AU721235B2 - Rotary wheel casting machine - Google Patents

Description

ROTARY WHEEL CASTING MACINE. The invention relates to the continuous casting of steel and other metals and, more particularly, to an improved rotary 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 either a moving, endless metal belt pressed against the wheel rim by rollers to realize closure and synchronous peripheral motion with the wheel, or by multiple closure segments, or clamshell-style molds, spaced in abutting sectors around the entire wheel circumference and rotating with it, which are 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 a stationary closure belt, pressed in frictional contact against the wheel periphery spanning the casting arc.

Disadvantages of the endless belt include: heat from the casting warps the belt, also imparting a wrinkled and warped surface to the cast stock on the belt side of the section; return rollers are bulky and occupy useful space; a closed and sealed collector and conduit for spent belt-cooling water is difficult, if not impossible, to realize; belts require a regular schedule of replacement through wear and warpage; belts do not maintain uniform contact and pressure to hold the casting firmly against the wheel as the casting proceeds around the wheel; and maximum width of cast stock is very limited due to belt flexure and warpage. Despite these disadvantages, most commercial production machines employ a moving endless flexible metal belt to effect mold closure.

Disadvantages of segmented 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 lunging 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 static closure are incidence of sticking between the moving surface of the initially solidified stock and the stationary surface of the closure, resulting in possible skin ruptures and the like; also wear and operating problems associated with contact friction between wheel perimeter surface and the closure surface.

Casting wheels having an oscillating closure have also been proposed, for example, as described by pant publication JP-A-58205660, 30 November, 1983, in which a guide mold is oscillated in contrast with t4:/asting wheel, but lacking provision for maintaining a constant controlled clearance with the wheel AMENDED SHEET rim. High inertia is another common characteristic of prior art devices,making rapid oscillationi difficult.

A low-inertia closure assembly allowing rapid oscillation, in combination with close clearance control, is lacking in the prior art. 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 the 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 the prior art of rotary wheel casters.

It is a principal object of this invention to provide a rotary wheel continuous casting machine which does not have the disadvantages cited above for prior art casting wheels.

Another object is to provide a casting machine which realizes a much higher output per strand of equivalent cross-section than do conventional vertical, curved or horizontal 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 the 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 rate.

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- 1 Rihnld sector comprising at least one rigid mold segment, incorporating an outer-radius mold wall having f 30 two outer mold-wall edges which are parallel to, and interface with, said inner mold-wall Y 4T 0 AMENDED SHEET WO 98/03286 PCTF/ICA9I 00473c- edges forming a casting mold envclopc--43 between said inner -()and outer-radius (4-)mold walls; molten metal pouring means adapted for introducing molten metal proximate the entry cnd-4.)-of said mold envelope 443) 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 f(2)of said mold envelope external support means of said segmcnt-+-4)adapted to maintain it in a substantially fixed angular position in relation to said wheel; reciprocal oscillation means connected to said scgmcnt-(-)-adaptcd to effect relative annular oscillation movement of said outer radius mold wall-fl-alternately in said casting and reverse directions in relation to said support means and thereby between said outer-radius mold wall f124 and said solidifying cast section, the invention comprising combination of these with: at least one annular outer-radius mold-wall edge guide track-;---intcgral to said rotary wheel proximate the wheel rim and which is parallel to said parallel mold-wall edges-(9-,2); and at least one guide track follower fixed to said non-rotating segmcnt+-O)which is maintained in contact with said guide track-5-6)during rotation of said wheel, adapted to maintain a substantially constant dimensional clearance between said inner-radius49)-and outer-radius -(+2)-mold-wall edges.

A preferred embodiment includes two of said guide tracks4-(54), one located on either side of the central plane of rotation of said inner-radius mold wall-)- and at least two of said followers-(4-4-for each of said guide tracks-(;*, and said followers comprise cam roller followers-(w-)-which run in contact with said track-(4)-and incorporate means of restraining relative movement in the axial as well as radial direction of said cam roller followers-.(l-rclative to said track and thereby between said inncr-9)-and outer-(l-).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-(l-ride on these surfaces and thereby do not restrain said casting-mold segments44)-from movement in the radially outward direction. In one embodiment, the wheel carries anotherannular balancing guide track-(4).with faces directed radially inwards, complementary to each outward-facing track-(~-, against which rides at least one balancing cam follower-27--attached to said non-rotating casting-mold segmcnt-4).thereby maintaining contact between said guide track followers.4.-5and said guide trackf-(4)-by radially restraining movement of said casting mold segment44)-in the direction radially outwards from said wheel. In another embodiment, the casting mold segmcns-(4-S also carry a supplemenuuy guide track-(-441) against which fluid-pressure loaded balancing cam followers-(444).maintain continuous pressure and contact of the guide track followers-(-14against the wheel rim, with the balancing followers -444) in turn, being supported and positioned from a fixed support of the machine housing, or the like. The supplementary -track preferably includes a reverse capturing flange.(l44-6for the balancing follower, enabling the casting SA-DED SHE AMEN-DED S HEE WO 98/03286 PCTJCA900473..

S* S n'or.. segments to be lifted off the wheel and held in suspension during inspection or maintenance.

Mold segments-(t)- most suitably comprises a rigid; semicircular enclosure having two box side walls-(l3), a box outer cover wall-(443)-and a box inner wall carrying said outer-radius mold wall-(--on its face, in which said external support means and said oscillation means are attached to the segment-(tthereby being adapted to oscillate said outer-radius mold wall back and forth in the circumferential direction about a substantially fixed angular location on the casting wheel periphery. Spray nozzles-(3)are suitably contained within said enclosure directed radially inwards, to spray coolant directly against said outer-radius mold walls---2-and spent coolant is confined within the enclosure and discharged via an appropriate outlet duct-(40). Alternatively, the enclosure may form a pressurized water jacket, internally baffled to provide an annulus for flow of pressurized coolant against the outside of mold-wall2-)-- Appropriately, there are four studded cam roller track followers with two mounted to project outwardly from each box side wall-(-3)of segment and two balancing cam roller assemblies, one mounted on the outside of each side wall-(-4of segmcnt-(4-)-intermcdiate between said track followers including means for applying a continuous controlled pressure of the balancing rollers-(7)-against the tracks-(25 sufficient to maintain the guide track followcrs-(44)-in continuous contact with the outward-facing guide tracks-(f56- Another aspect of the invention provides a containment-roller sector-(248)adjoining the mold envelope exit end similar to the casting mold sector-14 but carrying transverse containment idler rollers-(49)-journalled in bearings4-(32 supported by the segment side walls-(1)-, 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-(4r the tangential component of this pressure acting to exert a circumferential forward propelling force on the section in the casting direction.

Means are provided for controlling the radial movement and pressure of these rollers-4 against the face of the section being cast.

Other aspects of the 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 (46)of the outer mold-wall at the entry end (42)-of the mold envelope to provide improved access for introducing liquid metal; a mold c!c:rce guiding arrangement app!icable to spray-cooled solid-bcck copper casting wheel mold rings and a universal hinge coupling assembly-(4-0).connecting adjoining segments which allows each individual to track independently on the wheel rim, without coupling backlash.

Various other objects, features and advantages of the process and apparatus of this invention will -4- AMENDED

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WO 98/03286 PCT/CA96/00473 become apparent from the following detailed description and claims, and by referring to the accompanying drawings, in which: Fig. 1 is an illustrative side view of a rotary wheel casting machine embodiment according to the 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 and 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 top view along plane 9-9 of Fig. 8 Figs. 10, and 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 segment assembly; Fig. 16 is a section view along plane 16-16 of Fig. Fig. 17A is a section view along plane 17A of Fig. Fig. 17B is a section view along plane 17B of Fig. 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; WO 98/03286 PCT/CA96/00473 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. Fig. 27 is a section view along plane 27-27 of Fig. 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 journalled 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 a solid-disc body 2 with radial stiffener ribs 19 spanning between hub 1 and U-shaped wheel rim 24, also defining cooling water jacket annulus 4. A typical wheel size would be 2-4 meters in diameter, although a wide range of sizes are possible. It is to be appreciated that a substantial part of the drawings are 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 hub assembly 1, supplied to and returned from wheel rim 24 via appropriate wheel mounted water pipes The details of this aspect and numerous other features of the wheel casting machine are 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 outerradius mold-wall edge guide tracks 5, 6 comprising cylindrical radial surfaces, directed radially outward, one on either 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 are tapered to diverge transversely outwards, for example, at a slope of I 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 In the 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 WO 98/03286 PCT/CA96/00473 segment 10, in turn, has four cam track 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, to 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 to the 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 are also provided with flanges 22 to ride against circumferential transverse alignment guide surfaces 23, incorporated into guide tracks 5,6 to maintain transverse (side-to-side) outer mold-wall alignment. Segment-mounted radially-slidable brackets, or the like, of course may be employed to augment, or as alternatives to, the eccentric bushings 16 for adjustment of track follower position and thereby clearance 17. Outer-radius mold wall 12 may be transversely contoured, for example, recessed between the edges to provide a rounded billet comer 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 with guide tracks 5, 6 during the course of rotation and application of pressure from the section being cast, the inner mold-wall support rings 3 also include a second set of annular balancing guide tracks 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 to each hinged mold segment 10, each set counteracting the corresponding two sets of rollers 15, leveraged to apply approximately equal force to each set. The rollers 27 are mounted on balancing slide arm 29, guided for movement in the radial direction only within support ring side bracket 30, and stroked by balancing cylinder 31. Such balancing actuators can be powered by any appropriate fluid, but compressible gases such as air have a clear advantage when in a pressure-control mode of this application, by compensating for wheel and track eccentricity and irregularity displacements without use of supplementary proportional or servo control valves or the like to meter fluids back and forth. Oscillation of segment 10 along the path defined by cam rollers 15 along tracks 5,6 is effected, such as by hydraulic oscillator 32 acting between rotatable bracket 33 fixed to segment 10 and externally fixed support bracket 34. A wide range of forms of hydraulic and electro-mechanical oscillators as well as casting control systems, are known in the art of continuous casting.

WO 98/03286 PCT/CA96/00473 The inner mold walls are 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 header pipe 37 feeding coolant spray nozzles 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 recirculation. 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 are conducted in essentially the same manner as a conventional flexiblebelt 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 size of the mold envelope, it will be seen that the basic machine features are 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 are 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 are confined transversely between side alignment brackets 47 of movable carriage 46, and circumferentially by the interaction between pin as fixed to carriage 46 by bracket 48, and mold side-dam oscillator bracket 49. Carriage 46 is carried on two pairs of vee-guide 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 are preferably mounted on eccentric bushings 62, providing for easy and accurate adjustment of alignment and clearance with guide track 5 1. 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 are fixed transversely by threaded take-up nuts 59 riding on support bracket WO 98/03286 PCT/CA96/00473 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 either end to drive screws 58 by couplings 57. Mold side-dam bar 44 appropriately comprises a rectangular tube 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 rapeseed 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-sealing once a continuous surface has been formed around the casting perimeter, unless stresses are 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 are 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 frozen 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 maintaining static frictional contact and pressure between the stock skin surface and the inner radius mold walls 8, as they move and propel the casting along at essentially identical surface speed. Tensional casting stress 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 are also usually superfluous. For casting wide slab sections, rollers 69 may also be split into multiple lengths incorporating intermediate segment-supported bearings.

U.

S It is obvious that minor leakage of spent cooling water can' tak6 place via clearanres 17, in the absence of sealed contact between side walls 13 and inner mold-wall edges 9. A supplementary seal may be added to minimize this leakage (not illustrated). Suitable practice could provide on the order of a meter of wheel arc, e.g. one box enclosure 10 at the top, as 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 top sector 11 need be oscillated, as an option. One or more of the containment rollers 69 may also be applied to effect thickness reduction of the cast metal section by increasing the roller pressure, optionally including liquid core reduction when the section is only partially solidified. These rollers may be undriven idlers or, alternatively, powered so as to rotate the roller surface at a rate synchronized with the surface speed of the cast metal section.

For starting of casting, a starter block or starter bar is usually inserted into the mold cavity, designed to move in unison with the wheel once casting commences. When the block can be confined between the wheel rim and containment rollers, only a relatively short starter bar is required or, alternatively, a short starter block head having a longer, flexible elastomer bar attached, which can be hollow and contoured to fit snugly in the wheel groove, in order to assist with section guidance following exit from the machine. The block characteristically includes a protruding top hook or claw designed to hold the starter block and freshly cast metal together in one piece until they areseparated following exit.

One practical difficulty in the casting of thin slab product is the desired narrow slab thickness in relation to the dimensions of submerged-entry nozzles. Figs. 8 and 9 illustrate means to mitigate this problem by a funnel-shaped departure on only the outer-radius mold wall at the nozzle 65, wherein wall 12 is extended vertically and tangentially upwards, as at 67, at right angles to the wheel horizontal center line in the plane of rotation of the wheel, at the transverse location of submerged entry nozzle 65, on either side of which mold-wall 12 is graduated into the straight-sided cylindrical wall, in the form of a half funnel-segment 68 with maximum width at the location of molten metal entry 42. In the embodiment illustrated, where the thickness of nozzle 65 is nearly equal to the casting thickness, it may be seen that adequate insertion is obtained, including good wall clearance, by vertical insertion of nozzle 65 parallel to this vertical funnel wall.

Fig. 10 illustrates a containment roller positioning and pressure-adjustment assembly 127 for transverse containment rollers 69 against the outer section surface. The roller shafts 71 are joumalled within sealed cartridge bearings 72, riding in guided chocks 73, as recessed in the structure of side-walls 13 of segment 90. The chocks 73 and thereby rollers 69 are loaded and retracted by air or hydraulic :--Dl-inders 70, through which the position or force of each roller against the cast metal section surface 104

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v o« AMENDED SHEET can be adjusted. Fig. 11 illustrates another embodiment of positioning and pressure-adjustment assembly 127 for rollers 69, whereby the outer race of bearings 72, mounted on roll shaft 83, are 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 annulus 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 sizes 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 the 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 against the outer surface 104 of the solidifying cast metal section. This arrangement facilitates close control of the 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 the variations in position of casting surface 104 as the 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 -11- AMENDED

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WO 98/03286 PCT/CA96/00473 disadvantage of unequal roller pressures or stock-to-roller 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 17B and 18 illustrate additional or alternative embodiments of the mold segment apparatus 10. This includes a pressurized 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-bolts 110 are sealed by way of an appropriate O-ring gland 113. The outer radius mold wall shoes 112 are sealed by an elastomer-coated metal gasket 130 and fastened in position by screws 131. Among other 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 an external support frame, to locate and control the force of flanged rollers 114 against balancing track 115. Rollers 114, in turn, are mounted with clearance but captured within retention flange 116, thus providing for retracting the segments radially outward and off the wheel to 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 outer radius mold wall shoes 112 after use; in comparison with replacement with new ones. Adjusting screw 122 effects adjustment of pillow blocks 121, to be held in position by locking screws 123. In order to 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 contact between 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 hingecoupling 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-nut assembly 118 and at an adjustable distance of separation between flanges 82, and also incorporating pre-load spring 119 with spring rate force sufficient to eliminate clearances and any backlash, whilst allowing both transverse and angular misalignment between segments. As applied to mold segments 10, in order to accommodate mold shoe thermal expansion in the event that adjacent mold shoe ends are closely butted together at start-up, Belleville spring-washers are appropriately inserted between the nuts and bearings 117, designed to balance the opposing force of spring 119, and with additional travel sufficient to accommodate the expansion after start-up.

0o -t i0 bo Fig. 17B also illustrates the variation of a contoured transverse pro:f-le of'outer-adiu' mold ll 112, in which side faces 18 are extended past clearance 17 into a recess of outer mold wall shoe 112. This eliminates the acute angle at the section comer entering into gap. 17 and also allows a rounded comer 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 comer, 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 comer 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 band closure casting wheels commonly used for casting copper and aluminum billets and rods normally utilize 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 tube 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 tube 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 cantilevered out from a backing frame also supporting the main casting wheel hub and bearings. Please note that piping and wiring and the like is omitted 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 motor 98 as an alternative to air motor 74 with gear box and belt drive 75, as illustrated in Fig. 19. Eccentric crank extension 99 revolves around the center axis of shaft-97 carrying connecting rod dnve bearing 105.

In order to adjust the stroke length as indicated by the graduated index 155, location ring 154 of cantilevered stub shaft 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 the mold segments.

Figs. 25, 26, 27, 28 and 29 illustrate additional or alternative embodiments of the roller segment apparatus 90. The containment roller positioning and pressure-adjustment assembly 127 comprises drive eccentric disk 137 and driven eccentric disk 138 which are equally eccentric to roller shaft 84 and keyed to it by parallel cross keys 134 and 135, as S T -13- 3,.

z.i WO 98/03286 PCT/CA96/00473 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 rotatable 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 joumalled within bearings 163 of housing 164, which is bolted 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 splined 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 stop-screw 169, as carried on bracket 168 attached to housing 164, against pin 167 which rotates integrally with shaft 162. Operated pneumatically, this provides for pressure control of roller 69 against cast metal section surface 104 during stroke extension, providing for section movements, dimensional and surface irregularities whilst maintaining effectively constant roller force. Alternatively, operating with cylinder retracted or zero extension air pressure, provides for positional containment only, even allowing the cast section to release from the wheel, according to the setting of stop-screw 169. The roller segment assembly 90 is adapted to provide combined air-water cooling via air manifold 139 and water manifold 140 feeding spray block 141 into air-most nozzles 142, as well as spray water only, onto rollers 69 via water nozzles 144. As shown, these segments are not enclosed, although they could be so arranged if desired. Segment-to-segment hinging and segment balancing assemblies are analogous to those of the mold segments 10, as illustrated.

It will be appreciated that a rotary wheel casting machine has been described and illustrated and that modifications and variations may be made by those skilled in the art, without departing from the scope of the invention defined in the appended claims.

Claims (25)

1. A continuous casting machine comprising a rotary wheel incorporating a circumferential inner-radius mold wall with two parallel annular inner mold-wall edges integral with the wheel rim; a non-rotating casting-mold sector (11) 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 forming a casting mold envelope (43) between said-inner 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 metal section, in combination with: at least one annular outer-radius mold-wall edge guide track integral with said rotary wheel proximate the wheel rim and which is parallel to said parallel mold-wall edges and at least one guide track follower (15) fixed to said segment (10) which is maintained in contact with said guide track during rotation of said wheel, adapted to maintain a substantially constant dimensional clearance between said inner-radius and outer-radius (21) mold-wall edges.

2. A continuous casting machine according to claim 1 which includes two of said edge guide tracks one located on either side of the central plane of rotation of said inner-radius mold wall and also including at least two of said guide track followers (15) for each of said guide tracks and wherein said followers comprise cam roller followers (15) adapted to run in contact with said tracks

3. A continuous casting machine according to claim 1 which includes two of said guide tracks one located on either side of the central plane of rotation of said inner-radius mold wall and also including at least two of said followers (15) for each of said guide tracks and wherein said followers comprise cam follower rollers (15) which run in contact with said tracks 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 and outer (12) mold-wall edges during wheel rotation and in which the radial guide surfaces of each said guide tracks 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 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 WO 98/03286 PCT/CA96/00473 track against which rides at least one balancing cam follower (27) attached to said segment thereby maintaining contact between said guide track followers (15) and said guide track by radially restraining movement of said segment (10) in the direction radially outwards from said wheel.

4. A continuous casting machine according to claim 1 wherein said mold segment (10) comprises a rigid, semicircular box enclosure having two side walls 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 thereby being adapted to direct coolant sprays (39) directly against said outer-radius mold wall and a coolant exit duct (40) proximate said bottom exit-end wall adapted for draining spent coolant from within said enclosure by gravity. A continuous casting machine according to claim 1 wherein said inner radius mold wall is integral with an annular casting wheel mold ring (93) and said guide track comprises the annular rim of said mold ring (93).

6. A continuous casting machine according to claim 1 wherein said inner radius mold wall is integral with an annular casting wheel mold ring (93) and said guide track comprises the annular rim of said mold ring which includes coolant sprays (159) directed to impinge radially outwards against the inside surface of said ring, adapted for removal of heat conducted radially inward through the body of said mold ring (93).

7. A continuous casting machine according to claim 1 which includes two of said guide tracks one located on either side of the central plane of rotation of said inner-radius mold wall and also including at least two of said followers (15) for each of said guide tracks and wherein said followers comprise cam follower rollers (15) which run in contact with said track 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 and outer mold-wall edges (21) during wheel rotation and in which the radial guide surfaces of each of said guide tracks 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 includes a balancing assembly for said segment (10) comprising: a support frame (147) mounted on a fixed external support (148); a movable carriage (146) guided from said support frame (148) carrying at least one balancing cam roller (114) positioned to exert pressure radially inwards against an annular track (115) integral to said segment and thereby maintain each of said guide track followers (15) pressed radially against said guide track during rotation of said wheel; and controlled radial pressure actuation means (145) for said carriage (147) adapted to adjust and maintain a -16- WO 98/03286 PCUCA96/00473 controlled radial force of said balancing cam roller (114) against said track (115) during operation whilst allowing reciprocating annular oscillation of said segment

8. A continuous casting machine according to claim 5 or claim 6 which includes two of said edge guide tracks each of which comprise opposite edges of said mold ring one located on either side of the central plane of rotation of said inner-radius mold wall and also including at least two of said guide track followers (15) for each of said guide tracks

9. A continuous casting machine according to claim 5 or claim 6, which includes two of said edge guide tracks each of which comprise opposite edges of said mold ring one located on either side of the central plane of rotation of said inner-radius mold wall, and also including at least two of said followers (15) for each of said guide tracks, and wherein said followers comprise cam follower rollers which run in contact with said track 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 and outer (21) mold-wall edges during wheel rotation and in which the radial guide surfaces of each said guide track face radially outwards from the rotation axis of said wheel, and said cam follower rollers ride on these surfaces and thereby do not restrain said mold segments (10) from movement in the radially outward direction, in combination with: external radial balancing means acting from a fixed support external to said wheel, adapted to maintain contact between said guide track followers (15) and said guide track by radially restraining movement of said casting mold segment (10) in the direction radially outwards from said wheel.

10. A continuous casting machine according to claim 1, 2, 3,4, 5, 6, or claim 7, wherein said mold segment (10) comprises a rigid, semicircular enclosure having two side walls an outer cover wall (143) and an inner wall carrying said outer-radius mold wall (12) on its inner radius, and in which said external support means and said oscillation means is attached to said enclosure (10) by way of said oscillation means, which is thereby 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.

11. A continuous casting machine according to claim 1, 2, 3, 4, 5, 6, or claim 7, wherein said mold segment (10) comprises a rigid, semicircular enclosure having two side walls an outer cover wall (143) and an inner wall carrying said outer-radius mold wall (12) on its inner radius, and in which said external support means and said oscillation means is attached to said enclosure (10) by way of said oscillation means, which is thereby 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; and fluid coolant spray nozzles (38) contained within said enclosure directed radially inwards, and means for supply of pressurized coolant to said nozzles adapted to direct coolant sprays (39) directly against said outer-radius mold walls. WO 98/03286 PCUCA96/00473

12. A continuous casting machine according to claim 1 carrying a radially outward-facing edge guide track and a radially inward-facing balancing guide track (25) on either side axially of said wheel rim, each parallel to said annular mold wall edges and wherein the mold segment (10) comprises a rigid enclosure having two side walls an outer cover wall (143) carrying said outer-radius mold wall (12) on its inner radius; four studded cam roller track followers two of which are mounted to project outwardly from one said enclosure side wall, one on either side of the transverse center line of said mold segment and two corresponding roller followers (15) mounted on the opposite side wall, to run in contact with said outwardly-facing guide tracks and respectively, two balancing cam roller assemblies, one mounted on the outside of each of said enclosure sidewalls, intermediate between said track followers comprising a follower roller (27) supported from said box enclosure and riding in contact with said inward-facing track with means for applying a continuous controlled pressure of said balancing follower roller (27) against said track sufficient to maintain said four cam roller track followers in continuous contact with said outward-facing guide track during wheel rotation.

13. A continuous casting machine according to claim 12 wherein said means for applying a continuous controlled pressure of said balancing follower roller (27) against said balancing guide track comprises a fluid-pressurized cylinder (31) mounted on a bracket (30) projecting axially from the side wall of said enclosure, having the cylinder rod projecting radially inwards and the cylinder rod end carrying said balancing follower roller (27) with its axis at right angles to the cylinder axis, thereby being adapted to apply a continuous and controlled force of said balancing roller (27) against said inward- facing balancing guide track

14. A continuous casting machine according to claim 12 wherein said cam roller guide track followers include a circumferential radially-projecting flange (22) adapted to abut a circumferential transverse alignment guide surface integral said wheel rim and also parallel to said mold-wall edges thereby maintaining substantially constant transverse alignment between said enclosure and said wheel rim. A continuous casting machine according to claim 12 wherein said non-rotating casting mold sector (11) comprises a plurality of said mold segments (10) abutting end-wise, hinged together to present a substantially continuous outer mold wall (12) from said entry end (42) to said exit end

16. A continuous casting machine according to claim 1, 2, 3, 4, 5, 6 or claim 7, which also includes a non-rotating containment-roller sector (28) comprising at least one roller segment (90) adjoining said exit end of said mold envelope from which exits the partially solidified cast metal section, said roller segment (90) comprising two side walls (13) with inner edges parallel and adjacent to said wheel rim, with inner wall open into the casting mold envelope (43) bounded by said inner-radius mold wall and side faces a plurality of guide track followers (15) mounted on said side-walls and maintained in contact with said edge guide tracks adapted to maintain a substantially constant dimensional WO 98/03286 PCT/CA96/00473 clearance between said inner edges of said side walls (13) and the wheel rim; transverse containment idler rollers (69) journalled in bearings (72) supported by said side walls (13), with faces positioned and adapted to press radially inwards against the outer face of said cast metal section to maintain the inner face of said section pressed against said inner-radius mold wall the tangential component of this pressure acting to exert a circumferential forward propelling force on said section in said casting direction; and fluid cooling means for the outer face of said cast metal section.

17. A continuous casting machine according to claim 1, 2, 3, 4, 5, 6 or claim 7, which also includes a non-rotating containment-roller sector (28) comprising at least one roller segment (90) adjoining said exit end (20) of said mold envelope from which exits the partially solidified cast metal section, said roller segment (90) comprising two side walls with inner edges parallel and adjacent to said wheel rim, with inner wall open into the casting mold envelope (43) bounded by said inner-radius mold wall and side faces a plurality of guide track followers (15) mounted on said side-walls and maintained in contact with said edge guide tracks adapted to maintain a substantially constant dimensional clearance between said inner edges of said side walls (13) and the wheel rim; transverse containment idler rollers (69) journalled in bearings (72) supported by the side walls of said roller segment (90) with faces positioned and adapted to press radially inwards against the outer face of said cast metal section to maintain the inner face of said section pressed against said inner-radius mold wall the tangential component of this pressure acting to exert a circumferential forward propelling force on said section in said casting direction; an outside cover wall (143) of said containment roller segment coolant spray nozzles (38) contained within said cover-wall directed radially inwards, and means for pressurized liquid coolant supply to said nozzles adapted to direct liquid coolant sprays (39) directly against said outer face of said cast metal section; and at least one discharge duct (40) for spent coolant from within said roller box enclosure (90) proximate its lower extremity.

18. A continuous casting machine according to claim 1, 2, 3, 4, 5, 6, or claim 7, which also includes a sector (28) comprising at least one roller segment (90) adjoining said exit end (20) of said mold envelope from which exits the partially solidified cast metal section, said roller segment (90) comprising two side walls (13) with inner edges parallel and adjacent to said wheel rim, with inner wall open into the casting mold envelope (43) bounded by said inner-radius mold wall and side faces (18), a plurality of guide track followers (15) mounted on said side-walls, and maintained in contact with said edge guide tracks adapted to maintain a substantially constant dimensional clearance between said inner edges of said side walls and the wheel rim; transverse containment idler rollers (69) journalled in bearings (72) supported by said side walls (13), -19- WO 98/03286 PTC9/07 PCT/CA96/00473 with faces positioned and adapted to press radially inwards against the outer face of said cast metal section; containment roller positioning means adapted to move said containment idler rollers (69) in direction towards and away from contact with said outer face of said section; and containment roller pressure-adjustment means adapted for controlled adjustment of the amount of force exerted by said containment rollers (69) against said cast metal section upon contact with said section, as required to maintain non-sliding frictional contact between the inner face of said section pressed against said inner-radius mold wall the tangential component of this pressure acting to exert a circumferential forward propelling force upon said section in the casting direction.

19. A continuous casting machine according to claim 1, 2, 3, 4, 5, 6, or claim 7, in which said entry end (42) and exit end (20) of said mold envelope (43) are respectively above and below the horizontal center line (80) in the plane of rotation of said wheel, wherein a portion of said outer-radius mold wall (12) extends substantially tangentially and vertically upwards from a point proximate said horizontal center line (80) extending to said entry end creating a funnel-shaped entrance into said mold envelope (43), adapted to provide increased clearance for the vertical insertion, juxtaposed with said outer-radius mold wall of a submerged entiy nozzle (65) from a position above said non-rotating casting mold sector (11). A continuous casting machine according to claim 1, 2, 3, 4, 5, 6, or claim 7, in which said casting mold envelope (43) has a rectangular cross section with longitudinal axis parallel to the axis of said rotary wheel adapted for casting of metal slab sections, which also includes two semicircular side-dam bars (44) inserted into said mold envelope (43) from said entry end spanning between said inner (8) and outer-radius (12) mold walls, adapted to transversely confine the sides of said molten metal and partially solidified cast metal section within said mold envelope also including means for width- adjustment of the transverse distance of separation between said side-dam bars (44) and thereby the width of said metal section. 2 1. A continuous casting machine according to claim 1 in which said casting mold envelope (43) has a rectangular cross section with longitudinal axis parallel to the axis of said rotary wheel adapted for casting of metal slab sections, which also includes two semicircular side-dam bars (44) inserted into said mold envelope (43) from said entry end spanning between said inner (18) and outer-radius (12) mold walls, adapted to transversely confine the sides of said molten metal and partially solidified cast metal section within said mold envelope also including means for adjustment of the transverse distance of separation between said side-dam bars (44) and thereby the width of said cast metal section, which includes: a transverse guide track fixed (5 1) to said non-rotating casting mold segment (11); two movable carriages (46) supported on guide followers (53) which run on said transverse guide track support means for said side-dam bars (44) upon each of said carriages (46) proximate the entry end (42) of said mold envelope; and means for transverse positioning of said carriages (46) along said guide track (5 thereby being adapted for adjusting the distance of separation between said two side-dam bars (44) according to the required width of said cast metal section.

22. A continuous casting machine according to claim 21 wherein said support means for said side-dam bar (44) comprises side alignment brackets (47) between which the side faces of said side-dam bars (44) are slidably confined; a slotted hinge connection (48, 49, 50) incorporating a slot allowing bracket self-centering movement in the radial direction, whilst preventing relative movement between said carriage (46) and side-dam bar (44) in the circumferential direction, thereby being adapted to oscillate each of said side-dam bars (44) circumferentially in unison with said carriage (46) and non-rotating casting mold segment whilst allowing for radial self-alignment of said side-dam bar (44) within said mold envelope.

23. A 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 (12) having two outer mold-wall edges (21) which are parallel to, and interface with, said inner mold-wall edges forming a casting mold envelope (43) confined 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 dhe 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); at least two annular guide tracks mounted proximate the wheel rim and rotating with the wheel, one track located on either side of the plane of rotation of said inner-radius mold wall a non-rotating containment-roller sector (28) comprising at least one roller segment (90) adjoining said exit end (20) of said mold envelope from which exits the partially solidified cast metal section, said roller segment (28) comprising at least one rigid semi-circular containment-roller segment (90) having two side walls (13) with inner edges parallel and adjacent to said wheel rim, with inner wall open into the casting mold envelope (43) bounded by said inner-radius mold wall and side faces (18); a plurality of guide track followers (15) mounted on each of said side-walls which run in contact with said guide tracks adapted to hold said containment roller segment (28) in a substantially fixed radial position relative to said wheel rim and maintain a substantially constant dimensional clearance between said inner edges of said box side walls (13) and the rotating wheel rim; transverse containment rollers (69) supported by said side walls with faces positioned and if -21- (i J- i^ SHEET o .s t dl d a 1 .oo adapted to press radially inwards against the outer face of said cast meial section; containment roller positioning and pressure-adjustment assembly (127) adapted to move said rollers (69) in direction towards and away from contact with said outer face of said sections and effect controlled adjustment of the amount of force exerted by said containment rollers (69) against said cast metal section upon contact with said section, as required to maintain non-sliding frictional contact between the inner face of said section pressed against said inner-radius mold wall the tangential component of this pressure acting to exert a circumferential forward propelling force upon said section in the casting direction.

24. A continuous casting machine according to claim 23 also comprising an outside cover wall (143) of said containment segment coolant spray nozzles (38) contained within said cover-wall (143) directed radially inwards, and means for pressurized liquid coolant supply to said nozzles adapted to spray liquid coolant directly against said outer face of said cast metal section; and at least one discharge duct for spent coolant from within said roller box enclosure proximate its lower extremity

25. A continuous casting machine according to claim 23 or claim 24, wherein said containment idler rollers (69) are fixed to a shaft (83) coaxial with said rollers said shaft (83) carrying bearings (72) joumalled within circular bushings (76) journalled, in turn, within each of said side walls with a common axis of said bushings (76) eccentric to the axis of said shaft and wherein said positioning means comprises actuator means adapted for rotary angular displacement of said bushings (76).

26. A continuous casting machine according to claim 23 or claim 24, wherein said containment idler rollers (69) are mounted on bearings (72) adapted for rotation about a shaft (84) co-axial with said rollers said shaft (84) carrying rotationally fixed circular bushings (85) journalled within each of said side walls with a common axis of said bushings (85) eccentric to the axis of said shaft and wherein said positioning means comprises an actuator adapted for rotary angular displacement of said shaft (84); and said pressure-adjustment means comprises actuator means (91) adapted for controlling the torque affecting angular displacement of said shaft (84).

27. A continuous casting machine according to claim 23 or claim 24, wherein said containment idler rollers (69) are mounted on bearings (72) for rotation about a shaft (84) coaxial with said rollers and said bearings (72) are carried by chocks (73) adapted for movement in the radial direction within parallel surfaces integral to said segment side walls and wherein said positioning means comprises fluid pressurized cylinders (70) with rods connected to said chocks (73) to stroke in the radial direction, said cylinders (70) being integrally mounted upon said segment and said pressure-adjustment assembly includes controlled changing of the fluid pressure within said cylinders -22- D SHEET WO 98/03286 PTC9107 PCT/CA96/00473

28. A continuous casting machine according to claim 7 wherein said non-rotating sector (11) includes at least one capture member of said balancing follower roller (114) limiting its free movement radially outwards; and radial withdrawal means of said carriage (146) and thereby of said segment (11) for holding in a position clear of said wheel adapted for carrying out inspection and maintenance.

29. A continuous casting machine according to claim 1, 2, 3, 4, 5, 6 or claim 7 wherein said entry end (42) of said mold envelope (43) includes a metal overflow channel (149) proximate the axial plane of said wheel having the entry invert of said channel at an elevation lower than the highest junction between the entry ends (42) of said inner-radius and outer-radius (12) mold walls. A continuous casting machine according to claim 1,2, 3, 4, 5, 6, 16, 17, 18, 19 or 20 which comprises at least two segments (10, 90) wherein adjacent segments are connected together by a universal hinge coupling assembly (120) proximate the central plane of said wheel, said assembly (120) comprising: two externally-restraining spherical thrust bearings (117) abutting flanges (82) carried by each respective enclosure (10, 90) thereby linmiting separation distance between said flanges (82); and adjustable length bolt assembly (118) limiting separation distance between said thrust bearings (117); and a compression pre-loading spring (119) between said flanges (82) adapted for maintaining pressurized contact between the mating faces of said thrust bearing (117) and between said bearing (117) and said flanges (82) during operation. 3 1. A continuous casting machine according to claim 2, 3, 4, 5, 6, or claim 7, which includes two of said edge guide tracks one located on either side of the central plane of rotation of said inner-radius mold wall and also including at least four cam follower rollers (15) mounted in axially opposite pairs and adapted to press axially against said guide tracks which includes an axial spring means axially pre-loading one roller of each pair of said followers thereby being adapted to eliminate axial clearance and prevent yawing or vibration of segments (10) during oscillation.