EP0204685A1 - Procédé de coulée continue horizontale pour métaux à point de fusion élevé, en particulier de l'acier - Google Patents

Procédé de coulée continue horizontale pour métaux à point de fusion élevé, en particulier de l'acier Download PDF

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Publication number
EP0204685A1
EP0204685A1 EP86890125A EP86890125A EP0204685A1 EP 0204685 A1 EP0204685 A1 EP 0204685A1 EP 86890125 A EP86890125 A EP 86890125A EP 86890125 A EP86890125 A EP 86890125A EP 0204685 A1 EP0204685 A1 EP 0204685A1
Authority
EP
European Patent Office
Prior art keywords
strand
casting
metal
essentially
mold
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
EP86890125A
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German (de)
English (en)
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EP0204685B1 (fr
Inventor
Peter Dipl.-Ing. Machner
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.)
Boehler GmbH
Primetals Technologies Austria GmbH
Original Assignee
Vereinigte Edelstahlwerke AG
Boehler GmbH
Voestalpine AG
Voest Alpine Industrienlagenbau GmbH
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 Vereinigte Edelstahlwerke AG, Boehler GmbH, Voestalpine AG, Voest Alpine Industrienlagenbau GmbH filed Critical Vereinigte Edelstahlwerke AG
Publication of EP0204685A1 publication Critical patent/EP0204685A1/fr
Application granted granted Critical
Publication of EP0204685B1 publication Critical patent/EP0204685B1/fr
Anticipated expiration legal-status Critical
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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
    • 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
    • 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
    • B22D11/047—Means for joining tundish to mould

Definitions

  • the invention relates to a process for the horizontal continuous casting of, in particular higher melting metals, preferably steels.
  • a number of methods and devices for the horizontal continuous casting of higher-melting metals, such as especially steels, are known, all of which have in common that from a melt container containing the u-casting metal in the molten state, this is usually via a heat-resistant metal guide with a connecting element, e.g. Mouthpiece, under the action of its own hydrostatic pressure, flows into a substantially horizontally directed, shaping slide mold, preferably cooled with a cooling medium.
  • the metal stream is solidified to form a shell that grows inwards on all sides to form a metal strand that has a liquid metal core on the inside.
  • a trigger device e.g. pulled out of the mold with gripper rollers, after which further processing takes place.
  • each step or stroke is terminated in each case by a take-off speed minimum, a real standstill or even a slight reversal of the take-off direction, as a result of which the step-by-step formed pieces are welded together.
  • the metallurgical advantages of the horizontal casting process include in that even smaller strand cross-sections up to a diameter of a few mm can be produced, with no reoxidation of the pouring jet and thus deterioration in the degree of purity of the billet occurring.
  • a continuous casting device has become known from EU-A 117 067, in which a metal stream coming from the melt vessel in the melt guide, on the mouthpiece and in the mold has a practically constant cross-sectional area and, as shown there, by means of a magnetic coil in the area of the mold, a stirring movement about an axis is rotated transversely to the direction of the strand movement. Movement takes place there to microcavities and segregation to avoid the train, and to achieve related to the scope uniform solidification of the strand shell - This Be.
  • the stirring in said direction of the portion of the strand cross-sectional area of substantially a xialraineten crystals is substantially reduced.
  • the crystallization conditions for the steel in the area of the described artificial meniscus or tear-off ring require a strand movement according to the go and stop principle.
  • the solidification occurs not only on the mold wall, but also on the cooled tear-off ring, which or its end face acts as a meniscus.
  • a strand shell thickening builds up, ie a strand shell maximum that rises all the way to the strand axis.
  • liquid metal flows into the released mold area and solidifies again on the ring, on the mold surface and also on the rear front of the existing strand shell, which is essentially an "impression" of the end face of the casting ring.
  • the newly formed shell then joins or welds to those areas of the strand which, due to the cooling effect of the tear-off ring, solidified in a largely axial direction, i.e. where the thickness maximum occurs, the inhomogeneities known as lifting marks, in particular disturbances of radial crystallization are essentially from the strand withdrawal parameters and in particular from the period in which the metal solidifies on the tear-off ring and is influenced by the overheating of the incoming steel into the mold. Pronounced and deep lifting heights in stainless steel strands can lead to problems during further shaping, in particular to the surface fragility of the material.
  • the lifting marks caused by the tear-off ring are defects in the radial strand crystallization.
  • the newly formed shell has to be largely welded to those areas of the strand which, due to the cooling effect of the tear-off ring, solidify in a largely axial direction.
  • Both the formation and in particular the depth of the defects or lifting marks as well as the welding of the strand shells in these areas is reduced with increasing overheating of the steel above its liquidus temperature.
  • High steel overheating causes a deterioration in the inner quality of the strand, particularly in the case of stainless steels. In particular, this concerns crystallization, the formation of coarse cavities and the development of excessive segregation.
  • the above EU-A concerns the attempt to improve the internal quality of the billets by magnetic fields, which act on the solidifying strand at certain intervals.
  • the invention accordingly relates to a process for the horizontal continuous casting of, in particular higher-melting, metals, preferably steels, in which a metal melt located in a container communicates with at least one metal melt stream which is moved by at least one melt guide and subsequent, preferably cooled, shaping mold, which melt stream for its part beginning in an essentially mold, on all sides under image; a strand shell of increasing thickness becomes solidified, whereby the mold and the strand are gradually moved relative to one another, in particular the strand is gradually withdrawn, the liquid metal being additionally moved under the action of, preferably magnetic, fields, which essentially consists of that in a length (L) which can be defined in steps with the relative movement, in particular the strand draw, in a discontinuous relative movement, at a transition, preferably essentially not wettable with melt, from the melt guide into the mold, preferably pouring nozzle, pouring ring , or the like., a metal stream which is subjected to cross-sectional widening which extends essentially outwards on all
  • the metal melt coming from the melt container is at least slightly overheated and, as described above, the strand shell thickening which forms at the end of the stroke at the end of the casting ring melts again by targeted inflow from the tip thereof, and in this way breaks down the maximum. It is favorable, if the rotation movement of at least a bzugsdorf A induces time. It is essential to ensure that the liquid metal on the flow nozzle, e.g. a zirconium oxide or boron nitride ring, a magnetic rotating and / or ode, is arranged appropriately in or around the mold.
  • the liquid metal on the flow nozzle e.g. a zirconium oxide or boron nitride ring, a magnetic rotating and / or ode
  • rotating and / or traveling fields generated with electromagnets can be regulated and adjusted in any form to generate the rotating movement of the metal.
  • the movement of the melt provided according to the invention does not have the aim of increasing the quality of the interior of the strand, for example by reducing segregation or the like. Measures for this can only be taken later after the formation of more substantial thickness ranges of the strand shell come to fruition. With the purging of the maxima of the strand shell thickness achieved in accordance with the invention, a much more intimate welding of the strand shell piece just formed or its maximum pulled off from the casting ring during one stroke with the metal flowing in during the subsequent stroke can be achieved.
  • the liquid metal at least within the above-mentioned distance, in addition to the transverse, in particular rotational movement, in particular with an approximately linear vector, is displaced in an optionally oscillating movement essentially in the direction of the strand axis.
  • the liquid metal is displaced in an optionally oscillating movement essentially in the direction of the strand axis.
  • Such e.g. to the respective withdrawn strand shell maximum rear front, e.g. Movement directed in the direction of the strand movement can bring about a particularly intensive melting of the rear front of the solidified strand shell and thus a higher quality of the welding of the strand shell piece that has just solidified and is being formed.
  • a variant which is more complex in terms of control technology and which can essentially be achieved for example, by superimposing the rotary movement about the strand axis just mentioned with a movement which essentially produces fields in the strand axis direction, by means of magnetic field injection within a main axis which is essentially parallel to the strand axis and essentially has a toroidal enveloping surface and which is set in motion which rotates around the curved center line thereof, the toroidal enveloping surface itself also preferably being rotated about the strand axis.
  • Particularly effective washing of the strand shell maximum and the lifting rear of the strand shell can thus be achieved, since a kind of increased erosion occurs due to the rotating melt under pressure to the rear front.
  • the metal of the metal stream essentially only in the vicinity of a strand shell thickness maximum as described, preferably at least over a stripping step length, essentially on or in Beginning in the region of the metal flow cross-section-widening transition, essentially synchronously with the strand withdrawal speed or its discharge profile, a magnetic field, possibly oscillating and / or rotating movement essentially in the strand axis direction, is displaced about the strand axis.
  • a magnetic field possibly oscillating and / or rotating movement essentially in the strand axis direction
  • the metal of the melt stream is essentially within an inner distance from the strand axis, essentially up to the inside of the mold forming strand shell extending annular space in addition to movement with the strand withdrawal in transverse movement, in particular rotating movement is set.
  • CrNi steel (composition in% by weight: C 0.035, Si 0.55, Mn 1.05, Cr 18.32, Ni 9.81, balance Fe and steel impurities) was cast in a continuous casting plant with an oscillating strand.
  • the mold cross was 106 mm 2
  • the inlet cross section was pressed into the mold B ornitridringes was 80 mm 2 so that on the inner surface of the mold, a radial projection of the Abr consideringringes of 13 mm, where the.
  • the melt was cast at a speed of 2 m / min, the stroke length or the length of a draw-off step being 22.5 mm.
  • the casting was carried out in a two-strand HCC system, ie two molds were attached to a distributor, one mold being equipped with rotating magnetic field coils, which caused the melt to rotate around the strand axis over a distance of 50 mm beginning at the casting ring.
  • the temperature of the steel in the distributor loading ru t g 1475 0 C, which corresponds to an overheating of 20 ° C.
  • Metallographic examinations showed that the lifting marks of the strand pulled out of the mold in a conventional construction had a depth between 2.1 and 2.4 mm.
  • the stroke mark depth of the strand cast using the method according to the invention was max. 0.2 mm.
  • a two-strand HCC system was provided with a mold which corresponded to the prior art and which worked with a magnet coil inducing rotation of the melt.
  • Quenched and tempered steel with a temperature of 1550 ° C (overheating 48 ° C), (composition in% by weight: C 0.33, Si 0.28, Mn 0.52, Cr 1.45, Mo 0.22, Ni 1 , 52) was cast at a speed of 2 m / min and a stroke length of 22.5 mm per step.
  • the subsequent metallographic examination of the strands in comparison showed that the stroke mark depth of approximately 0.6 mm could still be reduced by using the method according to the invention with a 50 mm long melt rotation zone.
  • good surface quality was achieved for both billets.
  • the internal quality of bars rolled with a 6: 1 deformation was poor. Remains of cavities and strong segregations in the center area caused the material to be allocated to the committee.
  • the strand produced by the process according to the invention could be deformed without any problems, the rod material rolled out of the strand with a degree of deformation of 5.1: 1 showed no surface defects or increased roughness, which originates from the lifting marks.
  • the internal quality of the bars was good; due to the lower overheating, a good structure, dense center of the bars and low local Seiger degrees were found.
  • the method according to the invention in horizontal continuous casting can therefore produce billets with good surface quality even with slight overheating of the steel above its liquidus temperature, which is an essential prerequisite for achieving high-quality internal strand zones.
  • FIG. 1 schematically shows an oblique view of the cut-open inlet area of a horizontal casting mold with the rotary movement of the metal according to the invention
  • FIG. 2 shows a sectional view of this area with the strand being formed.
  • the melt reaches the mold as a metal stream 5 from a melt container, not shown, through a feed line (1) with a casting ring (2), for example made of BN, which projects into the shaping slide mold 4 with cooling channels 41.
  • a casting ring (2) for example made of BN
  • the wall 42 in cooling follows the formation of a shell (50) of solidified metal, which, in the direction r of the deduction of thickness s, finally merges into a hardened metal strand, not shown, which is intermittently pulled out of the mold 4 with a stroke length 1.
  • a circumferential strand shell thickness 51 solidifies on the mold-side end face 21 of the casting ring 2.
  • Fig. 2 shows the conditions at the inlet area of the mold 4 in section.
  • the flow of the melt 5 passes through the feed 1 made of refractory material, the end of which has a pouring nozzle 2, which projects into the mold 4 with cooling chambers 41, in the direction r of the strand withdrawal into the mold 4.
  • the liquid metal 5 is set into a rotating movement d about the axis a of the strand, wherein, as indicated by a dash-dotted line, the peak of the maximum of the shell thickness 51a at least along the withdrawal distance of a withdrawal length l of the previous stroke and the maximum 51 that is currently being formed are continuously prevented from forming and growing by flushing with hot molten metal, at the same time intensive contact of the rear side 53 of the strand shell section formed during the previous stroke and thus intimate welding.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
EP19860890125 1985-05-07 1986-05-05 Procédé de coulée continue horizontale pour métaux à point de fusion élevé, en particulier de l'acier Expired - Lifetime EP0204685B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT136485A AT394816B (de) 1985-05-07 1985-05-07 Verfahren zum horizontalen stranggiessen von, insbesondere hoeher schmelzenden, metallen, vorzugsweise staehlen
AT1364/85 1985-05-07

Publications (2)

Publication Number Publication Date
EP0204685A1 true EP0204685A1 (fr) 1986-12-10
EP0204685B1 EP0204685B1 (fr) 1990-07-25

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Application Number Title Priority Date Filing Date
EP19860890125 Expired - Lifetime EP0204685B1 (fr) 1985-05-07 1986-05-05 Procédé de coulée continue horizontale pour métaux à point de fusion élevé, en particulier de l'acier

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Country Link
EP (1) EP0204685B1 (fr)
JP (1) JPS61255748A (fr)
AT (1) AT394816B (fr)
DE (1) DE3672903D1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2122516A1 (fr) * 1971-01-19 1972-09-01 Davy Ashmore Ltd
EP0087950A1 (fr) * 1982-02-27 1983-09-07 KABUSHIKI KAISHA KOBE SEIKO SHO also known as Kobe Steel Ltd. Procédé de brassage électromagnétique à l'intérieur d'un moule en coulée continue horizontale et appareil pour le brassage
EP0117067A1 (fr) * 1983-01-20 1984-08-29 KABUSHIKI KAISHA KOBE SEIKO SHO also known as Kobe Steel Ltd. Procédé de brassage électromagnétique en coulée continue horizontale

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1558217A1 (de) * 1967-04-22 1970-03-19 Demag Ag Verfahren zum waagerechten Giessen von Metallen,insbesondere Stahl,und Stranggiessanlage zur Durchfuehrung des Verfahrens
DE1558224C3 (de) * 1967-06-24 1973-12-06 Theodor Prof. Dr.-Ing. 3000 Hannover-Kirchrode Rummel Verfahren und Vorrichtung zum horizontalen Stranggießen von schmelz flussigen Metallen, insbesondere Stahl
CH604974A5 (fr) * 1976-12-17 1978-09-15 Concast Ag

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2122516A1 (fr) * 1971-01-19 1972-09-01 Davy Ashmore Ltd
EP0087950A1 (fr) * 1982-02-27 1983-09-07 KABUSHIKI KAISHA KOBE SEIKO SHO also known as Kobe Steel Ltd. Procédé de brassage électromagnétique à l'intérieur d'un moule en coulée continue horizontale et appareil pour le brassage
EP0117067A1 (fr) * 1983-01-20 1984-08-29 KABUSHIKI KAISHA KOBE SEIKO SHO also known as Kobe Steel Ltd. Procédé de brassage électromagnétique en coulée continue horizontale

Also Published As

Publication number Publication date
JPS61255748A (ja) 1986-11-13
DE3672903D1 (de) 1990-08-30
AT394816B (de) 1992-06-25
EP0204685B1 (fr) 1990-07-25
ATA136485A (de) 1991-12-15

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