracks 5,6. Appropriately, the roller mounting studs incorporate eccentric bushings 16, lo enable easy adjustment of the clearance 17 between the interfacing inner 9, and outer 21, parallel annular mold-wall edges. Adjustment of these clearances, in the embodiment illustrated, may be effected manually using an Allen wrench applied to a hexagonal socket in the stud end of cam roller 15, whilst measuring the clearances with feeler gauges. Clearances down lo Uic 25 micron area can be accomplished without any contact across the interface, thus emulating a continuous mold wall whilst avoiding wear and galling of these mating surfaces. At typical casting temperatures approaching the liquidus, the combined parameters of surface tension, viscosity and transient solidification in the presence of cold, high-conductivity mold wall material, generally then preclude entry of metal between the mold-edge faces proximate the meniscus. The rollers 15 arc also provided with flanges 22 lo ride against circumferential transverse alignment guide surfaces 23, incorporated into guide tracks 5,6 to maintain transverse (sidc-to-sidc) outer mold-wall alignment. Segment-mounted radially-slidablc brackets, or llic like, of course may be employed lo augment, or as alternatives lo, the eccentric bushings 16 for adjustment of track follower position and thereby clearance 17. Oulcr-radius mold wall 12 may be transversely contoured, for example, recessed between the edges to provide a rounded billcl corner and eliminate the sharp right-angled comer at 17 characteristic of a flat plate shoe, a source of possible rolling mill difficulty.
In order to hold each mold segment 10 in place and assure continuous contact of cam rollers 15 will) guide tracks 5, 6 during the course of rotation and application of pressure from Uic section being cast, the inner mold-wall support rings 3 also include a second set of annular balancing guide tracks 25 directed radially inwards, against which ride balancing cam followers 27. In the embodiment illustrated, there is one set comprising two of these rollers 27 applied lo each hinged mold segment 10, cacli set counteracting llic corresponding two sets of rollers 15, leveraged to apply approximately equal force lo each set. The rollers 27 arc mounted on balancing slide arm 29, guided for movement in Uic radial direction only within support ring side bracket 30, and stroked by balancing cylinder 31. Such balancing actuators can be powered by any approprialc fluid, bul compressible gases such us air have a clear advantage when in a pressure-control mode of this application, by compensating for wheel and track eccentricity and irregularity displacements wiUioul use of supplementary proportional or servo control valves or Uic like to meter fluids back and forth. Oscillation of segment 10 along Uic paUi defined by cam rollers 15 along tracks 5,6 is effected, such as by hydraulic oscillator 32 acting between rolalablc bracket 33 fixed lo segment 10 and externally fixed support bracket 34. A wide range of forms of hydraulic and electro-mechanical oscillators as well as casling control systems, arc known in the art of continuous casting.
The inner mold walls arc appropriately force water-cooled with water supplied and returned via at least one set of wheel-mounted water pipes 35. Each segment 10 is supplied with coolant, usually water, via an inlet through box side walls 13 or outer cover wall 143 into enclosed hcndcr pipe 37 feeding coolant spray noz/lcs 38 which direct the coolant spray 39 to impinge on the exterior surface of outer radius mold-wall 12. Spent coolant flows by gravity through outlets 40 into appropriate hosing to a sump or the like, usually for rccirculalion. Ease of coolant enclosure, as compared to flexible belt casters, is also to be noted. Removable cover plates 41 incorporated into segments 10 provide access to the sprays for maintenance and the like, as well as rotation adjustment of cam roller eccentric bushings 16. These preferably include quick-release fasteners and seals.
Start-up and operation arc conducted in essentially the same manner as a conventional flexible-bell machine, molten metal being poured from tundish 36 into the entry end 42 of mold envelope 43 and the cast metal section withdrawn from the exit end 20 by means of powered withdrawal rolls 26, details omitted as well-known.
Fig. 5 illustrates an embodiment adapted for casting of thin slab products. Except for the shape and si/c of the mold envelope, it will be seen that the basic machine features arc essentially the same as those for casting billets and blooms, as illustrated by Figs. 2 and 3.
Figs. 6 and 7 illustrate a supplementary apparatus to facilitate the casting of various slab widths without major equipment modifications or substitutions. Rather than confinement of the cast section between side faces 18 of the inner radius mold wall 8, the side faces 89 of partially solidified thin slab 61 arc confined between the two movable mold side-dam bars 44, also fabricated and machined on an arc to a clearance fit between inner 8 and outer 12 mold wall faces. Bars 44 arc confined transversely between side alignment brackets 47 of movable carriage 46, and circumfcrcntially by the interaction between pin 50, as fixed to carriage 46 by bracket 48, and mold side-dam oscillator bracket 49. Carriage 46 is carried on two pairs of vcc-guidc rollers 53 which run on transverse guide track 51, providing linear guided movement only in the transverse direction. Track 51, in turn, is fastened to track support bracket 52 attached to segment 10, and thereby transmits the corresponding circumferential oscillation movement of the outer mold wall to mold side-dam bars 44. Rollers 53 arc preferably mounted on eccentric bushings 62, providing for easy and accurate adjustment of alignment and clearance with guide track 51. By providing a close fit between side brackets 47 and bar 44, these bushings also facilitate precise adjustment of the transverse slope of bars 44.
Carriages 46 arc fixed transversely by threaded take-up nuts 59 riding on support bracket 60,
variably positioned axially by rotation of opposite-hand threaded carriage drive screws 58, as driven by centrally located hydraulic traverse motor 54. As illustrated, this is a hollow-shaft motor mounted on splined drive shaft 64, as carried between flange bearings 56 of motor support bracket 55, in turn fixed to the outer wall of box enclosure 10. Torque couple-arms 66 act against torque pins 63 to prevent motor body rotation. Shaft 64, in turn, is connected at cither end to drive screws 58 by couplings 57. Mold side-dam bar 44 appropriately comprises a rectangular lube of copper alloy, blanked off at both ends, with coolant provided via flexible hoses connected into coolant inlet and outlet connections 45, one of which is internally piped to the bottom extremity of side-dam bar 44. The faces of bar 44 may also be drilled for lubricant ducts and outlets, to provide face lubrication, such as by rapcsccd oil during operation.
During casting, it is well known that the stock cross-section progressively shrinks with cooling and solidification during its descent within the mold, and also that the outer layer of "skin" of the casting is effectively self-scaling once a continuous surface has been formed around the casting perimeter, unless stresses arc present sufficient to create a rupture and associated "break-out" of molten metal. In conventional oscillating mold casters, substantially all of the withdrawal force is usually applied following discharge from a roller spray chamber, or as assisted by a selected few driven rollers within the spray chamber containment area. The forces arc thus applied at a remote point from the solidifying section at mold exit, or a limited number of selected points along the casting length, relying on bar skin tension/compression strength between these points to maintain casting integrity. Because of the stresses this creates, a relatively thick fro/cn skin is necessary at mold exit, substantially limiting the maximum casting speed, to allow sufficient time for formation of this skin.
Within the mold envelope, a taper can be added to the outer-radius mold walls 12 by graduating the portion of the face of outer-radius mold walls 12 within sides 18. In addition, Fig. 8 shows a variation including a containment roller wheel sector 28 incorporating containment roller segments 90 which carry containment idler rollers 69, in place of outer radius mold-wall 12, with coolant sprays 39 thereby impinging directly upon the surface of the cast metal section. Along the arc of wheel sector 28, the withdrawal forces can then be applied directly by the rollers 69 at the cross section being cast, by mninlaining static friclional contact and pressure between the stock skin surface and the inner radius mold walls 8, as they move and propel the casting along al essentially identical surface speed. Tcnsional casting slrcss is thereby nearly eliminated, allowing a very substantial increase in practical casting speed for similar effective mold lengths. Since the casting wheel rotation is furnishing the propulsive force, the powered withdrawal rollers 26 arc also usually superfluous. For casting wide slab sections, rollers 69 may also be split into multiple lengths incorporating intermediate segment-supported bearings.
It is obvious thai minor leakage of spent cooling water can lake place via clearances 17, in the absence of scaled contact between side walls 13 and inner mold-wall edges 9. A supplementary seal may be added lo minimize tliis leakage (not illustrated). Suitable practice could provide on the order of o meter of wheel arc, e.g. one box enclosure 10 at the top, ns illustrated, incorporating outer mold walls 12 and the two bottom segments 90 be equipped with rollers 69. It will also be obvious that only the lop sector 11 need be oscillated, as an option. One or more of ihc conlainmcnl rollers 69 may also be applied lo cffccl thickness reduction of llic casl metal section by increasing Uic roller pressure, optionally including liquid core reduction when the scclion is only partially solidified. These rollers may be undrivcn idlers or, alternatively, powered so as lo rolalc Ihc roller surface at a rale synchronized with Uic surface speed of Ihc casl mclal section.
For starling of casling, a starter block or starter bar is usually inserted into Ihc mold cavily, designed lo move in unison with the wheel once casting commences. When Ihc block can be confined between the wheel rim and conlainmcnl rollers, only a relatively short slarlcr bar is required or, allcrnalivcly, a shorl starter block head having a longer, flexible elastomer bar attached, which can be hollow and contoured lo fit snugly in Uic wheel groove, in order to assisl with scclion guidance following cxil from the machine. The block characteristically includes a protruding top hook or claw designed lo hold the starter block and freshly casl metal together in one piece until llicy arc separated following exit.
One praclical difficulty in Uic casling of thin slab product is Uic desired narrow slab thickness in relation to Uic dimensions of submerged-entry nozzles. Figs. 8 and 9 illustrate means to miligalc Uiis problem by a funnel-shaped departure on only Uic oulcr-radius mold wall at Uic nozzle 65, wherein wall 12 is extended vertically and langcnlially upwards, as at 67, al right angles lo Uic wheel horizonlal center line 80 in Uic plane of rotalion of Uic wheel, al Uic Iransvcrsc location of submerged entry nozzle 65, on cither side of which mold-wall 12 is graduated into the slraighl-sidcd cylindrical wall, in Uic form of a half funnel-segment 68 wiUi maximum widUi al Uic location of molten metal entry 42. In Uic embodiment illustrated, where Uic Uiickncss of nozzle 65 is nearly equal lo Uic casling thickness, it may be seen Uiat adcqualc insertion is oblaincd, including good wall clearance, by vcrlical insertion of nozzle 65 parallel lo this vcrlical funnel wall.
Fig. 10 illustrates simple means of maintaining position and controlled pressure of Iransvcrsc conlainmcnl rollers 69 against Uic outer scclion surface. The roller shafts 71 arc journnllcd within scaled cartridge bearings 72, riding in guided chocks 73, as recessed in Uic structure of side-walls 13 of segment 90. The chocks 73 and thereby rollers 69 arc loaded and rclraclcd by air or hydraulic cylinders 70,
through which the position or force of each roller against the cast metal section surface 104 can be adjusted.
Fig. 11 illustrates another means of supporting and controlling rollers 69, whereby the outer race of bearings 72, mounted on roll shaft 83, arc carried within an eccentric bushing 76. Rotating means for bushing 76, such as a pivotally mounted cylinder or rotary actuator (not shown) actuating lever arm 77 of the bushing, can effect both controlled pressure and controlled position of roller 69. Cooling water can also be supplied via rotary union 78 through internal ducting within shaft 83 to roll water cooling annul us 79. The bearings 72 can also be located outside of wall 13 in other embodiments, such as by extension of shafts 71, 83 shown in Fig. 10 or Fig. 11.
Fig. 12 illustrates an embodiment in which the mold envelope is in the form of a near net shape structural beam blank. It will be evident that a variety of such mold shapes and sixes can be applied as variations on the basic features of the apparatus of the invention.
Figs. 13 and 14 illustrate a containment roller segment variation, in conjunction with a wheel in which a spray-cooled copper block mold ring 93 comprises the wheel rim, combining the functions of inner mold wall 8 and annular outer radius mold wall edge guide track 6. Cam roller track followers 15 ride directly on the mold rim, (guide track 5,6) with flanges 22 riding against bevelled edge surface 94 of mold ring 93. Balancing rollers in this case may more conveniently be mounted to act between the roller segment and a fixed support attached to the machine base, backing frame or the like, rather than the rotating wheel. Mold ring 93 is appropriately cooled by means of inside coolant sprays 159 and side sprays 160. Roll shaft 84 is fixed, except for rotation together with externally eccentric bushings 85 keyed or otherwise fixed to shaft 84, and also concentrically supports the inner race of bearing cartridge 72 carrying roller 69 on Ihc outer races. Pneumatic or hydraulic cylinders 91 function similarly to rotary actuators by stroking eccentric lever arm 92 to control position and pressure of containment rollers 95 against the outer surface 104 of the solidifying cast metal section. This arrangement facilitates close control of Uic face position of roller 69 in relation to surface 104, such as by precise positioning of cylinder 91, for example, employing position sensors for the rod of a hydraulically operated cylinder, including a transducer to accomplish remote electronic automatic position control, to maintain set-point positions. In a case where roller pressure control only is deemed required, the rollers could be directly and individually supported with reference to the machine base or backing plate only, eliminating rollers 15,22 and allowing radial roller position to follow Uic variations in position of casting surface 104 as Die wheel rotates, cylinder 91 being operated pneumatically. Lever arms 92 of adjacent rollers may also be linked together providing for actuation of two or more rollers 69 with one cylinder, but with the potential
disadvantage of unequal roller pressures or stock-lo-rollcr clearances occurring. In order to allow adjustable roll positioning, in combination with a full retraction away from the wheel for maintenance and the like, a three-position duplex cylinder or equivalent could be employed in place of single cylinder 91.
Figs. 15, 16, 17A& 170 and 18 illustrate additional or alternative embodiments of the mold segment apparatus 10. This includes a prcssuri/cd water-filled inlet chamber 106 separated from outlet chamber 107 by dividing wall 108, incorporating baffle plate 109, as held in position by draw-bolts 110, to assure high-velocity water flow within annulus 111 for cooling of outer radius mold wall shoe 112. Draw-bolls 110 arc scaled by way of an appropriate 0-ring gland 113. The oulcr radius mold wall shoes 112 arc scaled by an claslonicr-coalcd metal gasket 130 and fastened in position by screws 131. Among oilier features illustrated is a cental mold overflow channel 149 at mold entry, to reduce the risk of molten metal jamming the entry junction between wheel and outer mold wall, should overflow conditions occur during casting. The balancing assembly is based upon on external support frame, to locale and control the force of flanged rollers 114 against balancing track 115. Rollers 114, in turn, ore mounted with clearance but captured within retention flange 116, thus providing for retracting the segments radially outward and oil" the wheel lo hold them in essentially fixed position when desired for mold inspection, maintenance, changing of wheels and the like.
This segment embodiment includes substantial radial adjustment of track followers 15, in view of the much lower cost of re-machining used oulcr radius mold wall shoes I 12 after use; in comparison with replacement with new ones. Adjusting screw 122 effects adjustment of pillow blocks 121, lobe held in position by locking screws 123. In order lo avoid potential axial segment yawing and vibration, one of the followers 15 of each opposing pair is spring-preloaded transversely by way of compression spring 124 acting between cap 125 and the face of linear bushing 126, thus maintaining continuous running conlacl bclwccn flanges 22 and inner mold edges 94. Side-guide follower rollers, having one of each pair spring or fluid pre-loaded is a more elaborate alternative not illustrated. A single universal hinge-coupling assembly 120 connects adjacent segments together, comprising opposed spherical plain thrust bearings 117, thrusting against end flanges 82 of segments 90 confined by bolt-and-nul assembly 118 and at an adjustable distance of separation bclwccn flanges 82, and also incorporating pre-load spring 119 with spring rale force sufficicnl lo eliminate clearances and any backlash, whilst allowing both Iransvcrsc and angular misalignment bclwccn segments. As applied to mold segments 10, in order to accommodate mold shoe thermal expansion in Ihc cvcnl Lhal adjacent mold shoe ends arc closely bulled together at slart-up, Belleville spring-washers arc appropriately inserted bclwccn Ihc nuls and bearings 117, designed lo balance Ihc opposing force of spring 119, and wilh additional travel sufficient lo accommodate the expansion aflcr slarl-up.
Fig. 1713 also illustrates the variation of a contoured transverse profile of outer-radius mold wall 12 in which side faces 18 arc extended past clearance 17 into a recess of outer mold wall shoe 112. This eliminates the aculc angle at the section corner cnlcring into gap 17 and also allows a rounded corner 127 of the cast metal section. As otherwise illustrated to be flat, any metal flash into clearance 17 between shoe and wheel occurs at the section corner, rendering it difficult to hot roll or extrude without introducing lap surface defects or the like, whereby wheel-and-band casters usually mill off the corner flash prior to hot working. Contouring of the outer mold shoe face also extends the range of shapes and sizes which can be cast.
Flexible bond closure casting wheels commonly used for casting copper and aluminum billets and rods normally utilizc a much larger sector of the wheel than those for steel, that is, most commonly, entry is at 1-2 o'clock and exit at 9-10 o'clock position, rather than 3 and 6 o'clock. Fig. 19 illustrates the invention as applied to such a wheel, and with segment balancing effected by an air cylinder 145 mounted within a square lube 146, the extension of which carries the segment balancing rollers 114, and guided by sliding bearing pads 144 riding against the inner walls of another square lube 147 fixed to machine frame 148. Oscillator crank arm 99 transmits oscillating motion to mold segments 10, as generated by oscillator drive assembly 156, which is also supported by fixed machine frame 148. Figs. 20, 21 and 22 illustrate details of the segment balancing units as appropriately cantilcvcrcd out from a backing frame also supporting the main casting wheel hub and bearings. Please note that piping and wiring and the like is omillcd from Figs. 15-22 for clarity.
Fast casting speeds require rapid mold closure oscillation, towards maintaining sufficient negative strip with minimal surface oscillation marks. Figs. 23 and 24 illustrate a suitable oscillator, in which housing 95 carries bearings 96 for rotation of drive shaft 97 by means of adjustable speed hydraulic molor 98 as an alternative to air motor 74 with gear box and bell drive 75, as illustrated in Fig. 19. Eccentric crank extension 99 revolves around the center axis of shaft 97 carrying connecting rod drive bearing 105. In order to adjust the stroke length as indicated by the graduated index 155, location ring 154 of cantilcvcrcd stub shafl 150 is rotated by nut 151 and locked at the desired stroke length by bolted locking plate 152. Crank 99 may be connected directly to mold segment wrist pin 153. Thus, a sinusoidal reciprocating oscillation, of selected adjustable stroke length, is transmitted to Hie mold segments.
Figs. 25, 26, 27, 28 and 29 illuslralc additional or alternative embodiments of the roller segment apparatus 90. The roller eccentric assembly comprises drive eccentric disk 137 and driven eccentric disk 138 which arc equally eccentric to roller shaft 84 and keyed to it by parallel cross keys 134 and 135, as
fixed by dowels 136, thus comprising a rigid assembly to maintain parallel rotation of the shaft 84 axis about the axis of disks 137, 138. Containment idler roller 69, as supported by bearings 72, is then rolalablc about shaft 84 by frictional contact with the moving face of the cast metal section. Concentric disks 137, 138 rotate within concentric bushings 161 mounted within axially aligned circular apertures in opposite box side walls 13, and the rotation of drive eccentric disk 137 is effected by a rotary actuator assembly. In the embodiment illustrated, this comprises a shaft 162 journallcd wiUiin bearings 163 of housing 164, which is boiled to side walls 13 with axis concentric to disks 137, 138. Pneumatic or hydraulic cylinder 91, via crank arm 165, rotates shaft 162, which transmits essentially pure torsion force to disk 137 by way of splincd or square shaft end 166 or the like. The extension stroke of cylinder 91 is limited by abutment of the roller 69 shoulders against wheel rim tracks 5,6. The retraction stroke limit, as shown, is adjustable by slop-screw 169, as carried on bracket 168 attached to housing 164, against pin 167 which rolalcs inlcgrally with shaft 162. Operated pneumatically, this provides for pressure control of roller 69 against casl mclal section surface 104 during stroke extension, providing for section movements, dimensional and surface irregularities whilsl maintaining effectively constant roller force. Alternatively, operating with cylinder retracted extension air pressure, provides for positional containment only, even allowing the casl scclion lo release from Ihc wheel, according lo the setting of stop-screw 169. The roller segment assembly 90 is adaplcd to provide combined air-water cooling via air manifold 139 and water manifold 140 feeding spray block 141 into air-most noz/lcs 142, as well as spray water only, onto rollers 69 via water nozzles 144. As shown, these segments arc not enclosed, although they could be so arranged if desired. Scgmcnl-lo-scgmcnl hinging and segment balancing assemblies arc analogous to those of the mold segments 10, as illustrated.
11 will be appreciated that a rotary wheel casting machine has been described and illustrated and thai modifications and varialions may be made by those skilled in the art, without departing from the scope of the invcnlion defined in the appended claims.

WE CLAIM:
1. A continuous casting machine comprising a rotary wheel incorporating a circumferential inner-radius mold wall (8) with two parallel annular inner mold-wall edges (9), integral with tile wheel rim;
a non-rotating casting-mold sector (II) comprising at least one rigid mold segment (10) incorporating an outer-radius mold wall (12) having two outer mold-wall edges (21) which are parallel to, and interface with, said inner mold-wall edges (9), forming a casting mold envelope (43) between said-inner (8) and outer radius (12) mold walls;
molten metal pouring means for introducing molten metal proximate the entry end (42) of said mold envelope (43) to pass through in the casting direction of circular wheel rotation and partially solidify a cast metal section for exit from the exit end (20) of said mold envelope (43); external support means of said segment (10) to maintain it in a fixed angular position in relation to said wheel;
reciprocal oscillation means connected to said segment (10) to effect relative annular oscillation movement of said outer radius mold wall (12) alternately in said casting arid reverse directions in relation
to said support means and thereby between said outer-radius mold wall (12) and said solidifying cast metal section, characterized in that:
at least one annular outer-radius mold-wall edge guide track (5,6) integral with said rotary wheel proximate the wheel rim and which is parallel to said parallel mold-wall edges (9,21); and at least one guide track follower (15) fixed to said segment (10) in contact with said guide track (5,6) during rotation of said wheel, to maintain a constant dimensional clearance between said inner-radius (9) and outer-radius (21) mold-wall edges.
2. A continuous casting machine as claimed in claim 1
which has two of said edge guide tracks (5,6), one located on either
side of the central plane of rotation of said inner-radius mold wall
(8), arid also having at least two of said guide track followers (15)
for each of said guide tracks (5,6), and wherein said followers
comprise cam roller followers (15) in contact with said tracks (5,6).
3. A continuous casting machine as claimed in claim 1
which has two of said guide tracks (5,6), one located on either side
of the central plane of rotation of said inner-radius mold wail (8), and also having at least two of said followers (15) for each of said guide tracks (5,6), and wherein said followers comprise cam follower rollers (15) which run in contact with said tracks (5,6) and incorporate means of restraining relative movement in the axial as well as radial direction of said rollers (15) relative to said track and thereby between said inner (9) and outer (12) mold-wall edges during wheel rotation and in which the radial guide surfaces of each said guide tracks (5,6) face radially outwards from the rotation axis of said wheel, and said cam follower rollers (15) ride on these surfaces and thereby do not restrain said segment (10) from movement in the radially outward direction, wherein said wheel carries another annular balancing guide track (25) with faces directed radially inwards complementary to each outward-facing
track (5,6), against which rides at least one balancing cam follower (27) attached to said segment (10), thereby maintaining contact between said guide track followers (15) and said guide track (5,6) by radially restraining movement of said segment (10) in the direction radially outwards from said wheel.
4. A continuous casting machine as claimed in claim 1
wherein said mold segment (10) comprises a rigid, semicircular box enclosure having two side walls (13), an outer cover wall (143), a top entry-end wall and a bottom exit-end wall, and an inner wall carrying said outer-radius mold, wall (12) on its inner radius, coolant spray nozzles (38) contained within said enclosure directed
radially inwards, and means for pressurized fluid coolant supply to said nozzles (38), thereby being to direct coolant sprays (39) directly against said oilier-radius mold wall (12); and
a coolant exit duct (40) proximate said bottom exit-end wall for draining spent coolant from within said enclosure by gravity.
5. A continuous casting machine as claimed in claim 1 wherein
said inner radius mold wall (8) is integral with an annular casting
wheel mold ring (93) and said guide track (5,6) comprises the
annular rim of said mold ring (93), which has coolant sprays (159)
directed to impinge radially outwards against the inside surface of
the said ring, for removal of heat conducted radially inward
through the body of said mold ring (93).
6. A continuous casting machine as claimed in claim 1 which
has two of said guide tracks (5,6), one located on either side of the
central plane of rotation of said inner-radius mold wall (8), arid also
having at least two of said followers (15) for each of said guide
tracks (5,6), and wherein said followers (15) comprise cam follower
rollers (15) which run in contact with said track (5,6) and
incorporate means of restraining relative movement in the axial as
well as radial direction of said rollers (15) relative to said track and
thereby between said inner (9) and outer mold-wall edges (21)
during wheel rotation and in which the radial guide surfaces of
each of said guide tracks (5,6) radially outwards from the rotation
axis of said wheel, and said cam follower rollers (15) ride on these surfaces and thereby do not restrain said mold segment (10) from movement in the radially outward direction, which also has a balancing assembly for said segment (10) comprising:
a support frame (147) mounted on a fixed external support (148); a moveable carriage (146) guided from said support frame (148) carrying al least one balancing cam roller (114) positioned to exert pressure radially inwards against an annular (rack (115) integral to said segment (10) and thereby maintain each of said guide track followers (15) pressed radially against said guide track (5,6) during rotation of said wheel; and
controlled radial pressure actuation means (145) for said carriage (147) to adjust and maintain a controlled radial force of said balancing cam roller (114) against said track (115) during operation whilst allowing reciprocating annular oscillation of said segment (10).
7. A continuous casting machine as claimed in claim 5 or
claim 6 which has two or said edge guide tracks (5,6), each of which comprise opposite edges or said mold ring (93), one located ofl. either side or
the central plane of rotation of said inner-radius mold wall (8), and also having at least two of said guide track followers (15) for each of said guide tracks (5,6).
8. A continuous casting machine substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Documents:

1834-del-1996-abstract.pdf

1834-del-1996-claims.pdf

1834-del-1996-correspondence-others.pdf

1834-del-1996-correspondence-po.pdf

1834-del-1996-description (complete).pdf

1834-del-1996-drawings.pdf

1834-del-1996-form-1.pdf

1834-del-1996-form-19.pdf

1834-del-1996-form-2.pdf

1834-del-1996-form-4.pdf

1834-del-1996-gpa.pdf

1834-del-1996-petition-137.pdf

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Patent Number

219968

Indian Patent Application Number

1834/DEL/1996

PG Journal Number

28/2008

Publication Date

11-Jul-2008

Grant Date

15-May-2008

Date of Filing

19-Aug-1996

Name of Patentee

WILLIAM L. SHERWOOD

Applicant Address

Inventors:

#	Inventor's Name	Inventor's Address
1	WILLIAM L. SHERWOOD

PCT International Classification Number

B22D 11/06

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	419114	1995-04-10	U.S.A.