EP0912273A1 - Permanent-magnetic hydrodynamic methods and apparatus for stabilizing continuous casting belts - Google Patents
Permanent-magnetic hydrodynamic methods and apparatus for stabilizing continuous casting beltsInfo
- Publication number
- EP0912273A1 EP0912273A1 EP97934873A EP97934873A EP0912273A1 EP 0912273 A1 EP0912273 A1 EP 0912273A1 EP 97934873 A EP97934873 A EP 97934873A EP 97934873 A EP97934873 A EP 97934873A EP 0912273 A1 EP0912273 A1 EP 0912273A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- pole
- casting belt
- elongated
- belt
- magnetic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
- B22D11/0637—Accessories therefor
- B22D11/0677—Accessories therefor for guiding, supporting or tensioning the casting belts
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
- B22D11/0637—Accessories therefor
- B22D11/068—Accessories therefor for cooling the cast product during its passage through the mould surfaces
- B22D11/0685—Accessories therefor for cooling the cast product during its passage through the mould surfaces by cooling the casting belts
Definitions
- the present invention is in the field of continuous casting of molten metal by pouring it into belt-type casting machines using one or more endless, flexible, moving heat-conducting casting belts, e.g., metallic casting belts, for defining a moving mold cavity or mold space along which the belt or belts are continuously moving with successive areas of each belt entering the mold cavity, moving along the mold cavity and subsequently leaving the moving mold cavity.
- the product of such continuous casting is normally a continuous slab, plate, sheet or strip or a generally rectangular continuous bar.
- this invention relates to permanent-magnetic hydrodynamic methods and apparatus for stabilizing a moving, flexible, thin-gauge, heat-conducting, magnetically soft ferromagnetic casting belt against thermal distortion while it is moving along the mold cavity being heated at its front surface by heat coming from molten metal while being cooled at its reverse surface by flowing pumped liquid coolant.
- Hazelett et al. in U.S. Patents 3,937,270; 4,002,197; 4,062,235; and 4,082,101 in FIG. 8 of each Patent and Allyn et al. in FIG. 5 of U.S. Patent 4,749,027 illustrate thermally-induced transverse bucking and fluting occurring in such a casting belt. Thermally-induced warping or wrinkling also has occurred in such belts. These belt distortions can occur quite suddenly, like a sudden popping of a lid on an evacuated container when the lid initially is opened and air rushes into the container. Moreover, these distortions can be erratic and unpredictable as to their extent and their particular locations in a casting belt which is intended to be even, without distortions, as it moves along the mold cavity.
- Such thermally-induced distortions are more likely to occur near an input region of the mold cavity where the moving casting belt first experiences intense heating effects of hot molten metal introduced into or soon after its introduction into the moving mold cavity.
- Near the input region initial freezing of molten metal is occurring or commencing, and belt distortions during such freezing may result in a cast product containing slivers, stains or segregation of alloying constituents.
- these defects in the cast product lead to problems of strength, formability, and appearance.
- each cooling assembly comprised a plate that may be of some suitable readily magnetized material which formed the soft core of an electromagnet. It was the function of a plate when rendered magnetic by flow of current to pull a band toward itself. To prevent this movement of the band toward the plate, copper or brass spacers were utilized, these spacers allowing a formation of chambers between the band and the plate. In these chambers cooling water was introduced to chill the band.
- this reach-out pull is provided by the unique permanent-magnetic materials described herein arranged in magnetic circuits as described for reaching out across spacings (gaps) between pole faces of the magnetic circuits and a moving, flexible, thin-gauge, heat-conducting casting belt of magnetically soft ferromagnetic material for pulling thermally distorting portions of the belt toward the pole faces for keeping the belt held within close limits in a predetermined desired stabilized even condition where it is supported by hydrodynamic forces provided by flows of pumped coolant as explained later such that the stabilized belt is moving along its predetermined path while hovering in stabilized even condition levitated by hydrodynamic repulsive forces exerted by pumped liquid coolant and fast-travelling coolant films, and the belt is not sliding nor wearing against stationary objects but moves along water films substantially without friction.
- a plurality of hydro-magnetic devices arranged in arrays wherein flows of pumped liquid coolant pass through fixedly throttling passageways leading into pressure pockets acting as throttling nozzles facing the casting belt's reverse surface.
- These coolant flows are issued from these throttling nozzles which are adjacent to or are rimmed by the magnetic pole faces for exerting repulsive forces against the reverse surface of the belt with coolant escaping (ejecting) from the pressure pockets in the form of fast-moving films of liquid coolant radiating from the pressure pockets and travelling in the gaps between the reverse surface of the moving casting belt and the magnetic pole faces.
- the hydro-magnetic devices in these arrays include powerful permanent magnets formed of unique permanent-magnetic material. These magnets positioned in magnetic circuits in each array provide reach-out magnetic attraction forces having unusual characteristics which we believe are critical to successful operation of the disclosed embodiments of the invention.
- the unusual very powerful magnetomotive force provided by such permanent magnets (which have a very high maximum energy product expressed in Mega-Gauss-Oersteds) is not the sole reason in our view for their successful operation in magnetic circuits employed in these arrays or "pillows" of hydro-magnetic devices.
- Another characteristic which we believe is critical for their successful operation is their very low demagnetizing permeability which is so low it is of the same order of magnitude as that of air or water or vacuum.
- This very low demagnetizing permeability enables pole faces and poles of magnetic circuits as disclosed to exert very powerful magnetic attraction forces (pulling forces) on a moving, flexible, thin-gauge, heat-conducting casting belt containing magnetically soft ferromagnetic material with such attraction forces extending out (reaching out) relatively far away from the pole faces and extending across gaps (spacings) between the pole faces and the moving casting belt with air and/or water filling these spacings.
- These magnets in their magnetic circuits provide an array of coplanar magnetic pole faces of alternate North and South polarity facing toward the reverse surface of a moving, flexible, thin-gauge, heat-conducting casting belt containing magnetically soft ferromagnetic material.
- These repulsive forces diminish relatively rapidly as a function of increasing spacing (increasing gap) between the reverse surface of the belt and a magnetic pole face over which the fast-travelling coolant films are flowing.
- These repulsive forces are balanced against the reach-out attraction force (pull) exerted on the moving belt by the pole face in the same location, which attraction force diminishes relatively more slowly as a function of such increasing spacing.
- hydro-magnetic devices are incorporated specially devised sweep nozzles for delivering additional coolant applied to the belt at an acute angle to result in a sheet of fast-moving coolant flowing in one direction along the reverse surface of the belt providing additional cooling as well as diverting, redirecting and finally sweeping away the fast travelling coolant films which have passed over the magnetic pole faces.
- the moving belt is stabilized with predetermined desired evenness or flatness by balancing this reach-out pull against hydrodynamic forces of pumped liquid coolant issuing from throttling nozzles in the hydro-magnetic devices and exerting a push against the reverse surface of the moving belt at locations closely adjacent to the magnetic pole faces for keeping the moving belt stabilized in a hovering (levitated) relationship spaced away from contact with the pole faces.
- This powerful reach-out attraction force (pull) on a thin-gauge belt of magnetically soft ferromagnetic material is unlike the behavior of magnets made of traditional materials, even alnico 5, which materials lose much of their attraction force or pull when significant gaps, for example such as gaps of 1.5 mm (0.060 of an inch) occur in magnetic circuits such as shown and described.
- any permanent magnetic material is capable of successful performance in embodiments of the invention, if such material is capable of being mounted as permanent magnets in magnetic circuits including magnetically soft ferromagnetic material providing an array of magnetic poles of opposite polarity having pole faces faceable toward the reverse surface of a moving casting belt with such pole faces being immediately adjacent to throttling nozzles (for example with such pole faces rimming or encircling the throttling nozzles) , such nozzles being faceable toward the reverse surface of the casting belt and wherein such pole faces and pole members are capable of exerting reach-out magnetic attraction forces (pull) on a moving, flexible, thin-gauge, heat-conducting casting belt containing magnetically soft ferromagnetic material wherein this reach-out magnetic attraction is sufficiently powerful at an initial value at the pole faces and wherein this reach-out magnetic attraction exerted on the casting belt near the arrays diminishes from its initial value sufficiently slowly as a function of increasing spacing up to 1.5 mm (0.060 of an inch) gap between the portion
- Rotating devices may be provided for rotating the permanent magnets in order to reduce, whenever desired, their powerful reach-out pull on the belt, with sufficient reduction in pull to permit installing and removing wide thin-gauge flexible casting belts without damage to them.
- magnetic flux from the powerful magnets may be shunted away from the casting belt by a suitably movable shunt to reduce pull on the belt sufficiently to permit appropriate handling of the belt.
- the present invention successfully addresses or substantially overcomes or substantially reduces the above-mentioned persistent problems caused by thermally induced distortions of a moving, endless, flexible, thin-gauge, heat-conducting casting belt in a continuous casting machine.
- the term "thin-gauge" as applied to a heat-conducting casting belt formed predominantly of steel is intended to mean a casting belt having a thickness less than about one-tenth of an inch (about 2.5 mm) and usually less than about 0.070 of an inch (about 2.0 mm) .
- Magnetic permeability of magnetically soft ferromagnetic material is defined as B/H wherein "B” is magnetic flux density in Gauss in a material and “H” is magnetic coercive force in Oersteds applied to the material.
- the term "magnetically soft ferromagnetic material” means a material which has a maximum magnetic permeability of at least about 500 times the magnetic permeability of air or water or vacuum, each of which has a magnetic permeability of about 1.
- ordinary transformer steel has a maximum magnetic permeability of about 5,450 as measured at a magnetic flux density B of about 6,000 Gauss with a magnetic coercive force H of about 1.1 Oersted, stated on page E-115 of the CRC Handbook of Chemistry and Physics.
- magnetically soft as used in this term "magnetically soft ferromagnetic material” means that such material is relatively easily magnetized or demagnetized.
- soft is herein being used in contradistinction to the adjective “hard” which is applied to magnetic materials requiring a large coercive force to become magnetized or demagnetized such that they are difficult to magnetize and demagnetize.
- Ordinary transformer steel and also the quarter-hard-rolled low-carbon sheet steel usually employed in forming thin-gauge casting belts for use in twin-belt continuous casting machines are within the category of "magnetically soft ferromagnetic material".
- the permeability of a hard magnetic material is ⁇ B/ ⁇ H as measured in a useful portion of the demagnetization curve, which curve is in turn defined as that portion of the B-H hysteresis loop, i.e., the B-H loop or B-H curve, lying in the second (or fourth) quadrant of the normal hysteresis loop.
- "Normal hysteresis loop" is defined in the above ASTM Designation.
- FIG. 1 is a perspective view of a twin-belt casting machine as seen looking from upstream, above, and from the outboard side. This machine is shown as an illustrative example of a relatively wide, moderately-thin-gauge-belt-type continuous metal-casting machine in which the present invention may be employed to advantage.
- FIG. 2 is an enlarged partial perspective view showing an array of hydro-magnetic devices in an embodiment of this invention as positioned in the lower carriage and as seen from above and downstream.
- the moving flexible casting belt is partially shown broken away in FIG. 2 for clarity of illustration.
- FIG. 2 is a view as seen looking generally in the direction II-II in FIG. 3 and also in FIGS. 4 and 4A.
- FIG. 3 is a top view of an array of the hydro-magnetic devices, three of which are shown in FIG. 2.
- the casting belt and its pulley drums are omitted for clear illustration.
- FIG. 3A is a close-up view of a portion of FIG. 3 revealing schematically the flows of liquid coolant against the lower reverse surface of the unshown lower casting belt.
- FIG. 4 is an elevational longitudinal sectional view as seen from the outboard side of the machine showing a typical hydro-magnetic device or sub-assembly of a hydro-magnetic pillow or array as it appears surrounded by other elements of the lower carriage of a belt-type casting machine such as shown in FIG. 1.
- the moving edge dams of the casting machine are shown in FIG. 1 and are not shown in FIG. 4 for clear illustration.
- FIG. 4A is similar to FIG. 4 but shows a configuration of a hydro-magnetic device for cooperative interaction with an upstream nip pulley drum, also called a nip pulley roll.
- FIG. 4B shows an enlargement of a portion of FIG. 4A for illustrating a modified embodiment of the invention including a flat, downstream-aimed, "afterburner” coolant sweep nozzle.
- FIG. 4C is an enlargement of a portion of FIG. 2 for showing the "afterburner" sweep nozzle seen in FIG. 4B.
- FIG. 5 is a partial elevational view combined with partial cross-sectional views of apparatus within the lower carriage of a casting machine embodying the present invention as seen from upstream looking downstream.
- the three respective zones marked VA, VB and VC are the areas identified by the respective viewing lines VA-VA, VB-VB and VC-VC in FIG. 4A.
- FIG. 6 is an enlarged view of a portion of FIG. 5, showing a typical magnetic circuit with thin, fast-travelling coolant-films passing through gaps between pole faces and the reverse surface of a moving casting belt.
- the relative thickness of the coolant-film gap is here exaggerated for clarity of illustration.
- FIG. 7 shows plots illustrating equilibrium balancing or stabilization of a moving casting belt as a function of gap spacings between the moving casting belt and the magnet-nozzle pole faces (rims of the coolant pressure pockets) .
- FIG. 7 illustrates pull/push balancing between: (i) the relatively slowly decreasing reach-out magnetic attraction forces which may be called inward pulling forces and (ii) the relatively rapidly decreasing repulsive hydrodynamic forces of the pumped liquid coolant and high-speed thin coolant films which may be called outward pushing forces.
- the relatively rapid and undesirable decrease of attraction force provided by alnico 5 magnets is shown.
- FIG. 7A is like the left portion of FIG. 7 but with the horizontal scale expanded about 6 to 1.
- FIGS. 7A* and 7A" are included for purposes of explanation.
- FIG. 8 is a longitudinal sectional elevation view as seen from the outboard side of the moving mold-cavity region of the carriages showing arrays of hydro-magnetic devices, that is hydro-magnetic pillows, positioned in respective places along the length of the moving mold cavity.
- arrays of hydro-magnetic devices that is hydro-magnetic pillows, positioned in respective places along the length of the moving mold cavity.
- One of these arrays of hydro-magnetic devices is shown flexibly mounted.
- FIG. 9 is a view similar to FIG. 8 but illustrates another preferred embodiment of the invention wherein the arrays of hydro-magnetic devices which are shown positioned downstream in FIG. 8 are replaced with backup rollers shown positioned downstream in FIG. 9.
- FIG. 10 is a view similar to FIG. 8, but illustrates another preferred embodiment wherein two arrays of hydro-magnetic devices which are shown positioned downstream in the upper carriage in FIG. 8 are replaced with backup rollers shown positioned downstream in FIG. 10.
- the two arrays shown positioned downstream in the lower carriage in FIG. 10 in opposition to the backup rollers are non-magnetic coolant pillows.
- FIG. 11 is an enlarged cross-sectional elevation view as seen looking downstream from the upstream vantage point of FIG. 5 showing a permanent magnetic device rotatable by a fluid-driven magnet-rotating mechanism.
- the permanent magnetic device is shown in the open-circuit or "off" position.
- FIG. 12 is a cross-sectional elevation view of the apparatus of FIG. 11 as seen from the outboard vantage point of FIG. 4.
- FIG. 12 is a section taken along XII-XII in FIG. 11.
- FIG. 13 shows the use of a movable magnetically soft ferromagnetic shunt in an alternative embodiment of the invention instead of using the rotatable permanent magnetic devices shown in FIGS. 11 and 12.
- FIG. 13 is an oblique view, as seen generally from the vantage point of FIG. 5, illustratively showing an array of hydro-magnetic devices positioned below a moving casting belt with a castellated bar of magnetically soft ferromagnetic material acting as a shunt and being shown in the "off" position (pole faces demagnetized) .
- FIG. 14 is a view similar to FIG. 13 but shows the shunt bar in the "on" position (pole faces magnetized) .
- FIG. 15 shows hysteresis loops of two different permanent magnetic materials: alnico 5 and a most preferred permanent magnetic material described in detail later and which we employ in permanent magnets used in the most preferred embodiments of the invention as described.
- FIG. 16 is an elevational longitudinal sectional view as seen from the outboard side of the machine showing an alternate hydro-magnetic device or sub-assembly in a hydro-magnetic pillow array. This hydro-magnetic device is shown surrounded by other elements of the upper carriage of a belt-type casting machine such as shown in FIG. 1.
- FIG. 16 is analogous to FIG. 4A which shows the lower casting belt and lower nip pulley; whereas FIG. 16 shows the upper casting belt and upper nip pulley in cooperative association with the present alternative construction of an embodiment of the invention.
- FIG. 17 is an enlarged partial sectional view showing a plurality of magnetic circuits according to the present alternative construction, with thin, fast-travelling coolant films passing through gaps between pole faces and the reverse surface of a moving casting belt.
- the left portion of this view is as indicated by A-A in FIGS. 16 and 19.
- the right portion of FIG. 17 is taken along A'-A'.
- the relative thickness of the coolant- film gap is here exaggerated for clarity of illustration.
- FIG. 18 is an enlarged partial sectional view similar to FIG. 17, but FIG. 18 is a view farther downstream, away from the nip pulley fins, with left and right portions of FIG. 18 being located along B-B and B'-B' respectively, in FIGS. 16 and 19.
- FIG. 19 is an enlarged portion of FIG. 16, showing particularly the pattern of assembly of the rotatable magnets.
- twin-belt casting machines typically have upper and lower carriages for revolving upper and lower casting belts.
- the description will relate to the lower carriage.
- the pass line followed by the freezing metal is generally straight.
- the pass line may follow a slightly curved path.
- the pass line may extend generally straight in a direction longitudinally of the machine while the belt may be slightly bowed in a direction transversely of the machine in a portion of the mold cavity.
- the pass line or its guides provided by the positions of the pole faces in an array may be referred to as a "coplanar array" or "even surface array”.
- an "even" belt may be moving along a pass line which follows a slightly curved path, the even belt may be considered to be in a flat condition when it is moving along the pass line with a desired evenness throughout the extent of the pass line, and also an even belt which is slightly bowed transversely at some portion of the pass line may be considered to be in a flat condition when it is moving along the pass line with a desired evenness throughout the extent of the pass line.
- An array of magnetic pole faces for guiding a moving casting belt along a pass line with a desired evenness may be called a "coplanar array" of magnetic pole faces or may be called an "even surface array".
- FIG. 1 is a view of a relatively wide twin-belt casting machine 36 as seen from upstream, above, and from the outboard side.
- the lower carriage is indicated at L and the upper carriage at U.
- molten-metal-feeding equipment (not shown) which is known in the art of continuous casting machines, molten metal is introduced into the entrance end 49 of the moving mold cavity or mold space C (FIGS. 4, 4A, 5, 6, 8, 9 and 10). This introduction of molten metal is schematically indicated by the large open arrow 37 shown at the left in FIG. 1.
- a continuously cast product P shown at the right in FIG. 1 emerges (arrow 57) from the exit end of moving mold cavity C.
- the lower and upper sides of the moving mold cavity C are bounded by revolving lower and upper endless, flexible, thin-gauge, heat-conducting casting belts 50 and 52, respectively.
- These casting belts 50, 52 in preferred embodiments of this invention are fabricated from magnetically soft ferromagnetic material. For example, they are formed of metallic material such as quarter-hard-rolled low-carbon sheet steel.
- the front surfaces of the casting belts may be suitably treated as known in the art, for example by sand blasting and/or by coating them.
- the two lateral sides of the moving mold cavity C are bounded by two revolving block-chain edge dams 54 as known in the art.
- Lower belt 50 and block chains 54 revolve as shown by motion arrows 55 around a lower (nip) pulley 56 opposite the entrance (upstream) end 49 of the moving mold cavity and around a lower pulley 58 opposite the exit end of the moving mold cavity.
- Upper belt 52 revolves around an upper upstream (nip) pulley 60 and around an upper downstream pulley 62.
- the structure and operation of such twin-belt casting machines is well known in the art of belt-type casting machines. Further information if desired by the reader regarding such machines may be found in the herein referenced patents of Hazelett et al.
- the viewpoint of FIG. 2 is indicated in FIGS. 3 and 8 by the dashed and dotted line II-II.
- the lower casting belt 50 is shown being guided by an array generally indicated at 51 of hydro-magnetic devices 38.
- the array 51 may be called a hydro-magnetic pillow.
- Each hydro-magnetic device includes a magnetic pole member 39 extending longitudinally with respect to the upstream-downstrea direction (arrow 61) of the moving mold cavity C.
- these elongated pole members 39 are arranged in spaced parallel relationship. Their top surfaces are shown providing a coplanar array of magnetic pole faces 34. Between these elongated pole members 39 are defined elongated spaces 66 which are shown extending longitudinally with respect to the mold cavity.
- the elongated pole members 39 are formed of magnetically soft ferromagnetic material, for example such as magnetically soft steel such as type 430 chromium stainless steel.
- the casting belt 50 moves in close proximity to the magnetic pole faces 34 being supported by hydrodynamic forces provided by pumped liquid coolant issuing from throttling nozzles as will be explained later.
- an array 51 of hydro-magnetic devices 38 we mount a multiplicity of relatively compact permanent magnets 32 having North and South magnetic polarities as indicated on each magnet in FIG. 2 at N 1 and S', respectively. These magnets are interposed into the elongated spaces 66 between successive spaced parallel elongated pole members 39 in the array 51. It is preferred that there be at least one of these permanent magnets 32 positioned in each space 66 so that in an overall array 51, as will be understood from FIGS. 3 and 5, each pole member 39 in an array (except as shown in FIG. 3 for the two outermost pole members 39-0 in the array) has a pair of same polarity permanent magnet poles facing toward its opposite sides.
- pairs of same polarity permanent magnet poles have alternate North (N') and South (S') polarity across the array 51.
- the pole member 39 at the left has a pair of North polarity permanent magnet poles N' facing toward its opposite sides.
- the next successive pole member 39 seen at the center in FIG. 2 has a pair of South polarity permanent magnet poles S • facing toward its opposite sides.
- the next successive pole member 39 seen at the right in FIG. 2 has a pair of North polarity permanent magnet poles N 1 facing toward its opposite sides, and so forth across the array 51.
- pole faces 34 of pole members 39 in successive hydro-magnetic devices 38 spaced across the array 51 have alternate North (N) and South (S) polarities providing powerful reach-out attraction force (pull) on the moving casting belt 50 (FIGS. 2, 5 and 6).
- an array 51 as seen in FIG. 3 there are a plurality of permanent magnets 32, for example five are shown in FIG. 4, interposed in each of the elongated spaces 66 at longitudinally-spaced, longitudinally-aligned positions along the length of the elongated pole members 39, as is seen most clearly in FIG. 3.
- a first of the magnets 32 in each space 66 is positioned near an upstream end 118 of the pole faces 34 of two neighboring pole members 39.
- a last of the plurality of magnets in each space is positioned near a downstream end 120 of the pole faces 34 of the two neighboring pole members 39.
- FIG 4A which shows a nose array 51n the five magnets in each space 66 are shown positioned adjacent to each other near a downstream end of this nose array in order to avoid interference with pulley fins 128.
- the dashed lines 30 indicate a complete magnetic circuit shown near the center of FIG. 6 and indicate portions of two other magnetic circuits at the left and right.
- the relative thickness of casting belt 50 and the size of gaps (spacings) 75 between pole faces 34 and the belt are exaggerated for clarity of illustration.
- a complete magnetic circuit 30 can be traced starting from the North pole N' of a permanent magnet 32 seen in the center of FIG. 6. For example, with five magnets in each space 66, this circuit 30 is representative of each of five such circuits in regard to each space 66 and two neighboring pole members 39.
- the magnetic circuit extends from magnet pole N' into a first pole member 39 of a hydro-magnetic device 38 and thence extends within this first member to a first pole face 34 thereon where the powerful magnetomotive force of the magnet magnetizes a powerful first magnetic pole N at this first pole face.
- the circuit extends from this first pole face 34 across a first gap 75 and enters the magnetically soft ferromagnetic belt 50 and then extends within the belt toward a second gap 75.
- the circuit extends across this second gap 75 and enters a pole face 34 on a neighboring pole member of a neighboring hydro-magnetic device 38 in the array 51, entering at a powerful South magnetic pole S magnetized by the powerful magnetomotive force of the magnet 32.
- the circuit extends within the second pole member 39 to the magnet pole S* and enters this pole S. This magnetic circuit is completed within the magnet from its pole S' to its pole N'.
- pole members 39 in an array 51 are shown spaced uniformly on centers. This center-to-center spacing of pole members 39 may, for example, be in a range from about 3/4 inch to about 2 inches. These elongated pole members may be, for example, about 1/2 inch thick defining elongated spaces 66 between neighboring pole members extending longitudinally relative to the mold cavity. In FIG. 6, these spaces are shown slightly wider near belt 50 due to slight narrowing of pole members 39 toward their pole faces 34. Permanent magnets 32 in the embodiments as shown extend from pole S' to pole N' .
- Each permanent magnet 32 may comprise a plurality of individual permanent magnet bodies arranged end-to-end in series in appropriate additive North-to-South polarity and/or a plurality of individual permanent magnet bodies arranged side-by-side in parallel in appropriate additive side-by-side relationship for providing a very powerful magnet 32 having resultant North (N 1 ) and South (S') polarities at its opposite ends or faces 33 (FIGS. 3A and 6) through which magnetic flux travels. If the magnet bodies are formed of material subject to corrosion, then these bodies are suitably coated for resisting corrosion, for example being nickel plated.
- These permanent magnets 32 as shown in FIGS. 2, 3, 5 and 6 are arranged as rectangular parallelepipeds being about one-half inch long to about one-inch long in the S' to N 1 direction of their internal magnetic flux and at least about one square inch in transverse cross section.
- end surfaces 33 of magnets 32 having poles N' and S* be placed in actual contact with side surfaces of the pole members 39. These magnet end surfaces 33 need only be adjacent to the side surfaces of their neighboring pole members.
- the term "adjacent" as used herein is intended to include actual contact. If there is any spacing between end surfaces 33 and side surfaces of pole members 39, then the resulting air gaps between end surfaces 33 and pole members 39 should be sufficiently small in the direction of the magnetic flux circuit 30 so that in practical effect there are only two significant gaps 75 in each complete magnetic circuit 30.
- These attraction forces diminish relatively slowly with increasing gap spacings 75, as will be explained further in connection with FIGS. 7 and 7A.
- This liquid coolant 93 is pumped into a tunnel passageway 92 extending longitudinally in each pole member 39 by means of a coolant supply system shown in FIGS. 4 and 4A.
- the liquid coolant 93 which is typically water containing rust inhibitors is suitably filtered to remove particulate matter and then is pumped into a header pipe 100 extending transversely within the lower carriage L. An end of this header pipe 100 is shown in FIG. 1.
- pumped coolant 93 may be pressurized, for example, above about 30 pounds per square inch (p.s.i.), but not pressurized too greatly in a particular machine set-up so as to levitate the belt beyond gap spacings 75 wherein available reach-out magnetic attraction can forcibly stabilize the belt against thermal distortions.
- Supply tubes 98 extend from header 100. Each such supply tube connects to a diagonal drilled passage 96 in a pole member 39 connecting with a tunnel passage 92 in the pole member.
- an elongated pole member 39 as shown in FIG. 4A is modified as compared with the shape as shown in FIG. 4 in order that an elongated pole member having the FIG. 4A configuration can project upstream beyond the nip region 110 so its nose portion 39n can fit into grooves 127 (FIG. 4A) between fins 128 on the lower nip pulley roll 56.
- This nip region 110 of the entrance 49 is shown in FIG. 4A by a dash and dot line passing through the entrance and through the axis 111 of the lower nip pulley 56 and also passing through the axis (not shown) of the upper nip pulley 60 (FIG. 1) .
- a tunnel passage 92 extending longitudinally in an elongated pole member 39 may be considered to be a plenum tunnel, because it supplies pumped coolant 93 to numerous ones of the specially devised throttling nozzles which include fixedly throttling passageways 90 and pressure pockets 102 facing the belt and rimmed by pole faces 34.
- the upstream and downstream end of each tunnel passage 92 is plugged as shown at 94 in FIGS. 4 and 4A.
- pumped coolant 93 From the tunnel passageway 92 pumped coolant 93 enters fixedly throttling passageways 90 leading throttled pumped coolant flow 97 into pressure pockets 102 facing toward the reverse surface of the casting belt.
- FIGS. 2, 3, 3A, 4 and 5 are a multiplicity of these pressure pockets. They are shown as being oval shape, elongated longitudinally of the pole surfaces 34.
- these pressure pockets 102 may be about 3/16ths of an inch deep and about 3/16 of an inch wide with a length longitudinally of pole surfaces 34 of about 3/8 of an inch.
- These oval-shaped pressure pockets 102 are shown closely spaced along the length of the pole faces 34, for example with a spacing of about one-eighth of an inch between respective downstream and upstream ends of their oval shapes; so that as shown, for example there are two pressure pockets per inch longitudinally of the pole surfaces 34 (i.e., a center-to-center spacing of about one-half inch) .
- each pressure pocket 102 has an area of about 0.06 of a square inch facing the belt surface.
- Throttled pumped coolant flow 97 in the pressure pockets 102 applies pushing force (repulsive force) against the reverse surface of the moving belt 50.
- This throttled pumped coolant flow 97 escapes from each pressure pocket in the form of fast-travelling liquid films 114 radiating outwardly from the pressure pocket into the gaps 75 and travelling across the pole face 34 which rims the pressure pocket.
- each of the fast-travelling liquid films 114 also applies dynamic pushing force (repulsive force) against the reverse surface of the belt.
- each throttling passageway 90 is to isolate (decouple, uncouple) its associated pressure pocket 102 from the associated tunnel passage 92 from which pumped liquid coolant 93 is being fed into the pressure pocket.
- any variation of pressure of coolant flow 97 into a particular pocket 102 does not affect the pressure of the pumped coolant 93 in the nearby tunnel passage 92.
- no positive feedback effect takes place with respect to localized pressure variations which may momentarily occur in coolant flow 97 into any pressure pocket. Consequently, each pressure pocket 102 with its coolant flow 97 and its radiating flowing films 114 functions independently of neighboring pockets. Behavior of any flow 97 and any film 114 does not significantly affect the pressure of pumped coolant 93 in tunnel passages 92 and does not significantly affect the functioning of any other pressure pockets nor any other coolant films.
- the throttling passageways 90 (which may be considered to be fixed throttling orifices of significant length) are preferred to be no larger in inside diameter (I.D.) for example than about l/16th of an inch (about 0.063") and preferably are not smaller than about 0.04 of an inch, due to possibility of an inadvertent clogging of openings having a smaller I.D. than about 0.04". As shown in FIG. 6, the passageways 90 are about three-quarters of an inch long with an I.D. of about 0.045 of an inch.
- the pressure of pumped liquid 93 in the header 100 may be in a range above about 30 p.s.i. but not pressurized too greatly as stated above.
- header pressure is assumed to be in a range of about 100 p.s.i. to about 110 p.s.i. (in a range of about 7 bars). Since a relatively insignificant pressure drop is assumed to occur in a supply tube 98 and in the connection passage 96, the pressure of the coolant 93 (FIG. 6) in each tunnel passage 92 is in a range of about 100 p.s.i. to about 110 p.s.i.
- the moving casting belt 50 in FIG. 6 is stable in position in response to balancing of the pull/push forces.
- the moving belt is being supported by throttled pressurized flow 97 and also by relatively thin films 114 of fast-travelling coolant escaping from pressure pocket 102 through gaps 75.
- Flow as used herein means amount of coolant volume (i.e., quantity) per unit of time. Consequently, for example, under these initial conditions a pressure drop of about 30 to about 40 p.s.i. is assumed to occur in throttling passageway 90.
- the pressure of flow 97 entering into the pressure pocket 102 is the header pressure of about 100 to about 110 p.s.i. minus a pressure drop of about 30 to about 40 p.s.i. causing pressure of flow 97 to be assumed to be in a range of about 60 to about 80 p.s.i. in these initial conditions of a stable position of the moving belt.
- thermal distortion starts to cause a localized region of the moving belt 50 in FIG. 6 to become displaced farther from the magnetic pole faces 34, thereby enlarging the gaps 75, resulting in increased thickness of fast-travelling films 114, resulting immediately in increased escaping flow in these films 114 radiating from the pressure pocket 102, resulting in increased flow 97 into the pressure pocket, resulting in an immediate increase in pressure drop occurring in throttling passageway 90 which pressure drop becomes, for example, about 40 to about 50 p.s.i.
- throttled pressurized coolant flows 97 and the fast-travelling coolant films 114 are emitted from pressure pockets 102 immediately contiguous with pole faces 34 at which magnetic flux is powerfully active in circuits 30.
- the reach-out magnetic attraction pull forces and hydrodynamic push forces are balanced in pull/push relationship in their own immediate locale, i.e., there is a balance of opposed pull and push forces occurring over only a small lateral distance along the thin-gauge casting belt 50. Consequently, only an insignificant moment arm is involved in regard to effective application to the belt of these opposed pull and push forces.
- FIG. 3A In FIG. 3A are shown directions and patterns of fast-travelling coolant films escaping past magnetic pole faces 34 as indicated by flow lines 114.
- these fast-travelling films 114 effectively scour heat away from the reverse surface of the casting belt (not shown in FIG. 3A) cutting past or through any slower moving coolant for effectively cooling the belt.
- unidirectional sweeping flow 115 which is described later
- fast-travelling coolant films 114 after escaping past respective pole faces 34 would collide with fast-travelling coolant films simultaneously escaping past pole faces 34 in a neighboring pole member, and an intermediate turbulent collision zone 113 may occur near a mid-line of each elongated space 66 wherein coolant would have substantially zero net unidirectional momentum, thereby being ineffective for clearing coolant away from pole members 39, except for gravitational fall-off or spill-off effects.
- a fast-moving, high-volume, unidirectional sweeping coolant flow 115 (FIGS. 3A, 4 and 4A) is shown being introduced into an upstream end of each space 66.
- This unidirectional sweeping flow 115 prevents any flows of coolant near the reverse surface of the belt from becoming relatively too slow for suitably scouring heat away from this reverse surface (i.e., too slow for suitably cooling the belt so as to prevent thermal damage to the casting belt) .
- This sweeping flow 115 causes all coolant to end up flowing in one direction while maintaining a substantial relative velocity between coolant and belt at all points on the reverse surface of the casting belt for preventing thermal damage to the belt.
- These unidirectional sweeping flows 115 of coolant are provided as shown most clearly in FIGS. 4 and 4A by sweep nozzles 112 which communicate with upstream ends of the tunnel passages 92 near the upstream plugs 94 so that pumped coolant flow 93 enters these sweep nozzles.
- Each sweep nozzle 112 (FIGS. 4 and 4A) is shown aimed downstream at an acute angle at a relatively shallow angle of approach toward the reverse surface of the moving casting belt.
- Each sweep nozzle 112 has a hood-like fingernail deflector 116 mounted near a downstream discharge end of the sweep nozzle for laterally spreading a forceful stream 115 of sweeping coolant issuing at high velocity from the sweep nozzle.
- the fingernail deflectors 116 are shown aimed toward the reverse surface of the moving casting belt 50 at a slightly more acute angle (i.e., a smaller angle) than their associated sweep nozzles 112.
- Each fingernail deflector 116 directs the forceful stream 115 (FIG. 3A) issuing from its sweep nozzle against the belt's reverse surface at an acute angle of impingement in a relatively uniform, closely-defined location on the casting belt near an upstream, prow-shaped, pointed end 118 (most clearly seen in FIGS. 3 and 3A) of each elongated pole member 39.
- Downstream ends of the pole members 39 also are normally pointed in a prow-shape 120 (FIGS. 2 and 3) like their upstream prows 118.
- the bore of sweep nozzle 112 has a cross-sectional area which is larger than throttling orifices 90 but smaller than the tunnel passage 92.
- the relative proportion of cross-sectional area of sweep nozzle bore 112 compared with cross-sectional area of the tunnel passage 92 is determined and scaled in size such that at the pumped pressure of coolant 93 in the headers 100 (FIGS. 4 and 4A) there is no starving of the coolant flows 97 (FIG. 6) into the pressure pockets 102 and also no starving of the sweeping flows 115.
- velocity, flow and momentum of sweeping coolant 115 are fast enough and voluminous enough to merge with and deflect and sweepingly to carry away in the downstream direction 61 all of turbulent coolant 113 and all fast-travelling films 114 after they escape from the gaps 75, while maintaining a substantial relative velocity at all points on the reverse surface of the belt sufficient to prevent thermal damage to the belt.
- a deflector scoop 122 which extends transversely relative to the moving belt, scoops coolant away from the moving belt.
- An associated coolant-removal gutter serves to return this scooped-away coolant to a supply reservoir (not shown) .
- Such a coolant deflector scoop 122 and its coolant removal gutter may be similar to deflector scoops shown in FIGS. 6 and 7 of U.S. Patent No. 3,036,348 of Hazelett et al. listed on the cover page, except that deflector scoops 122 do not include header ducts nor nozzles for re-application of coolant to the belt.
- magnetic pole members 39 (only one is shown) have a slender upstream-projecting nose end portion 39n which projects beyond the nip region 110 so that this nose portion 39n fits into a groove 127 between two fins 128 on a nip pulley roll.
- sweep nozzle 112 and its deflector fingernail 116 both are positioned slightly upstream relative to nip region 110.
- An array of hydro-magnetic devices 38 having slender nose end portions 39n are called nose arrays as indicated at 51n in FIGS. 8, 9 and 10.
- nip pulleys 56, 60 and their fins 128 which are illustratively shown as being integral with the pulley body are made of non-magnetic material, i.e., diamagnetic or paramagnetic material, for example austenitic stainless steel, Type 304, so the fins and nip pulleys do not invite leakage flux to leave pole members 39, 39n and enter the fins and pulleys, which would reduce reach-out flux available from pole faces 34 of the nose portions 39n of the pole members 39 for stabilizing the moving casting belts.
- non-magnetic material i.e., diamagnetic or paramagnetic material, for example austenitic stainless steel, Type 304
- the fins may be made of such non-magnetic stainless steel, while the body of the pulley is made of magnetically soft ferromagnetic material for completing magnetic circuits in cooperation with pole member nose portions 39n.
- the fins 128 may be made of magnetically soft ferromagnetic material, while the body of the pulley is made of non-magnetic material. Then, reach-out permanent magnets are arranged to magnetize the fins with alternate North and South polarity during operation of the machine for attracting and stabilizing the belt. These magnets may be movably mounted with operating mechanism, for example such as shown in FIGS.
- FIGS. 13 and 14 may be used for diminishing the magnetic attraction between the fins and the belt for facilitating such removal and installation.
- the permanent magnetic material in each of the permanent magnets 32 which powerfully magnetize the magnetic circuits 30 (FIG. 6) and also powerfully magnetize the whole magnetic pole members 39 for providing the powerful reach-out attraction forces (pull) on a moving casting belt 50 containing magnetically soft ferromagnetic material has certain very important critical characteristics: (1) A sample of this permanent magnetic material has a normal hysteresis loop (B-H loop) which crosses the B-axis at a point wherein the sample has a residual induction B r with a magnetic flux density equal to or greater than about 8,000 Gauss.
- B-H loop normal hysteresis loop
- a sample of this permanent magnetic material has a normal hysteresis loop (B-H loop) wherein a straight line tangent to a midpoint of the portion of the loop in the second or fourth quadrant has a slope indicating a midpoint differential demagnetizing permeability in ⁇ Gauss per ⁇ Oersted equal to or less than about 4 with the magnetic permeability of air being taken as 1.
- this permanent magnetic material needs to have a great degree of permanence — i.e., roughly speaking it needs to be hard to demagnetize, i.e., it is "hard” in a magnetic sense, i.e., a very large demagnetizing coercive force is required in order to demagnetize this permanent magnetic material.
- midpoint differential demagnetizing permeability of a sample of a permanent magnetic material means the slope expressed in ⁇ Gauss per ⁇ Oersted of a straight line which is tangent to the sample's B-H loop at a midpoint of the portion of this loop which is in the second or fourth quadrant.
- the sample's B/H loop is drawn on a plot wherein values of B and H are scaled along the respective vertical and horizontal axes such that B/H or ⁇ B/ ⁇ H of vacuum, i.e., the slope for the flux density B resulting from applying a coercive force H to vacuum when on this same plot is always 1; in other words, the ratio of the change in flux density ⁇ B to a change ⁇ H in applied coercive force for vacuum when drawn on this same plot is always 1.
- B/H or ⁇ B/ ⁇ H of vacuum i.e., the slope for the flux density B resulting from applying a coercive force H to vacuum when on this same plot is always 1; in other words, the ratio of the change in flux density ⁇ B to a change ⁇ H in applied coercive force for vacuum when drawn on this same plot is always 1.
- a sample of permanent magnetic material in magnets 32 has a B-H loop which crosses the B-axis at a point where the residual induction B r has a magnetic flux density in Gauss:
- a sample of permanent magnetic material in magnets 32 has a midpoint differential demagnetizing permeability expressed in ⁇ Gauss per ⁇ Oersted
- alnico 5 magnets lose control over a thermally distorting casting belt 50 or 52; whereas the present magnets 32 do not lose control in arrays 51 or 51n configured and operated as described for these preferred embodiments.
- a gap 75 of 1.5 mm at pole face 34 amounts only to 7.1%.
- an alnico 5 magnet of 1 physical inch in length divided by its assumed midpoint differential demagnetizing permeability of 30 has an "internal apparent air gap" of only 0.033 of an inch (0.84 mm).
- a gap 75 of 1.5 mm amounts to 178%. Once again it is seen that 178% is twenty-five times more devastating to magnetic attraction than 7.1%.
- the midpoint differential demagnetizing permeability of about 30 for alnico 5 was measured in Permanent Magnet Design and Application Handbook written by Professional Engineer Lester R.
- the elongated magnetic pole members 39 are shown in FIGS. 4 and 4A secured to and supported by a transverse beam 104 formed of non-magnetic material (paramagnetic or diamagnetic material) for example such as non-magnetic austenitic stainless steel. Type 303.
- the pole members 39 are seated in grooves 106 in the beam 104.
- At upstream ends of pole members 39 are fixture holes 95 for alignment and supplemental support of the pole members.
- a transverse beam 108 positioned below beam 104 is included in a chassis frame 141 of lower carriage L. This beam 108 is made of suitable structural material, for example such as structural steel.
- the arrays 51 and 5In in FIGS. 4, 4A and 5 are shown rigidly mounted to the chassis of a belt carriage by transverse beams 104, 108.
- transverse beams 104, 108 For continuous casting of some metals it may be desirable to employ hydro-magnetic arrays or pillows 51n and 51 which are rigidly mounted along the entire length of the mold cavity C.
- one or more downstream arrays 51 may be mounted on coil springs or transverse supports which may be designed to be compliant and springy. Their positions and alignment toward or away from a casting cavity C may be adjusted during operation by mechanisms not shown.
- Such belt-support backup adjustment mechanisms for adjusting compliant, springy support members may be similar to those shown and described in U.S. Patents 4,552,201; 4,671,341; 4,658,883; and 4,674,558 of Hazelett and Wood.
- a method by which springiness or compliance of the hydro-magnetic belt-stabilizing pillows arrays 51 may be adjusted is to employ different diameters of throttling passageways 90 (seen most clearly in FIG. 6) .
- the given pumping pressure may be selected within a range above about 30 psi, as may be desired for a particular belt-type casting machine using a particular moving, endless, flexible, thin-gauge, heat-conducting casting belt or belts for casting a particular metal or metal alloy.
- belt-stabilization arrays 51 of the hydro-magnetic devices 38 there are four belt-stabilization arrays 51 of the hydro-magnetic devices 38. Also there are two belt-stabilization nose arrays 51n which are operatively associated with the lower and upper nip pulley rolls 56 and 60. In these nose arrays 51n the upstream slender elongated nose portions 39n (FIG. 4A) of pole members 39 are fitted into grooves 127 between circumferential fins 128 on the respective lower and upper nip pulley rolls 56 and 60.
- coolant deflector scoops 122 positioned downstream (in the direction shown by direction arrow 61) of the nose arrays 5In and also there are such deflector scoops positioned downstream of lower and upper arrays 51 shown near an intermediate portion of the mold cavity C. Coolant exiting from downstream ends of the lower and upper downstream arrays 51 may be allowed to fall off from the reverse surface of the lower belt and to spill off from the edges of the upper belt.
- an upper downstream hydro pillow array 53 is shown flexibly mounted to the chassis frame 142 of the upper belt carriage by means of resilient mounts 140, for example such as coil springs. Magnets normally are omitted from a hydro pillow array 53.
- any deflector (and applicator) scoop 123 which precedes a finned belt-backup roller 126 is equipped with a header 101 extending transversely of the chassis frame.
- This header 101 is supplied with a flow 93 of pumped coolant and includes numerous coolant discharge nozzles 103 (only one is seen in FIG. 4A) aiming jets 105 of coolant toward a downstream-directed coolant applicator surface 107 on this deflector and coolant applicator scoop 123.
- Such a deflector and applicator scoop 123 with a header 101, discharge nozzles 103 and an applicator surface 107 is known in the art.
- a finned belt-backup roller 126 such as is known in the art.
- the upper carriage of a twin-belt caster 36 is equipped similar to the upper carriage of the twin-belt caster 36 shown in FIG. 9, namely, there are two sequences of finned belt-backup rollers each preceded by a deflector and applicator scoop 123.
- the lower carriage has two non-magnetic arrays 53 of hydrodynamic devices which are like the arrays 51 of hydro-magnetic devices 38 shown in FIGS. 2, 3, 3A, 4, 4A, 5 and 6, except that the permanent magnets 32 are omitted from the non-magnetic arrays 53.
- These arrays 53 are preceded by deflector scoops 122 configured like the deflector scoop 122 shown in FIG. 4.
- an integral, flat, liquid-coolant nozzle or "afterburner” nozzle 130 (FIGS. 4B, 4C) pointing downstream from the downstream end of each magnetic pole member 39 and being an integral part thereof.
- This aft nozzle 130 covers the area of the casting belt 50 or 52 which lies between the last pressure pocket 102 ' and the coolant-belt-strike region of the coolant 132 coming from the applicator scoop 123 after it leaves the deflector 107.
- This strike region 134 (see also FIG. 4A) of the coolant 132 as shown is approximately where a first backup-roller fin 126 is shown touching the belt 50.
- the afterburner nozzle 130 is shown in FIG.
- FIG. 4B which is an enlarged part of FIG. 4A, and in FIG. 4C which is an enlarged part of FIG. 2 in which the lower casting belt 50 is removed for clarity of illustration.
- Aft nozzle 130 replaces the area of the downstream sharp prow 120 (FIGS. 2 and 3) .
- the last (most downstream) pressure pocket, the one farthest to the right in FIG. 4B, is designated 102 • because it is different from the other pressure pockets 102, since nozzle 130 is connected into nozzle 102' and is fed liquid coolant by it.
- the throttling passage 90' feeding into pressure pocket 102' differs from other throttling feeders 90 in being of substantially larger diameter, for example being about 3/16 of an inch in diameter.
- each aft nozzle 130 is defined by the reverse surface of casting belt 50 or 52.
- the other flat side is defined by a converging platform-like ledge surface 133 formed on the aft end of pole member 39.
- the nozzle 130 is shown in FIG. 4B in longitudinal cross section and in FIG. 4C in an oblique view from above.
- the diverging downstream sweeping flow of coolant issuing from nozzle 130 is indicated by arrows 135 (FIGS. 4B and 4C) .
- any of several devices to eject liquid coolant downstream may be employed, for example, internal passages may be provided in pole members, such passages emptying at the sides of the pole members and pointing generally downstream.
- tubes or orifices and/or deflectors can be placed between the pole members in spaces 66 for dispatching liquid coolant downstream.
- a magnet-rotating device 145 may be provided as shown in FIG. 11 to reduce the powerful reach-out attraction pull of the magnetic circuits 30 on a casting belt 50 for permitting installing or removing thin-gauge, flexible casting belts without damaging them.
- This device 145 has an elongated circular cylindrical rotor 147 mounted on bearings 148 (FIG. 12) and is shown extending longitudinally of a belt carriage, being oriented parallel with pole members 39 and positioned midway between them.
- the cylindrical rotor 147 has an axially split case 146 formed in two halves of magnetically soft ferromagnetic stainless steel, for example such as type 430 stainless steel.
- This rotor contains a plurality of magnets 32 (FIG.
- the rotor case 146 has flattened sides 155 which are parallel with diametral plane 149 for effectively forming north and south poles N' and S* on the rotor case.
- Mounted closely adjacent to the rotor 147 are intermediate bridging members 154 of magnetically soft ferromagnetic material, for example such as type 430 stainless steel. These bridging members 154 have cylindrically concave surfaces 153 facing toward and closely spaced from the cylindrical rotor 147.
- 11 can be envisioned extending from a magnet north pole N 1 through an N' pole of rotor case 146, through a first bridging member 154, through a first pole member 39 to a first pole face 34, across a first gap 75 into the belt 50, extending within the belt to and then across a second gap 75 into a second pole face 34, through a second pole member 39 to a second bridging member 154 and through an S' pole of rotor case 146 to a magnet South pole S', with the magnetic circuit being completed internally within each magnet from S' to N' .
- the clevis arms 162 of all magnetic-rotating devices 145 in an array 51 may be pivotally connected to a common actuator rod which extends out of the array 51 and is operated manually or hydraulically for simultaneously turning all rotors 147 to their "on” or “off” positions.
- FIGS. 13 and 14 show an alternative mechanism for turning the magnetic circuits "on” or “off” employing a longitudinally movable shunt bar 170 of magnetically soft ferromagnetic material, for example such as type 430 stainless steel.
- This shunt bar 170 is slidable adjacent to magnetic pole members 39 from its "off” position shown in FIG. 13 to its "on” position in FIG. 14.
- This shunt bar is castellated for providing a plurality of mesa-like protrusions 172 with intervening grooves 174. These mesas are longitudinally spaced along bar 170 at center-to-center spacing equal to twice the center-to-center spacing "d" of the magnetic pole members 39.
- each mesa 172 and their intervening grooves 174 each extend about the same distance “d” along the shunt bar.
- each mesa 172 is directly adjacent to, i.e., is directly engaged with, two pole members 39 of opposite polarity, thereby bridging directly from a center of an N pole member 39 to a center of a neighboring S pole member for shunting magnetic flux being diverted away from pole faces 34.
- the elongated pole members 39 are mounted in an upstrea - downstream orientation 61, because this longitudinal upstream-downstream orientation is convenient for twin-belt casters.
- the elongated pole members 39 may be longitudinally contoured with their pole faces 34 being longitudinally curved to fit special continuous casting circumstances for instance in a one-belt continuous casting machine wherein the path of the single casting belt normally follows a gently curving arc of relatively long radius.
- the pole faces 34 in such a machine having a longitudinally curved casting cavity would curve longitudinally in a gently curving arc corresponding to the gentle arc of the moving casting belt for hydro-magnetically stabilizing the moving belt in its desired arcuate path.
- Such longitudinally curved pole faces are considered to be coplanar since they stabilize the moving casting belt in an even condition.
- the pole faces 34 may be straight in a longitudinal direction along the casting path, but an array of the pole faces may be gently bowed transversely of the straight path for gently bowing a casting belt transversely as it moves along the casting path.
- Such a transversely bowed array of pole faces is considered to be a coplanar array since they stabilize the moving casting belt in an even condition.
- a moving casting belt is forcibly held in an even condition within narrow limits of evenness (flatness) and within narrow limits of standoff (gap 75) distance from pole faces 34 of its hydrodynamic support arrays 51 or 51n of hydro-magnetic devices 38.
- magnets 32 made of permanent magnetic material exhibiting the very important critical characteristics described above are capable of successful performance in these disclosed embodiments of the invention.
- magnets 32 containing permanent magnetic materials commercially known as rare earth magnetic materials for example such as magnets comprising magnetic materials including at least one of the "rare earth” chemical elements (lanthanide family series of chemical elements numbered 57 to 71) , for example magnets preferably containing permanent magnetic materials comprising the rare earth chemical elements neodymium or samarium.
- magnets containing a permanent magnetic material comprising a compound of cobalt and samarium (Co 5 Sm) having a maximum energy product of about 20 MGOe (Mega-Gauss-Oersteds) may be used since its B-H hysteresis loop has a residual induction B r of about 9,000 gauss, and magnets containing Co 17 Sm 2 material having a maximum energy product in a range of about 22 to about 28 MGOe may be used for its B-H loop has a residual induction B r in a range of about 9,000 gauss to about 11,000 gauss.
- COgSm permanent magnetic material having a maximum energy product of about 20 MGOe has a midpoint differential demagnetizing permeability of about 1.08.
- Co 17 Sm 2 permanent magnetic materials having maximum energy products in a range of about 22 to about 28 MGOe have a midpoint differential demagnetizing permeability in a range of about 1.15 to about 1.0.
- our presently most preferred permanent magnets 32 contain a permanent magnetic material based on a tri-element (ternary) compound of iron, neodymium, and boron known generically as neodymium-iron-boron, Nd-Fe-B or NdFeB, which exhibits a maximum energy product in a range of about 25 to about 35 MGOe.
- Such magnets may be called "neo magnets", with about 32 to about 35 MGOe neo magnets presently being most preferred.
- NdFeB permanent magnetic material having a maximum energy product in the range of about 25 to about 35 MGOe have a B-H loop with a residual induction B r in a range of about 10,700 Gauss to about 12,300 Gauss and have a midpoint differential demagnetizing permeability of about 1.15.
- Neo magnets do have a low resistance to corrosion and so they are nickel-plated.
- ternary compounds such as iron-samarium-nitride and other as yet unknown ternary compound permanent magnetic materials and as yet unknown four-element (quaternary) permanent magnetic materials may become commercially available and may have B-H loops with a residual induction B r sufficiently high as shown in Table I and also may exhibit midpoint differential demagnetizing permeability sufficiently low to be suitable as shown in Table II for use in embodiments of this invention.
- FIG. 15 is shown an approximate generalized B-H loop 200 for NdFeB permanent magnetic material having a maximum energy product of about 35 MGOe.
- the B and H axes cross at origin 216.
- This "neo magnet” material exhibits a saturation magnetization as shown generally at 202 in a range of about 20,000 to about 25,000 Gauss.
- This B-H curve 200 is shown crossing the positive B axis at a point 204 where there is residual induction B r of about 12,000 to about 12,300 Gauss.
- the portion of loop 200 in the second quadrant ii advantageously is essentially a straight line 206 sloping down to a point 208 on the horizontal H axis having a value of about -11,000 Oersted.
- a negative sign for Oersteds left of the B axis indicates a coercive force H acting in an opposite direction from the original coercive force which produced the initial magnetic saturation at 202.
- a circle 210 indicates that performance of the portion 206 of loop 200 in the demagnetizing second quadrant ii is the region of present interest.
- this permanent magnetic "neo magnet” material has (1) a residual induction B r of about 12,000 to about 12,300 gauss and also has (2) a mean differential demagnetizing permeability of about 1.15, thereby providing powerful advantageous reach-out attraction force as described.
- FIG. 15 Also shown in FIG. 15 is an approximate generalized B-H loop 220 for alnico 5 having saturation magnetization.
- This alnico 5 loop crosses the B axis where there is a residual induction B r of about 12,800 Gauss as measured from the alnico 5 hysteresis loop in Figure 6-3 of Lester R. Moskowitz's above-identified Handbook.
- the alnico 5 curve 220 has a saturation magnetization not much higher than about 15,000 Gauss.
- the demagnetizing curve 222 for alnico 5 drops almost vertically and crosses the H axis at 226 at less than about 1,000 Oersteds.
- alnico 5 has a maximum energy product of less than about 7 MGOe.
- the steep dropoff of alnico 5's demagnetization curve 222 indicates a midpoint differential demagnetizing permeability at midpoint 224 of about 30, which renders alnico 5 unsuitable for use in magnets in embodiments of the present invention, as explained above.
- FIGS. 7 and 7A is shown a straight line 230 which generally represents a gradual decrease in reach-out attraction force (pull on the belt) of pole faces 34 attracting a moving casting belt such as the belt 50 plotted as a function of increasing gap spacing 75 using magnets 32 made of permanent magnetic material "neo magnets" having the most preferred characteristics, for example having a maximum energy product of 35 MGOe.
- Increasing gap spacing 75 causes an increasing equivalence of demagnetizing coercivity to be experienced by the permanent magnets 32, and thus the attraction force decreases along a generally straight line 230 having a characteristic similar to the straight-line portion 206 of B-H loop 200 in FIG. 15.
- Gap spacings 75 in inches and millimeters are shown along the horizontal axis and average pull forces (minus for magnetic attraction) on the belt and average push forces (plus for coolant repulsive effects) are shown along the vertical axis.
- Average pull forces and average push forces in p.s.i. on a casting belt are difficult to measure, and so these values along the vertical axis are only approximate; however, their relative values are generally proportioned appropriately, and it is their relative values which are significant.
- FIGS. 7 and 7A Also shown in FIGS. 7 and 7A is a steeply falling curve 240 plotted as a function of gap spacings 75 which generally represents the steeply decreasing repulsive hydrodynamic forces (push on the belt) of coolant flows 97 (FIG. 6) issuing from pressure pockets 102 and fast-travelling coolant films 114 radiating from such pockets and passing through gaps 75. Assuming that an appropriate coolant pumping pressure is being supplied in header 100, then increasing the diameter of throttling orifices 90 serves to increase the flow 97 (FIG.
- An equilibrium-stabilized state for the moving casting belt occurs under a condition generally indicated at 242 in FIGS. 7 and 7A where the two curves 230 and 240 cross each other.
- This curve-crossing point 242 is the situation in which no randomly-varying, thermal expansion belt-distorting forces (hereinafter considered as acting similar to "internal belt pressures" are present such as those due to thermally induced expansion forces arising in the belt under the influence of hot metal within the mold cavity C while the reverse surface of the belt is cooled.
- FIG. 7A 1 shows the situation during an instant of moderate internal belt pressure (equivalent to about 3 psi pressure) indicated by a plotted level of horizontal line 260'.
- FIG. 7A" shows the situation during an instant of higher internal belt pressure plotted by a horizontal line 260" (equivalent to about 5.5 psi pressure).
- FIGS. 7 and 7A there is a plot of coolant pressure but no plot of random internal belt pressure.
- FIG. 7A' there are two repulsive pressures: not only (i) that pressure due to coolant flows 97 and films 114 (per curve 240 in FIGS. 7 and 7A) but also (ii) that addition due to an instantaneous random internal belt pressure 260' plotted as being equivalent to about 3 psi in FIG. 7A'.
- These two curves 240 and 260' add up in FIG.
- the reach-out magnetic equilibrium crossing point 242" plotted on curve 230 represents only a small additional move to the right wherein reach-out pull is reduced slightly further by an additional very small percentage.
- the indeterminate crossing points 252" on the alnico 5 curve 250 represent a reduction of magnetically induced pull pressure to less than about half of what it was before the instantaneous random internal belt pressure 260" occurred.
- the gap 75 is substantially increased to about .10 to .12 mm.
- the equilibrium position 252" is no longer a definite crossing point but rather is a zone of indeterminacy, since the encounter of the two curves 250 and 240" is not a determinate large angle as advantageously is provided by reach-out magnet curve 230 but instead is a sharply acute angle (between almost parallel curves 250 and 240") which makes an equilibrium position relatively indeterminate.
- the curves 240" and 250 converge in almost parallel relationship for a substantial distance such that the secure forcible stabilizing capture of the belt has almost disappeared. Any random destabilizing internal belt pressure significantly higher than plotted at 260" would unconditionally overcome the magnetic force represented by alnico 5 curve 250 and would set the belt free from control by magnetic pole members 39 if alnico 5 magnets were attempted to be used.
- a most preferred reach-out attraction force (pull) represented by line 230 falls off less than about 50% at a gap spacing even so large as 1.5 mm (about 0.06 of an inch) in FIG. 7, and thus a reach-out pull as represented by the curve 230 forcibly is most unlikely to lose stabilization control.
- hydro-magnetic devices 38A in an embodiment of the present invention enables rotatable permanent magnets 32 to be placed in the grooves 127 between the fins 128 of each nip pulley 60 and 56.
- reach-out magnets 32 with their associated modified elongated pole members 39A are positioned all the way upstream to the nip region line 110.
- This upstream positioning of magnets 32 with their modified pole members 39A thereby provides a coplanar array 51 of spaced parallel magnetic pole faces 34 extending all of the way upstream to the nip region line 110.
- reach-out magnets 32 are shown positioned in interposed relationship between fins 128 of upstream nip pulley 60.
- the upstream end 118 of pole faces 34 of a modified elongated pole member 39A is shown positioned at the nip region line 110.
- This line 110 is the location of tangency of the casting belt 52 as it departs from nip pulley fins 128 and becomes planar (even) travelling downstream along the moving casting cavity C.
- each modified pole member 39A (including their magnets) are made to fit within the width of one pulley groove 127 (FIG. 17) .
- the center-to-center uniform spacing of the fins 128 in this embodiment as shown in FIGS. 16 to 19 is about one inch (about 25 millimeters)
- the fin thickness is about 1/8 of an inch (about 3.2 mm) with a groove width of about 7/8 of an inch (about 22 mm) .
- a modified pole member 39A is made sufficiently narrow to fit within a width of less than about 7/8 of an inch (less than about 22 mm) .
- these modified elongated pole members 39A are positioned at center-to-center parallel spacings of about one inch (about 25 mm) across the hydro-magnetic pillow array 51.
- the nip pulley 60 is shown having a solid central core with its fins integrally machined from this core, as is shown clearly in FIGS. 16, 17 and 19.
- This nip pulley 60 with its fins 128 is made of nonmagnetic stainless steel, for example such as Type 316 forged stainless steel, a non-magnetic material which has practically no effect on the magnetic situation.
- rotatable magnets 32 are placed between pulley fins 128.
- the magnets 32 are shown rotated to their casting-belt-magnetizing position
- pole faces 34 of elongated pole members 39A in successive hydro-magnetic devices 38A spaced transversely across hydro-magnetic pillow array 51 have alternate North (N) and South (S) polarities facing toward the revolving casting belt 52.
- the "lines” of magnetic flux 30 bridge (pass through) the air gaps 129 near pulley fins 128 and bridge (pass through) the pulley fins 128 themselves, which are non-magnetic. A modest amount of leakage flux 30' is unavoidable. However, sufficient desired reach-out flux 30 goes through the pole faces 34 and extends through casting belt 52 so that the belt is thereby reach-out strongly attracted toward this hydro-magnetic coplanar pillow array 51 of magnetic poles 34.
- Coolant 93 under pressure as previously described is supplied from headers (not shown) such as headers 100 in FIGS. 4 and 4A.
- This pumped coolant 93 feeds through supply tubes 98 and through diagonal passages 96 leading into upstream-directed intermediary tunnel passages 92A (FIGS. 16, 17 and 19) and thence into downstream-directed tunnel passages 92 (FIGS. 16-19) .
- These passages 92 may be considered as being plenum passages feeding pressurized coolant into fixedly throttling passageways 90. Issuing from passageways 90 coolant flow 97 of throttle-reduced pressure enters pressure pockets 102 whence fast-moving coolant films 114 (FIGS.
- tunnel passages 92 in FIGS. 4 and 4A have a portion which is upstream-directed and a portion which is downstream-directed, but their longer portions are upstream-directed.
- intermediary tunnel passages 92A which direct coolant flow 93 upstream to a significant distance beyond nip region line 110. Then, these intermediary passages 92A communicate with tunnel passages 92 at a location sufficiently far upstream from line 110 such that pumped coolant 93 flows downstream along the whole effective length of tunnel passages 92. Ends of passages 92A and 92 are closed by plugs 94.
- Sweep nozzles 112 located near the leading ends 118 of the pole faces 34 and trailing end sweep nozzles 120 (only one is seen in FIG. 16) ("afterburner" nozzles) located at the downstream end 120 of the hydro-magnetic pillow array 51 provide downstream sweeping coolant flows 115 and 135, respectively, aimed at acute angles toward the reverse surface of the casting belt 52 for forcefully deflecting downstream and propelling downstream the coolant film flows 114 (FIGS. 17 and 18) which have issued from the pressure pockets 102 and have passed through gaps 75 between pole faces 34 and the reverse surface of the belt.
- FIGS. 2 through 6 and FIGS. 11 through 14 have magnets 32 positioned between the elongated pole members 39, Moreover, for applying reach-out attraction onto the belts the internal North (N') -South (S') magnetic flux path of each of the fixed-position magnets in FIGS. 2 through 6 and in FIGS. 13 and 14 is oriented parallel with the plane of the casting belts and perpendicular to the side surfaces of these pole members 39.
- the magnetic-rotating device 145 in FIGS. 11 and 12 also is positioned between the pole members 39. In FIG.
- this magnet-rotating device 145 is shown turned to its "OFF" position wherein the internal North (N') -South (S') magnetic flux path of its magnets 32 and also of rotor 147 is oriented perpendicular to the plane of the casting belts and parallel with the side surfaces of the pole members 39.
- the control arm 162 of this rotatable device 145 is turned to the "ON" position 162' (FIG. 11)
- the internal North (N » ) -South (S') magnetic flux path of magnets 32 and their rotor 147 becomes oriented parallel with the plane of the casting belt and perpendicular to the pole members 39.
- FIG. 11 there are bridging members 154 of magnetically soft ferromagnetic material which have elongated cylindrically concave surfaces 153 facing toward and closely spaced from the elongated cylindrical rotor 147 of magnet-rotating device 145 for carrying magnetic flux between the "ON"-positioned rotor and the two nearby pole members 39.
- modified magnet-rotating devices 145A are positioned within their respective modified elongated pole members 39A. For emphasis it is repeated: each modified magnet-rotating device 145A (FIGS. 16-19) is positioned within each modified pole member 39A in contradistinction to magnet-rotating devices 145 (FIGS. 11 and 12) which are positioned between two successive pole members 39.
- each such pole member is made in first and second parts 39A-1 and 39A-2 each of which has an elongated cylindrically concave surface 153 (FIGS. 17 and 18) facing toward and closely spaced from the elongated cylindrical rotor 147 of the magnet-rotating device 145A.
- the first pole member part 39A-1 is proximate to the casting belt 52 or 50 and is configured to include a tunnel passage 92, throttling passageways 90, pressure pockets 102, magnetic pole faces 34, sweep nozzles 112 and 120, and includes other features as shown in FIGS. 16-19.
- the second pole member part 39A-2 is remote from the casting belt 52 or 50 and includes diagonal passage 96, intermediate passage 92A and includes other features as shown in FIGS. 16-19.
- This second part 39A-2 also includes a backbone portion 176 (FIG. 18) of the array 51.
- This backbone 176 is shown in FIG. 18 spanning transversely across and rigidly interconnecting a plurality of the second (remote) pole member parts 39A-2.
- This backbone 176 is shown including a plurality of elongated cylindrically curved surfaces 153 closely spaced with respective rotors 147 within the respective modified pole members 39A.
- the backbone 176 may be machined as may be desired so as to span transversely across and interconnect a large number of the remote pole member parts 39A-2.
- a plurality of narrower backbones 176 may be fabricated so as to be placed side-by-side for extending transversely across the full width of the belt.
- a transverse beam 180 (FIGS. 16 and 19) is secured to the backbone 176 (or is secured to a plurality of narrower backbones 176 placed side-by-side) .
- each remote pole part 39A-2 is diagonally machined at 180.
- proximate pole member parts 39A-1 For securing the proximate pole member parts 39A-1 to the backbone 176 longitudinally extending shoulders 182 are provided on both sides of their members 39A-1.
- Longitudinally-extending non-magnetic clamp bars 184 for example of non-magnetic stainless steel, fitted against shoulders 182 of two neighboring proximate pole parts 39A-1 are attached to the backbone 176 by non-magnetic machine screws 186 threaded into sockets 187 in the backbone 176.
- the width of clamp bars 184 is suitable for accurately positioning the proximate pole parts 39A-1 in spaced parallel relationship.
- machine screws 186 are sized so their ends will abut the ends of sockets 187 when the cylindrically curved surfaces 153 of proximate pole parts 39A-1 are suitably closely spaced from the rotors 147 of respective magnet-rotating devices 145A.
- a nose portion 39n-l of proximate pole part 39A-1 projects up above the cylindrically curved surface 153 of this proximate pole part.
- This nose portion 39n-l abuts up against the remote pole part 39A-2 at nose portion 39n-2 and contains a connection passage 92-1 providing communication between intermediate passage 92A and tunnel passage 92.
- this nose portion 39n-l helps to secure together the remote and proximate pole parts 39A-2 and 39A-1 by means of a machine screw 188 which is passed through a nose 39n-2 of remote pole part 39A-2 and is threaded into a socket 189 in the nose portion 39n-l.
- FIG. 16 shows a rotor having three magnet strings 177-1, 177-2 and 177-3.
- Two of the axially-aligned-magnet strings 177-2 and 177-3 comprise three magnets each.
- the rotor is shown having a third farthest upstream string 177-1 comprising four magnets. This latter string 177-1 extends upstream to the nip region line 110.
- the magnets 32 are shown (FIGS. 17 and 18) shaped with a pair of parallel flat sides having a pair of parallel keyway grooves 190, one in each side. These keyways 190 extend in a direction longitudinally of the elongated cylindrical rotor 147, i.e., they extend parallel with the rotor's axis of rotation.
- the magnets in each string 177-1, 177-2 and 177-3 are captured between a pair of parallel non-magnetic elongated side fittings 146 forming a split case for the magnets.
- the inner surfaces of these side fittings 146 conform with sides of magnets in a string.
- Each fitting has an elongated rib (key) projecting radially inwardly therefrom and engaging in the aligned keyways 190 of the magnets in the string.
- the peripheries of side fittings 146 and the peripheries of magnet poles N' and S' are shaped to form a circular cylindrical exterior surface for the rotor closely spaced from the concave cylindrical surfaces 153 of the proximate and remote pole parts 39A-1 and 39A-2.
- the ends of side fittings 146 are attached by machine screws 191 to respective halves of end fittings 192.
- the end fittings of the intermediate string 177-2 have sockets 193 concentric with the axis of the rotor 147.
- Journals 194 project axially from end fittings of the upstream and downstream strings 177-1 and 177-3 and their ends fit into sockets 193 and are secured in these sockets by pins 195.
- These journals 194 are supported by and are rotatable within bushings 195 which are captured by housings 196.
- An upstream end journal 194 on the upstream end fitting of the first string 177-1 is received in a bushing held by a housing 197 secured to the remote pole piece 39A-2 by a machine screw 198.
- a downstream end journal 194 projects axially through a bushing 196 held by a bracket 199 secured to the remote pole piece 39A-2 by a machine screw 198.
- each magnet rotating device 145A is turned 90° around the axis of its rotor 147 from its "ON" position shown in FIGS. 16-19 to an "OFF" position wherein its magnet poles N' and S' face in a direction parallel with the belt, i.e., like-polarity poles N' and N' and like polarity poles S' and S 1 become turned toward each other, thereby greatly reducing attraction between the pole faces 34 and the belt 52.
- An actuator lever arm 162 (FIG. 16) is fastened to the axially projecting downstream end journal 194 of each magnet-rotating device 145A in the array 51.
- a common operating rod 201 is attached by a pivot connection 203 to the end of each actuator lever arm 162 in the whole array.
- all strings of magnets in the whole array 51 are simultaneously turnable to their "ON” or “OFF” positions by shifting the common operating rod 201.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
- Soft Magnetic Materials (AREA)
Abstract
Description
Claims
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US67795396A | 1996-07-10 | 1996-07-10 | |
US677953 | 1996-07-10 | ||
US885092 | 1997-06-30 | ||
US08/885,092 US5967223A (en) | 1996-07-10 | 1997-06-30 | Permanent-magnetic hydrodynamic methods and apparatus for stabilizing a casting belt in a continuous metal-casting machine |
PCT/US1997/011507 WO1998001247A1 (en) | 1996-07-10 | 1997-07-01 | Permanent-magnetic hydrodynamic methods and apparatus for stabilizing continuous casting belts |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0912273A1 true EP0912273A1 (en) | 1999-05-06 |
EP0912273A4 EP0912273A4 (en) | 2000-11-22 |
EP0912273B1 EP0912273B1 (en) | 2003-04-16 |
Family
ID=27101920
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP97934873A Expired - Lifetime EP0912273B1 (en) | 1996-07-10 | 1997-07-01 | Permanent-magnetic hydrodynamic methods and apparatus for stabilizing continuous casting belts |
Country Status (9)
Country | Link |
---|---|
EP (1) | EP0912273B1 (en) |
JP (1) | JP2002515830A (en) |
CN (1) | CN1146483C (en) |
AT (1) | ATE237418T1 (en) |
BR (1) | BR9710159A (en) |
CA (1) | CA2259685C (en) |
DE (1) | DE69720997T2 (en) |
ES (1) | ES2196351T3 (en) |
WO (1) | WO1998001247A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6386267B1 (en) * | 1999-07-30 | 2002-05-14 | Hazelett Strip-Casting Corporation | Non-rotating, levitating, cylindrical air-pillow apparatus and method for supporting and guiding an endless flexible casting belt into the entrance of a continuous metal-casting machine |
US6755236B1 (en) | 2000-08-07 | 2004-06-29 | Alcan International Limited | Belt-cooling and guiding means for continuous belt casting of metal strip |
US7156147B1 (en) * | 2005-10-19 | 2007-01-02 | Hazelett Strip Casting Corporation | Apparatus for steering casting belts of continuous metal-casting machines equipped with non-rotating, levitating, semi-cylindrical belt support apparatus |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2382297A1 (en) * | 1977-03-04 | 1978-09-29 | Larex Ag | PROCESS FOR COOLING AND GUIDING A CIRCULAR MOVING CASTING TAPE IN A CONTINUOUS CASTING DEVICE WITH METAL PLATES |
CH608731A5 (en) * | 1975-03-18 | 1979-01-31 | Alcan Res & Dev | Continuous casting apparatus, in particular for aluminium plates |
JPS59220258A (en) * | 1983-05-28 | 1984-12-11 | Nippon Steel Corp | Device for cooling and supporting metallic belt |
JPH01218747A (en) * | 1988-02-29 | 1989-08-31 | Kawasaki Steel Corp | Continuous casting apparatus for cast strip |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59153551A (en) * | 1983-02-22 | 1984-09-01 | Nippon Kokan Kk <Nkk> | Horizontal continuous casting equipment of thin walled billet |
US4601326A (en) * | 1983-03-04 | 1986-07-22 | Electric Power Research Institute, Inc. | Ribbon casting apparatus with magnetic retainer and resilient spacer |
JPS63144847A (en) * | 1986-12-10 | 1988-06-17 | Kawasaki Steel Corp | Belt cooler for belt type continuous casting machine |
US4901785A (en) * | 1988-07-25 | 1990-02-20 | Hazelett Strip-Casting Corporation | Twin-belt continuous caster with containment and cooling of the exiting cast product for enabling high-speed casting of molten-center product |
-
1997
- 1997-07-01 CA CA002259685A patent/CA2259685C/en not_active Expired - Lifetime
- 1997-07-01 AT AT97934873T patent/ATE237418T1/en not_active IP Right Cessation
- 1997-07-01 WO PCT/US1997/011507 patent/WO1998001247A1/en active IP Right Grant
- 1997-07-01 EP EP97934873A patent/EP0912273B1/en not_active Expired - Lifetime
- 1997-07-01 JP JP50526498A patent/JP2002515830A/en active Pending
- 1997-07-01 DE DE69720997T patent/DE69720997T2/en not_active Expired - Lifetime
- 1997-07-01 CN CNB971977011A patent/CN1146483C/en not_active Expired - Lifetime
- 1997-07-01 BR BR9710159-1A patent/BR9710159A/en not_active IP Right Cessation
- 1997-07-01 ES ES97934873T patent/ES2196351T3/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CH608731A5 (en) * | 1975-03-18 | 1979-01-31 | Alcan Res & Dev | Continuous casting apparatus, in particular for aluminium plates |
FR2382297A1 (en) * | 1977-03-04 | 1978-09-29 | Larex Ag | PROCESS FOR COOLING AND GUIDING A CIRCULAR MOVING CASTING TAPE IN A CONTINUOUS CASTING DEVICE WITH METAL PLATES |
JPS59220258A (en) * | 1983-05-28 | 1984-12-11 | Nippon Steel Corp | Device for cooling and supporting metallic belt |
JPH01218747A (en) * | 1988-02-29 | 1989-08-31 | Kawasaki Steel Corp | Continuous casting apparatus for cast strip |
Non-Patent Citations (3)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 009, no. 094 (M-374), 24 April 1985 (1985-04-24) & JP 59 220258 A (SHIN NIPPON SEITETSU KK), 11 December 1984 (1984-12-11) * |
PATENT ABSTRACTS OF JAPAN vol. 013, no. 535 (M-899), 29 November 1989 (1989-11-29) & JP 01 218747 A (KAWASAKI STEEL CORP;OTHERS: 01), 31 August 1989 (1989-08-31) * |
See also references of WO9801247A1 * |
Also Published As
Publication number | Publication date |
---|---|
EP0912273A4 (en) | 2000-11-22 |
CN1229373A (en) | 1999-09-22 |
CA2259685A1 (en) | 1998-01-15 |
DE69720997T2 (en) | 2004-02-12 |
ATE237418T1 (en) | 2003-05-15 |
WO1998001247A1 (en) | 1998-01-15 |
ES2196351T3 (en) | 2003-12-16 |
CN1146483C (en) | 2004-04-21 |
DE69720997D1 (en) | 2003-05-22 |
JP2002515830A (en) | 2002-05-28 |
EP0912273B1 (en) | 2003-04-16 |
CA2259685C (en) | 2006-01-10 |
BR9710159A (en) | 2000-01-11 |
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