EP0290866A2 - Bobine excitatrice discret produisant un étanchement dans une machine de coulée continue pour le tube de coulée avec buse de sortie et la transition d'entrée de moule - Google Patents

Bobine excitatrice discret produisant un étanchement dans une machine de coulée continue pour le tube de coulée avec buse de sortie et la transition d'entrée de moule Download PDF

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Publication number
EP0290866A2
EP0290866A2 EP88106742A EP88106742A EP0290866A2 EP 0290866 A2 EP0290866 A2 EP 0290866A2 EP 88106742 A EP88106742 A EP 88106742A EP 88106742 A EP88106742 A EP 88106742A EP 0290866 A2 EP0290866 A2 EP 0290866A2
Authority
EP
European Patent Office
Prior art keywords
excitation coil
mold
inlet
recited
cavity
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.)
Withdrawn
Application number
EP88106742A
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German (de)
English (en)
Other versions
EP0290866A3 (fr
Inventor
Dennis Pavlik
Richard David Nathenson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CBS Corp
Original Assignee
Westinghouse Electric Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Publication of EP0290866A2 publication Critical patent/EP0290866A2/fr
Publication of EP0290866A3 publication Critical patent/EP0290866A3/fr
Withdrawn legal-status Critical Current

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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
    • B22D11/10—Supplying or treating molten metal
    • 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
    • B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
    • B22D11/045—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds for horizontal casting
    • B22D11/0455—Bidirectional horizontal casting
    • 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
    • B22D11/10—Supplying or treating molten metal
    • B22D11/11—Treating the molten metal
    • B22D11/114—Treating the molten metal by using agitating or vibrating means
    • B22D11/115—Treating the molten metal by using agitating or vibrating means by using magnetic fields

Definitions

  • the present invention relates to the continuous casting of metals, such as steel and, more particularly, is concerned with a discrete excitation coil incorporating multiple electrical conductor turns and independent hydrau­lic fluid flow paths for cooling the electrical conductor turns in order to produce a levitating and stabilizing force on the meniscus of the liquid metal sufficient to effectively seal the pouring tube outlet nozzle/mold inlet interface in a continuous casting machine.
  • a preferred horizontal continuous casting method is to utilize a tundish which feeds molten metal via a pouring tube downwardly through a top inlet of a horizontal contin­uous casting mold.
  • the pouring tube has an outlet nozzle which extends through the top inlet of the mold and into the pool of molten metal contained therein.
  • the mold includes interconnected top, bottom and opposite side walls which contain the molten metal in the pool thereof below the top inlet and also typically define plural outlet ports through which solidifying strands of the metal in billet or slab form are independently withdrawn from the mold.
  • a representative example of a horizontal continuous casting machine is disclosed in U.S. Patent 4,540,037 to Langner.
  • the horizontal continuous casting mold is oscillated in the horizontal direction in order to obtain a problem-free withdrawal of the strands and to realize a satisfactory surface quality of the casting:
  • it is advantageous to maintain the tundish and pouring tube stationary relative to the oscillating mold. It is there­fore necessary to provide sufficient space at the interface between the pouring tube outlet nozzle and an annular rim formed in the top wall which defines the mold top inlet to allow such relative movement.
  • the amount of mold oscillation required is dependent on factors such as slab dimensions and casting temperature. For instance, oscillations of plus or minus one centimeter are typical for slabs 15 cm by 76 cm in cross-section and composed of steel. This also necessi­tates that at the pouring tube outlet nozzle/mold inlet interface, a minimum mechanical clearance of at least l cm must be provided to accommodate the oscillation.
  • the discrete coil requires that an external mechanical frame support the coil and further that electrical insulation be provided between the coil and the mold. These requirements usually cause the distance between the bottom of the lowermost coil conductor and the melt meniscus to be unnecessarily large, reducing the electromagnetic pressure considerably.
  • a variant of the above approach of using a discrete coil with few turns is the use of a single-turn copper casting integral to the mold. While a significant advantage of this approach is that the current path is concentrated in an extremely robust, compact circuit close to the molten metal without the need for insulation, several major drawbacks are also present.
  • One drawback is that, again, the supply current must be numerically equal to the excitation ampere-turns (e.g., 100,000 amperes). As mentioned earlier, this is an extremely high value and would require a complicated cooling scheme to keep the main lead conductors cool over their long length.
  • Another drawback is that the current in the integral mold design would tend to concentrate at the top, outer surface rather than preferably at the bottom section near the molten metal. Still another drawback is that there exists at two points about the metal meniscus a magnetic null point either in the insulation space between inlet and outlet conductor leads or where the current divides in a one-half turn type arrangement.
  • the present invention resides in a continuous casting machine including a gener­ally horizontal continuous casting mold having an upper inlet, an internal cavity communicating with and disposed below said inlet for receiving molten metal through said inlet into said cavity, and at least one outlet communicat­ing with said cavity for withdrawing a strand of solidify­ing metal through said outlet from said cavity, and a tube disposed above said mold and having an outlet nozzle portion which extends downwardly through said mold inlet into said mold cavity, a discrete excitation coil for generating an electromagnetic levitating and stabilizing force which acts upon the meniscus of the molten metal in said mold cavity at the region of said mold inlet for counteracting the head pressure of molten metal contained within said pouring tube and thereby providing a seal in the area of an interface between said mold inlet and said outlet nozzle portion of said pouring tube, said excitation coil characterized by: (a) means defining multiple elec­trical conductor turns disposed in series and being capable of carrying an electrical current of adequate density
  • the means defining the multi­ple turns of the excitation coil is an outer electrical conductor
  • the means defining the plural fluid flow paths are plural inner fluid channels being surrounded by, and in contact with, the outer electrical conductor.
  • the outer electrical conductor is in the form of a solid conductive metal tube and the inner coolant channels are in the form of hollow passages formed in the solid tube.
  • the outer electrical conductor is formed by an annular arrangement of electrically conductive metallic strands and the inner coolant channels are in the form of low-conductive tubes surrounded by the conductive strands.
  • the main lead current is only a small fraction of the excitation ampere-turns (e.g., 2,000 amps as compared to 100,000 amps). This current level is easily supplied over the practical range of levitation frequencies for this application (100 to 1,000 Hertz).
  • the coil conductor arrangement is conductive to multiple independent cooling paths. This further increases the effective operating current density of the coil. Fourth, there are no significant local perturbations in the magnetic field about the periphery of the coil.
  • the numerous small conductors allow for the accurate placement of the excitation ampere-turns in an optimum distribution. Furthermore, there is no significant redistribution of the current within the coil during operation, as would occur in the few large turns or inte­gral coil/mold excitation in the prior art which would result in degradation of the effectiveness of the excita­tion in creating levitation forces in the material to be levitated.
  • the many-turn coil also opens the possibility for further significant reductions in the supply current magnitude and the size of the power supply through the use of "resonant tuning". Resonant turning is a well developed technique in induction heating systems whereby a capacitor is placed electrically in parallel with the induction coil (in this case the levitating coil).
  • a horizontal continuous casting machine generally designated by the numeral 10, adapted for continuous casting of various types of strands, for instances billets, of metal, such as steel.
  • the continuous casting machine 10 includes a suitable supply vessel, such as a casting ladle 12, from which issues a hot molten metal stream through a first pouring tube 14 into a further supply vessel, such as a tundish 16.
  • the tundish 16 in turn, infeeds the molten metal contained therein through a second pouring tube 18 into a generally horizon­tal continuous casting mold 20.
  • the continuous casting mold 20 has generally horizontal, spaced apart top and bottom walls 22, 24 being interconnected by generally vertical, spaced apart side walls (not shown) which define an internal cavity 26.
  • a generally circular upper inlet 28 is formed in the top wall 22 of the mold 20 which communicates with the cavity 26 being located therebelow.
  • the mold cavity 26 receives molten metal through the upper inlet 28 from the tundish 16 via an outlet nozzle portion 30 of the second pouring tube 18 which extends downwardly into the central region of the cavity.
  • the mold cavity 26 has a pair of opposite compart­ments 32 with corresponding outlets 34.
  • the mold 20 is formed of a good thermally conductive material, such as copper, which is chilled by a coolant, such as water, circulated through cooling passages 36 formed in its walls 22, 24 to initiate solidification of the molten metal as it flows in opposite directions into the cavity compartments 32.
  • a coolant such as water
  • Partially solidified metal strands 38 formed in the two mold compartments 32, respectively, are simultane­ously bi-directionally withdrawn in opposite directions through the outlets 34 by suitable withdrawal devices, such as pairs of synchronized driven pinch rolls 40.
  • suitable withdrawal devices such as pairs of synchronized driven pinch rolls 40.
  • the mold is constantly oscillated horizontally along its longitudinal axis by a mold oscillation mechanism, generally indicated at 42.
  • the mold oscillation mechanism 42 includes a mold table 44 upon which is supported rollers 46 rotatably attached to the bottom mold wall 24.
  • a suitable oscillat­ing drive unit 48 is coupled to the bottom wall 24 of the mold 20 for reciprocally oscillating the mold (20) essen­tially horizontally.
  • oscillation travel is dependent on factors such as slab dimensions and casting temperatures, oscillations typically amount to a fraction of a cm. For example, for casting a slab 15 by 76 cm and composed of steel, oscillations of plus or minus l cm are typical.
  • the mold upper inlet 28 must be of a size sufficient to not only accommodate the lower outlet nozzle portion 30 of the second pouring tube 18 but to also permit the oscillatory movement to be satisfactorily performed.
  • the radial separation or space between the mold 20 and second pouring tube 18 at the region of the interface between the pouring tube outlet nozzle portion 30 and mold upper inlet 28 must be somewhat greater than the oscillating stroke.
  • an elec­tromagnetic sealing device in the form of an improved discrete excitation coil 60 is supported coaxially about the pouring tube 18 in the space or separation between its outlet nozzle portion 30 and an internal annular rim portion 52 of the mold top wall 22 defining the upper inlet 28.
  • the coil 60 is preferably supported to the wall rim portion 52 by an annular support member 54.
  • the discrete excitation coil 50 being powered by any suitable alternating-current power source (not shown), generates an electromagnetic levitating and stabilizing force.
  • the electromagnetic force acts upon the meniscus 56 of the molten metal in the cavity 26 at the region of the upper inlet 28 so as to counteract the head pressure of the molten metal contained within the second pouring tube 18.
  • the force generated by the coil 50 provides a seal in the area of the interface between the mold upper inlet 28 and the outlet nozzle portion 30 of the second pouring tube 18 which prevents overflow of molten metal through the upper inlet 28.
  • the coil 50 basically includes means in the form of an outer electrical conductor 58 which defines multiple electrical conductor turns 60 connected in series and being capable of carrying an electrical current of adequate density to generate the electromagnetic force.
  • the coil 50 also includes plural inner fluid channels 62 which define fluid flow paths being surrounded by, and in contact with, the outer electrical conductor 58.
  • the inner fluid chan­nels 62 are less in number than the number of the multiple turns 60 of the conductor 58. In the embodiment seen in Fig. 4, there are forty turns 60 in the conductor 58, whereas there are only three fluid channels 62.
  • the inner fluid channels 62 are disposed in parallel to, but independent of, one another and in close proximity to, but preferably isolated from, the multiple turns 60 of the conductor 58. Coolant fluid circulated in the independent flow paths of the inner fluid channels 62 can thereby provide sufficient cooling of; the multiple conductor turns 60 to facilitate conduction therethrough of a high enough density electrical current to produce the required electromagnetic force.
  • the force required for use in continuous steel casting must typically be capable of providing on the order of a .06 kPa levitat­ing pressure.
  • Fig. 4 schematically illustrates the coil 50 which, as mentioned above, has forty-two turns 60 connected electrically in series and three channels 62 defining three independent hydraulic coolant flow paths.
  • electrical current flows progressively from turn #1 to #42.
  • the outer conductor 58 and successive ones of the three inner channels 62 are wound continuously from turn #1 to #14, from turn #15 to #28, and from turn #29 to #42.
  • the independent electrical current and hydraulic coolant paths separate, in the manner depicted in Fig. 5.
  • a separate hydraulic coolant path is provid­ed for each of turns #1 through #14, #15 through #28, and #29 through #42, with the electrical current path being continuous from turn #1 through #42.
  • Fig. 5 the separation of the coolant channel 62 in the conductor turn #14 is illustrated.
  • the channel 62 is separated into an insulated hydraulic outlet connec­tion 64 and inlet connection 66.
  • a conducting joint 68 is provided to ensure that the electrical path is continuous in the outer conductor 58 even though the coolant flow path is discontinuous.
  • the electrical current flows across the conducting joint 68 as the coolant fluid sepa­rates via the outlet and inlet connections 64, 66.
  • the configuration of the coil 50 in Figs. 3-5 can be called a vertical helical arrangement. It requires that two verti­ cal columns of conductor turns 60 make up each hydraulic flow path.
  • Figs. 6 and 7 depict two different embodiments of the conductor 58 and channel 62 composing the coil 50.
  • the outer conductor 58 of the coil 50 is in the form of a solid conductive metal tube 70
  • the inner coolant channel 62 is in the form of a hollow passage 72 formed in the solid tube 70.
  • the outer conduc­tor 58 of the coil 50 is in the form of an annular arrange­ment of electrically conductive metallic strands 74
  • the inner coolant channel 62 is in the form of a low-conductive hollow tube 76 surrounded by the annular bundle of conductive strands 74.
  • Tube 76 may also be non-conductive.
  • Fig. 8 merely depicts a variation on the vertical helix wound coil of Fig. 4.
  • Fig. 9 is a configuration called a spiral pancake single layer winding, while the configura­tion of Fig. 10 is a spiral pancake double layer winding.
  • the numbers indi­cate the winding sequence for electrical current flow in the direction of the solid arrow.
  • the independent and generally parallel flow paths of coolant are represented by the dashed arrows.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
EP88106742A 1987-05-15 1988-04-27 Bobine excitatrice discret produisant un étanchement dans une machine de coulée continue pour le tube de coulée avec buse de sortie et la transition d'entrée de moule Withdrawn EP0290866A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US5027287A 1987-05-15 1987-05-15
US50272 1987-05-15

Publications (2)

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EP0290866A2 true EP0290866A2 (fr) 1988-11-17
EP0290866A3 EP0290866A3 (fr) 1989-07-19

Family

ID=21964326

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EP88106742A Withdrawn EP0290866A3 (fr) 1987-05-15 1988-04-27 Bobine excitatrice discret produisant un étanchement dans une machine de coulée continue pour le tube de coulée avec buse de sortie et la transition d'entrée de moule

Country Status (6)

Country Link
EP (1) EP0290866A3 (fr)
JP (1) JPS63303664A (fr)
KR (1) KR880013641A (fr)
CN (1) CN88102828A (fr)
BR (1) BR8802312A (fr)
IN (1) IN168655B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103170593A (zh) * 2013-04-07 2013-06-26 昆明理工大学 一种连续制备金属半固态坯料的装置及应用
CN111974962A (zh) * 2019-09-19 2020-11-24 北京科技大学 一种表面增强梯度复合材料铸造设备和方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102019103895A1 (de) * 2019-02-15 2020-08-20 Tdk Electronics Ag Spule und Verfahren zur Herstellung der Spule

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0071802A2 (fr) * 1981-08-07 1983-02-16 Fried. Krupp Gesellschaft mit beschränkter Haftung Procédé et dispositif pour rendre étanche l'entre-espace entre parties en mouvement relatif
US4540037A (en) * 1982-09-27 1985-09-10 Concast Ag Method and apparatus for bidirectional horizontal continuous casing

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0071802A2 (fr) * 1981-08-07 1983-02-16 Fried. Krupp Gesellschaft mit beschränkter Haftung Procédé et dispositif pour rendre étanche l'entre-espace entre parties en mouvement relatif
US4540037A (en) * 1982-09-27 1985-09-10 Concast Ag Method and apparatus for bidirectional horizontal continuous casing

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103170593A (zh) * 2013-04-07 2013-06-26 昆明理工大学 一种连续制备金属半固态坯料的装置及应用
CN111974962A (zh) * 2019-09-19 2020-11-24 北京科技大学 一种表面增强梯度复合材料铸造设备和方法
CN111974962B (zh) * 2019-09-19 2022-02-22 北京科技大学 一种表面增强梯度复合材料铸造设备和方法

Also Published As

Publication number Publication date
KR880013641A (ko) 1988-12-21
JPS63303664A (ja) 1988-12-12
BR8802312A (pt) 1988-12-13
CN88102828A (zh) 1988-11-30
EP0290866A3 (fr) 1989-07-19
IN168655B (fr) 1991-05-18

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