EP0008376A1 - Procédé de coulée continue de métal dans une lingotière et action d'un champ électro-magnétique - Google Patents

Procédé de coulée continue de métal dans une lingotière et action d'un champ électro-magnétique Download PDF

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Publication number
EP0008376A1
EP0008376A1 EP19790102611 EP79102611A EP0008376A1 EP 0008376 A1 EP0008376 A1 EP 0008376A1 EP 19790102611 EP19790102611 EP 19790102611 EP 79102611 A EP79102611 A EP 79102611A EP 0008376 A1 EP0008376 A1 EP 0008376A1
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EP
European Patent Office
Prior art keywords
strand
thrust
phase
fields
phases
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
Application number
EP19790102611
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German (de)
English (en)
Other versions
EP0008376B1 (fr
EP0008376B2 (fr
Inventor
Jan Lipton
Carl-Ake Däcker
Armin Thalmann
Axel-Ingo Haefeker
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.)
SMS Concast AG
Original Assignee
Concast Holding AG
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.)
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Publication date
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First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=27172616&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0008376(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Priority claimed from CH813478A external-priority patent/CH632172A5/de
Priority claimed from CH102979A external-priority patent/CH635012A5/de
Priority claimed from CH118479A external-priority patent/CH635013A5/de
Application filed by Concast Holding AG filed Critical Concast Holding AG
Priority to AT79102611T priority Critical patent/ATE3250T1/de
Publication of EP0008376A1 publication Critical patent/EP0008376A1/fr
Publication of EP0008376B1 publication Critical patent/EP0008376B1/fr
Application granted granted Critical
Publication of EP0008376B2 publication Critical patent/EP0008376B2/fr
Expired 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
    • B22D11/12—Accessories for subsequent treating or working cast stock in situ
    • B22D11/122—Accessories for subsequent treating or working cast stock in situ using magnetic fields

Definitions

  • the present invention relates to a process for the continuous casting of metal, in which melt is poured into a mold, the resulting strand having a liquid core is drawn out, guided and further cooled, and a turbulent flow in the liquid core is induced by at least one stirrer inducing electromagnetic fields in the strand is produced.
  • the structure of a strand produced by the continuous casting process depends, among other things, on the composition of the material and the casting temperature. At casting temperatures of only a few degrees Celsius above the melting temperature, a globular, non-directional structure, and at casting temperatures with more than 15 ° above liquidus, a columnar, directed structure with a strong, central positive segregation of the accompanying elements. Must be cast in practice with overnight temperatures above 20 0 C for technical reasons,. For this reason, many efforts have already been made to obtain a slab with a predominantly globular, undirected structure and little central segregation even when continuously casting at such excess temperatures.
  • Alloy and accompanying elements such as C, Si, Mn, P, S etc. are contained in the steel, which can lead to segregation, especially central segregation, when solidified.
  • segregations, as well as the crystal structure are known to include depending on the level of excess temperature.
  • segregations are to be prevented by electromagnetic stirring or by the turbulent flow generated.
  • the solidification structure should be influenced in such a way that the largest possible zone of dense, undirected crystal structure is obtained.
  • the solidification front is influenced by the strong local movement of the melt in such a way that so-called white bands form. These white bands are negative segregations that can have a negative impact on quality.
  • a device is also known in which an electromagnetic device is provided around the mold tube is arranged three pairs of poles, which sets the liquid core in a rotating motion about the longitudinal axis of the strand.
  • This rotation created by a perfect rotating field, has an insufficient turbulence in its flow.
  • the mixing of the liquid steel is imperfect because there is no force acting transversely to the strand due to the uniform magnetic application of the melt.
  • This relatively low turbulence leaves something to be desired in terms of the quality of the cast product in relation to the surface, the distribution of the alloying and accompanying elements, but also to the internal structure.
  • thrust forces are generated in the direction of the longitudinal axis of the strand with an electromagnetic traveling field, the magnets running around the strand being arranged between the pairs of rollers up to the end of the sump.
  • the flow created along the swamp brings the desired area of non-columnar structure and prevents the occurrence of significant segregations, in particular the central sedimentation and white bands.
  • Such an arrangement requires too much space due to the large number of magnets, hinders sufficient cooling of the strand and is far too complex.
  • Another known method for slab formats attempts to eliminate these white strips by generating shear forces on the liquid steel with electromagnetic traveling fields, excited by two magnets located on the long sides opposite one another. These shear forces should act transversely to the longitudinal axis of the strand so that the flow is gently knocked against the solidified wall so that the deflected flow is kept within a limited range. This limited area of activity results in an insufficient zone of dense, undirected crystal structure. Furthermore, it has been shown that with this method the white strips can only be insufficiently eliminated, so that these disadvantages do not result in an optimal product, which can have a negative impact on the quality of the rolled product, for example.
  • the cast material should not have any white bands and should be low in segregation, particularly with regard to the central segregation.
  • a linear thrust direction can be generated in the melt transversely or longitudinally to the longitudinal axis of the strand from the differently acting thrust forces within the fields.
  • the space required to produce a stirring effect which is sufficiently long in the direction of the strand is therefore reduced.
  • the shear forces acting differently within the fields produce a shear direction in the melt that runs in an arc around the longitudinal axis of the strand.
  • the strand surface can be improved in addition to the better internal structure.
  • the windings of one phase in order to generate the different shear forces, can be acted upon by different current strengths compared to the windings of at least one other phase.
  • These different current strengths are advantageously in a range between approximately 10% and 25%.
  • the differently acting thrust forces can also be generated by different geometrical configurations of the phases.
  • the asymmetry in the phases in the starting period is set from approximately zero to a predetermined maximum value. It was thus possible to ensure that the foremost strand section also has the desired metallurgical quality.
  • Fig.l 1 denotes a cooled, curved and oscillating mold for casting a slab, which is supplied with liquid steel from a casting vessel, not shown, via a pouring tube reaching into the mold 1.
  • the strand 2 formed in the mold 1 and having a liquid core 3 is guided and supported in a curved strand path 4 following the mold 1 with a radius of 10 m with the aid of rollers 5.
  • Spray nozzles 6 are arranged between the rollers 5 for further cooling of the strand 2.
  • the strand is pulled out and straightened by a driving judge 7.
  • a stirrer in the form of a traveling field magnet 10 of known construction is arranged on the inside of the strand 4 at a distance of approximately 5 m below the end of the mold. Between the magnet 10 and the inside of the strand 2, rollers 5 'made of an anti-magnetic material, for example stainless steel, are attached.
  • the magnet 10 is constructed in two phases. Three-phase magnets can also be used. The shear forces generated by the stirrer act transversely to the longitudinal axis of the strand.
  • the slabs cast on the system described had a format of 1550 mm x 270 mm.
  • the pull-out speed was about 0.55 m / min.
  • Both phases were applied at a voltage of 200 V with a frequency of 2 Hz and approx. 1000 amperes, ie symmetrically.
  • 2 shows the micrograph of a steel cast at an excess temperature of 29 ° C. with 0.15% C, 0.025% S and the usual other Accompanying elements, whereby a conventional stirring method was used.
  • the micrograph shows a relatively thin edge zone 20 with a predominantly globulitic structure. This zone 20 is followed by a zone 21 with a columnar structure of dendrites directed towards the center.
  • Zone 21 is followed by zone 22, which has an undirected crystal structure, is lighter and represents a white band.
  • This band can consist of one piece, as the reference number 22 indicates, or can be divided into several bands 23, 24, 25.
  • the zone 22 is followed by a zone 26 with a dense, non-directional crystal structure, which merges into the central reduction 27.
  • FIG. 4 illustrates a micrograph of half the cross section of a slab stirred by the method according to the invention.
  • the format of the slab cross-section, steel quality, pull-out speed, direction of the shear forces and frequency were the same as described for Fig. 2.
  • the conversion temperature was 43 0 C.
  • the strength of the excitation current was for a phase A 830 and for the other phase 1000 amperes.
  • One phase is thus exposed to a current that is approximately 20% higher than the other phase, ie the phases of the electromagnetic fields are asymmetrical.
  • a zone 31 with a predominantly globulitic structure can again be seen in the micrograph. This is followed by a zone 32 with dendrites directed towards the center of the slab.
  • the middle of the slab has a zone 34 with a likewise undirected crystal structure, which is, however, finer and denser than that according to FIG. 2.
  • the running direction of the hiking field also has a decisive influence on the casting quality.
  • This can run from left to right or vice versa on a broad side of the slab.
  • the stirrer can be arranged on one or on both broad sides.
  • Asymmetry creates a natural shear force that is inherent and perpendicular to the main movement component and also perpendicular to the strand pulling direction.
  • the force resulting from the asymmetry in the phases and perpendicular to the stirrer surface should be effective away from the stirrer surface facing the strand.
  • their direction of action can be rotated by 180 °, i.e. away from the middle of the strand towards the strand skin.
  • the different shear forces are generated by applying different currents to the windings.
  • these different shear forces can also be achieved through different geometric configurations of the phases, e.g. of the number of turns.
  • the traveling field magnets can also be arranged so that the different shear forces act in the direction of the longitudinal axis of the strand or at an angle to it.
  • an additional hiking field can be provided on the other side of the strand. With strands with long liquid cores, more than one moving field can act in the longitudinal direction of the strand.
  • the turbulent flow can also be effective in the mold, the flow advantageously being held in such a way that it does not affect the bath level in order not to have a negative effect on the surface quality of the strand.
  • the asymmetry described can also be achieved by the interaction of several stirring segments in the same stirrer with different loading or geometric design of the phases.
  • an arcuate thrust direction producing a rotational movement of the melt about the longitudinal axis of the strand.
  • a mold consists of a K o-kill pipe 52 of copper and a Kokillenmantel 53.
  • a cooling jacket 54 is arranged to the tube 52. Cooling water flows through the space between the mold 52 and the cooling jacket 54.
  • a partially solidified strand 60 with a liquid core 61 is shown in the interior of the mold 52. This strand 60 is pulled out of the mold by known means and cooled further.
  • Magnetic poles 70, 71, 72, 73 are provided on each side of the cooling jacket 54, each of which is provided with a turn 74, 75, 76, 77. These magnetic poles are cooled by cooling water in the space between cooling jacket 54 and mold jacket 53. The turns 74, 75, 76, 77 are switched so that a traveling field is created. These magnetic poles form an electromagnetic field in the strand-inducing stirrer. Depending on the casting parameters, one phase is fed with a current that is 10 - 25% higher than the other, subsequent phase. For a billet of 100 x 100 mm, the turns 74 and 76 are loaded with 400 A at a frequency of 50 Hz and a voltage of 50 V and the turns 75 and 77 with 320 A.
  • the traveling field produces differently acting shear forces in the liquid steel which, due to the arrangement of the magnetic poles described, cause the melt to rotate. If deeper penetration of the stirring effect or a lower stirring speed is desired, the frequency is reduced accordingly, especially with large wall thicknesses of the mold tube.
  • the circuit can, however, also be selected such that the magnetic flux flows between the pole pairs 70, 72 or 71, 73 and the rotary movement is generated in this way with the aid of the magnetic field.
  • the pole pairs 70, 72 are excited, for example, with 400 A and the pole pairs 71, 73 with 320 A.
  • the number of poles can be increased for larger billet and bloom formats.
  • the differently acting thrust forces can be generated by different geometrical configurations of the phases, e.g. by different number of turns or by different formation of the pole irons, such as shape and size of the iron cross sections and / or polar axis directions etc.
  • the method according to the invention can be used for all types of continuous casting plants with continuous molds, also for plants for casting beam pre-profiles and non-ferrous metals. In the case of strands with long, liquid cores, several stirrers can work together.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
EP19790102611 1978-07-28 1979-07-24 Procédé de coulée continue de métal dans une lingotière et action d'un champ électro-magnétique Expired EP0008376B2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT79102611T ATE3250T1 (de) 1978-07-28 1979-07-24 Verfahren zum stranggiessen von metall in eine kokille und einwirkung eines elektromagnetischen feldes.

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
CH8134/78 1978-07-28
CH813478A CH632172A5 (en) 1978-07-28 1978-07-28 Method for the continuous casting of steel
CH102979A CH635012A5 (en) 1979-02-02 1979-02-02 Method for the continuous casting of steel
CH1029/79 1979-02-02
CH1184/79 1979-02-07
CH118479A CH635013A5 (en) 1979-02-07 1979-02-07 Method for the continuous casting of steel

Publications (3)

Publication Number Publication Date
EP0008376A1 true EP0008376A1 (fr) 1980-03-05
EP0008376B1 EP0008376B1 (fr) 1983-05-11
EP0008376B2 EP0008376B2 (fr) 1989-04-05

Family

ID=27172616

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19790102611 Expired EP0008376B2 (fr) 1978-07-28 1979-07-24 Procédé de coulée continue de métal dans une lingotière et action d'un champ électro-magnétique

Country Status (10)

Country Link
EP (1) EP0008376B2 (fr)
AR (1) AR217530A1 (fr)
AU (1) AU528461B2 (fr)
BR (1) BR7904814A (fr)
DD (1) DD145069A5 (fr)
DE (2) DE2965366D1 (fr)
DK (1) DK147553C (fr)
ES (1) ES483648A1 (fr)
FI (1) FI63682C (fr)
SE (1) SE440493B (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0051221A1 (fr) * 1980-10-30 1982-05-12 Concast Holding Ag Procédé pour la coulée d'acier en continu, notamment de brames
US4375830A (en) * 1980-03-20 1983-03-08 Concast Ag Method and apparatus for supporting a steel strand produced during a continuous strand casting method
EP0028761B1 (fr) * 1979-11-06 1985-02-20 Asea Ab Procédé de brassage lors de la coulée continue

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE410940C (sv) * 1978-04-05 1986-01-27 Asea Ab Forfaringssett for omroring vid strenggjutning
FR2530510B1 (fr) * 1982-07-23 1985-07-05 Cegedur Procede de coulee electromagnetique de metaux dans lequel on fait agir au moins un champ magnetique different du champ de confinement
AT378138B (de) * 1983-11-04 1985-06-25 Voest Alpine Ag Ruehreinrichtung an einer stranggiessanlage

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE6930213U (de) * 1969-07-28 1970-07-30 Mannesmann Ag Anordnung von wechselstromdurchflossenen spulen in einer brammen-stranggiessanlage
DE2720391A1 (de) * 1976-05-21 1977-12-01 Asea Ab Anordnung beim stranggiessen
DE2810876A1 (de) * 1977-03-14 1978-09-21 Arbed Verfahren und vorrichtung zum umruehren von im schmelzzustand befindlichen metallen waehrend des kontinuierlichen giessens von brammen

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE410940C (sv) * 1978-04-05 1986-01-27 Asea Ab Forfaringssett for omroring vid strenggjutning

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE6930213U (de) * 1969-07-28 1970-07-30 Mannesmann Ag Anordnung von wechselstromdurchflossenen spulen in einer brammen-stranggiessanlage
DE2720391A1 (de) * 1976-05-21 1977-12-01 Asea Ab Anordnung beim stranggiessen
DE2810876A1 (de) * 1977-03-14 1978-09-21 Arbed Verfahren und vorrichtung zum umruehren von im schmelzzustand befindlichen metallen waehrend des kontinuierlichen giessens von brammen

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
E. HERRMANN "Handbuch des Stranggiessens" 1958, Aluminium Verlag, Dusseldorf. * Seiten 417 bis 428 * *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0028761B1 (fr) * 1979-11-06 1985-02-20 Asea Ab Procédé de brassage lors de la coulée continue
US4375830A (en) * 1980-03-20 1983-03-08 Concast Ag Method and apparatus for supporting a steel strand produced during a continuous strand casting method
EP0051221A1 (fr) * 1980-10-30 1982-05-12 Concast Holding Ag Procédé pour la coulée d'acier en continu, notamment de brames

Also Published As

Publication number Publication date
EP0008376B1 (fr) 1983-05-11
FI63682B (fi) 1983-04-29
BR7904814A (pt) 1980-04-22
FI63682C (fi) 1983-08-10
DD145069A5 (de) 1980-11-19
FI792307A (fi) 1980-01-29
DE2930281A1 (de) 1980-02-14
DK317279A (da) 1980-01-29
AR217530A1 (es) 1980-03-31
SE440493B (sv) 1985-08-05
ES483648A1 (es) 1980-04-16
AU528461B2 (en) 1983-04-28
DE2930281B2 (de) 1981-06-04
SE7906413L (sv) 1980-01-29
DK147553B (da) 1984-10-01
AU4922079A (en) 1980-01-31
DE2965366D1 (en) 1983-06-16
DK147553C (da) 1985-03-04
EP0008376B2 (fr) 1989-04-05

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