EP3134220B1 - Method and device for thin-slab strand casting - Google Patents
Method and device for thin-slab strand casting Download PDFInfo
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- EP3134220B1 EP3134220B1 EP15716054.0A EP15716054A EP3134220B1 EP 3134220 B1 EP3134220 B1 EP 3134220B1 EP 15716054 A EP15716054 A EP 15716054A EP 3134220 B1 EP3134220 B1 EP 3134220B1
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Images
Classifications
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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
-
- 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
-
- 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
- B22D11/103—Distributing the molten metal, e.g. using runners, floats, distributors
-
- 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
- B22D11/16—Controlling or regulating processes or operations
-
- 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
- B22D11/16—Controlling or regulating processes or operations
- B22D11/20—Controlling or regulating processes or operations for removing cast stock
Definitions
- the present invention is based on a method for thin-slab continuous casting according to the preamble of claim 1.
- a metallic melt is produced, which is transferred by means of a steel ladle in a distributor. From the distributor, the metallic melt flows via a pouring tube into a mold, which is moved in a cooled and oscillating manner. In the mold, a strand is formed from the metallic melt with a solidified shell and a largely not yet solidified cross-section within the solidified shell. When leaving the mold, the strand is taken up by a transport system with a plurality of strand guide rollers, between which the strand is passed through the so-called pouring arc and is cooled to complete solidification.
- EBR Electromagnetic Brake
- the mold For the production of thin slabs with thicknesses between 40 to 120 millimeters, the mold typically has a funnel-shaped enlarged cross section in the upper part and a rectangular cross section in the lower part. Due to these small thicknesses, the solidification times in thin-slab continuous casting are comparatively short and the proportion of liquid melt in the interior of the partially solidified strand is low. This inevitably results in a coarse, strictly directed, columnar structure in the continuous casting of thin slabs. However, such a structure may adversely affect the surface and interior condition of the products made from the thin slabs.
- an apparatus for casting metal which comprises a mold for forming a cast strand and means for supplying a primary flow of hot metallic melt to the mold.
- the device in this case has a magnetic device which applies a static or periodic magnetic field to the flow of the metal in the non-solidified parts of the cast strand to act on the molten metal in the mold during casting. In this way, the flow of the hot metal is to be braked and split to achieve a secondary flow pattern in the mold.
- Out DE 195 42 211 A1 is an electromagnetic stirring device for slab casting molds known by means of which the flow rate of the melt can be slowed down in the mold.
- Out JP 2003-326339 A is a method for continuous casting of thin slabs is known, in which the currents are influenced in the mold by a nearly U-shaped electromagnetic field is applied to the dip tube.
- the particular difficulty is to achieve a significant microstructural refinement in the case of the through-solidification times which are short compared to thick-slab continuous casting and the small-volume liquid fraction in the strand interior.
- the present invention solves this problem.
- a method for thin slab continuous casting comprising the steps of: supplying a metallic melt into a mold, forming a partially solidified thin slab strand from the metallic melt in the mold, reducing the flow rate of the metallic melt in partially solidified thin slab strand by means of a in the region of the mold arranged electromagnetic brake (EMBR) and discharging the partially solidified thin slab strand from the mold by means of a strand guide system, non-solidified parts of the partially solidified thin slab strand are stirred by means along the strand withdrawal direction of the thin slab downstream downstream of the mold arranged electromagnetic stirrer, wherein by means of the electromagnetic stirrer an electromagnetic traveling field in a along the strand withdrawal direction between 20 and 7,000 millimeters from the mold removed area de s thin slab strand is generated.
- EMBR electromagnetic brake
- the device according to the invention has the advantage over the prior art that a design for electromagnetic stirring designed for thin-slab casting achieves a refinement of the solidification structure in the interior of the thin slab strand and the simultaneous use of an electromagnetic brake prevents the flow induced by the agitator Increasing the flow velocity of the molten steel in the mold area to impermissibly strong local BadLiteschwankept, ie to BadLiteschwankept of, for example, more than 15 mm leads. High turbulence at the bath level can lead to strand breakthroughs or strand surface defects due to casting slag trapped at the bath level of the mold. Both strand breaks and strand surface defects should be avoided.
- the expansion of the globulitic core zone in the thickness direction is then in particular at least 30%.
- longitudinal streaks, microstructures, core segregations and internal cracking susceptibilities may occur reduced and the HIC resistance and the homogeneity of the mechanical and magnetic properties are increased.
- an electromagnetic traveling field is generated in a region of the thin slab strand which is removed from the mold along the strand withdrawal direction between 20 and 7,000 millimeters.
- a region of the thin slab strand which is between 20 and 7,000 millimeters from the mold is to be understood in particular as that region of the thin slab strand which has a distance of between 20 and 7,000 millimeters from the base of the mold.
- the position of the electromagnetic stirrer and the electromagnetic traveling field relative to the mold could also over the distance to the bath level in the mold be defined, which is typically located about 100 millimeters below the mold top.
- the electromagnetic stirrer is arranged such that the traveling field acts immediately below the mold on the not yet solidified parts of the strand, since a positive effect on the grain structure in already solidified parts of the strand by the traveling field is no longer possible.
- the electromagnetic traveling field is generated in a region along the strand withdrawal direction between 50 and 3,000 millimeters away from the mold or from the bottom of the mold. It is also conceivable to define the position of the electromagnetic stirrer or of the electromagnetic alternating field along the strand withdrawal direction over the distance to the bath level in the mold:
- the distance to the bath level along the strand withdrawal direction preferably comprises between 0.9 and 3.8 meters and preferably between 1 , 5 and 2.5 meters.
- a single electromagnetic stirrer is arranged on one side of the thin slab strand, either on the fixed side or the loose side, or a separate electromagnetic stirrer is arranged on each side, ie both on the fixed side and on the loose side ,
- that broad side of the strand guide segments is referred to as the fixed side, which always remains unchanged in its position and serves as a so-called reference line. Adjustments to the strand thickness formats are then always made on the opposite lot side.
- the process according to the invention is used in particular for the production of thin slabs in the continuous casting process and hot strip or cold strip produced therefrom.
- a thin slab in the sense of the present invention comprises in particular a slab with a thickness of between 40 and 120 millimeters.
- the first transverse direction is always perpendicular to the strand withdrawal direction and parallel to the strand surface normal of the slab broadside, while the second transverse direction is always perpendicular to the strand withdrawal direction and parallel to the strand surface on the slab broadside.
- the broad slab side is that side of the rectangular cross-section of the thin slab strand to understand, which has the greater extent.
- the first and the second transverse direction thus both run perpendicular to the strand withdrawal direction, and perpendicular to each other.
- the non-solidified parts within the mold and / or during the discharge of the partially solidified thin slab strand from the mold through the strand guide system by means of the electromagnetic stirrer, which is positioned below the mold, are stirred.
- this ensures that during stirring the proportion of not yet solidified molten metal inside the thin slab strand is still sufficiently large, i. at least 50% of the strand thickness is to obtain a cross-section as large as possible core zone with fine-grained, globulitic structure, d. H. to obtain a globulitic core zone having a thicknesswise extension of the slab of at least 30%.
- the electromagnetic stirrer is adjusted such that the electromagnetic traveling field along a second transverse direction, which is perpendicular to the strand withdrawal direction and parallel to a strand surface on a broad side of the thin slab strand, from a first edge region of the thin slab strand to a first edge region opposite the second edge region of the thin slab strand runs.
- a stirring of the not yet solidified metallic melt in the thin slab strand is achieved, so that form on solidification, fine, globulitic grains in the solidification structure.
- the electromagnetic traveling field is preferably reversed after a time span of 1 to 60 seconds, particularly preferably between 1 and 10 seconds, so that the electromagnetic traveling field subsequently runs along the second transverse direction from a second edge region of the thin slab strand to the first edge region of the thin slab strand. After a lapse of the period of 1 to 60 seconds, preferably again 1 to 10 seconds, the traveling electromagnetic field is reversed again and the cycle begins again.
- a bidirectional, symmetrical traveling electromagnetic field across the width of the thin slab strand is generated by means of the electromagnetic stirrer, wherein the electromagnetic stirrer is adjusted so that a first subfield of the electromagnetic traveling field from the center of the thin slab strand to a first edge region of the thin slab strand runs and that a second subfield of the electromagnetic traveling field from the center to a second edge region of the thin slab strand opposite the first edge region runs. It is preferred this electromagnetic traveling field 1 to 60 seconds, more preferably held between 1 and 10 seconds. Thereafter, the electromagnetic traveling field generated by the electromagnetic stirrer and thus the direction of the two subfields are reversed.
- This reverse electromagnetic traveling field is also preferably maintained between 1 to 60 seconds, and more preferably between 1 and 10 seconds. Thereafter, the traveling electromagnetic field is reversed again and the cycle starts again.
- This preferred embodiment ensures a symmetrical stirring of the not yet solidified metallic melt within the already solidified edge zone of the thin slab strand, so that a symmetrical solidification structure with fine, globulitic grains is formed.
- a bidirectional, symmetrical traveling electromagnetic field is generated across the width of the thin slab strand by means of the electromagnetic stirrer, wherein the electromagnetic stirrer is adjusted such that a first subfield of the electromagnetic traveling field from a first edge region of the thin slab strand runs to the center of the thin slab strand and that a second sub-field of the electromagnetic traveling field from a first edge region opposite the second edge region of the thin slab strand runs to the center of the thin slab strand.
- this electromagnetic traveling field is held for 1 to 60 seconds, in particular between 1 and 10 seconds. Thereafter, the electromagnetic traveling field generated by the electromagnetic stirrer and thus the direction of the two subfields are reversed.
- This reverse electromagnetic traveling field is also held between 1 to 60 seconds, in particular between 1 and 10 seconds. Thereafter, the traveling electromagnetic field is reversed again and the cycle starts again.
- This preferred embodiment also ensures a symmetrical stirring of the not yet solidified metallic melt within the already solidified edge zone of the thin slab strand, so that a symmetrical solidification structure with fine, globulitic grains is formed.
- an electromagnetic traveling field is generated across the width of the thin slab strand whose magnetic flux density averages preferably 0.1 to 0.6 Tesla, particularly preferably 0.3 to 0, 5 Tesla and most preferably substantially 0.4 Tesla. It has been found that an alternating field with amplitudes in the range of preferably 0.1 to 0.6 Tesla, more preferably 0.3 to 0.5 Tesla and most preferably substantially 0.4 Tesla sufficient to achieve an accelerated and uniform overheating degradation in the metallic melt.
- This effect is advantageously achieved by an electromagnetic stirrer set in such a way that the flow rate of the non-solidified parts in the partially solidified thin slab strand is at most 0.7 meters per second or at least 0.2 meters per second, and preferably between 0.2 and 0.7 meters per second Second lies.
- the associated circulation of the non-solidified parts in the thin slab strand ensures the accelerated and uniform reduction of overheating and thus for the desired microstructural refinement, without having to choose a lower overheating from the outset, through which the risk of immersion tube additions would increase dramatically.
- the electromagnetic stirrer is adjusted such that the stirring frequency is at least 0.1 Hz or at most 10 Hertz, and preferably between 1 and 10 Hz. It has been shown that this stirring frequency range is particularly advantageous. At a stirring frequency less than 0.1 Hz is no electromagnetic traveling field, so that no stirring effect occurs. If the stirring frequency is greater than 10 Hz, then the penetration depth of the electromagnetic traveling field in the strand interior is too low and no structural refinement is achieved.
- an electromagnetic field is generated within the mold whose magnetic flux density preferably 0.1 to 0.3 Tesla, more preferably 0.15 to 0.25 Tesla and all more preferably substantially 0.2 tesla.
- the flow velocity of the metallic melt between the partially solidified edge regions of the strand is thereby braked, thus preventing pouring mirror fluctuations, as well as surface defects resulting from pouring mirror fluctuations (so-called shell defects) and internal defects (for example, slag inclusions).
- the magnetic field strengths of the electromagnetic traveling field caused by the electromagnetic stirrer and of the field caused by the electromagnetic brake are matched to one another. It has been found that a tuning of the magnetic field strengths of the traveling electromagnetic field caused by the electromagnetic stirrer and the field caused by the electromagnetic brake is advantageous.
- the vote is preferably carried out by When the electromagnetic stirrer is energized, the magnetic field strength of the electromagnetic brake field is increased by 20 to 80% of its basic value to values between 0.1 and 0.3 Tesla.
- the basic value in this context is the magnetic field strength of the field of the electromagnetic brake, as is typically used without the additional use of an electromagnetic stirrer.
- Typical basic settings for an electromagnetic brake without the use of an electromagnetic stirrer are fields with magnetic field strengths between 0.08 and 0.2 Tesla.
- a device for thin slab continuous casting in particular using the method according to the invention, which comprises a supply means for supplying a metallic melt, a mold for forming a partially solidified thin slab strand from the metallic melt, one in the An electromagnetic brake for reducing the flow rate of the metallic melt inside the teilerstarrten strand within the mold and a strand guide system for discharging the partially solidified thin slab strand from the mold, wherein the device further comprises a along the strand withdrawal direction of the thin slab downstream downstream of the mold arranged electromagnetic stirrer for Stirring of non-solidified parts of the partially solidified thin slab strand, wherein the electromagnetic stirrer along the strand Abzu gsplatz between 20 and 7,000 millimeters from the mold is spaced.
- the device according to the invention has the advantage over the prior art that the metallic melt is stirred by the electromagnetic stirrer during the continuous casting, whereby a refinement of the solidification microstructure in the interior of the thin slab strand is achieved.
- the stirring of the metallic melt provides for an accelerated and uniform overheating degradation, which advantageously results in the formation of a core zone with a fine-grained, globulitic structure inside the thin slab strand, while coarse columnar crystalline structures are broken up by the agitation.
- the electromagnetic stirrer in particular generates a spatially and / or temporally variable magnetic field in the region of the thin slab strand.
- the electromagnetic stirrer preferably comprises a linear-field stirrer, which is arranged on one of the two broad sides of the thin-slab strand. It would also be conceivable, however, that a respective linear field stirrer is arranged on both opposite broad sides of the thin slab strand.
- the electromagnetic stirrer comprises a rotary field stirrer or a helicoidal stirrer.
- the electromagnetic stirrer is disposed along the strand take-off direction of the thin slab strand below the electromagnetic brake.
- a rapid and uniform reduction of overheating is thus achieved in the not yet solidified parts of the thin slab before the solidification progresses into the interior of the thin slab strand, so that the refinement of the solidification microstructure is achieved.
- the proportion of the globulitic core zone in the thin slab is greater, the closer the electromagnetic stirrer is arranged on the meniscus of the thin slab strand or on the bath mirror.
- the electromagnetic stirrer for this purpose should advantageously be arranged along the strand withdrawal direction 20 to 7,000 millimeters and preferably 50 to 3,000 millimeters from the mold and in particular from the lower mold side.
- the distance between the electromagnetic stirrer and the bath mirror preferably comprises between 0.9 and 3.8 meters and preferably between 1.5 and 2.5 meters.
- the electromagnetic stirrer 20 to 1000 millimeters, preferably 20 to 200 millimeters and more preferably 20 to 40 millimeters from a surface of the thin slab strand is spaced along the first transverse direction.
- the device according to the invention is used in particular for the production of thin slabs in the continuous casting process and hot strip or cold strip produced therefrom.
- the hot strip or cold strip is used in particular for the production of electrical sheets (not grain-oriented or grain-oriented) or sheets of higher-strength steels with yield strength values greater than 400 megapascals (for example tempered steel).
- a thin slab in the sense of In particular, the present invention includes a slab having a thickness of between 40 to 120 millimeters.
- the electromagnetic stirrer comprises a linear field stirrer for generating an electromagnetic traveling field in the region of the thin slab strand, wherein the traveling direction of the electromagnetic traveling field is aligned parallel to the second transverse direction.
- the electromagnetic stirrer is configured such that a first subfield of the traveling electromagnetic field travels from the center of the thin slab strand to a first edge region of the thin slab strand and a second subfield of the traveling electromagnetic field travels from the center to a second edge region of the thin slab strand opposite to the first edge region.
- This electromagnetic traveling field is held between 1 and 60 seconds, preferably between 1 and 10 seconds.
- the electromagnetic stirrer is adjusted such that the flow velocity of the metallic melt produced by the stirrer is at least 0.2 meters per second or at most 0.7 meters per second, and in particular between 0, 2 to 0.7 meters per second.
- the flow velocity of the metallic melt produced by the stirrer is at least 0.2 meters per second or at most 0.7 meters per second, and in particular between 0, 2 to 0.7 meters per second.
- the flow rate should not be less than 0.2 meters per second, because otherwise sufficient structural refinement can not be achieved.
- a globulitic core zone can not be considered sufficient. whose thickness expansion is less than 30%.
- the flow rate should also be no greater than 0.7 meters per second to avoid depletion of the melt on alloying elements in the region of the solidification front.
- the depletion of the melt on alloying elements in the area of the solidification front can be measured in the solidified material. This phenomenon is called "white bands" or "white stripes”. White bands lead to inhomogeneous properties of the final product.
- the electromagnetic brake in the upper half of the mold 20 to 150 millimeters, preferably 25 to 100 millimeters and particularly preferably substantially 75 millimeters from a surface of the thin slab strand along the first transverse direction is spaced .
- the aforementioned distance is to be understood in particular to mean the smallest distance between the electromagnetic brake and the strand surface.
- FIG. 2 is a schematic cross-sectional view of an apparatus 1 for producing thin slabs in the continuous casting method according to an exemplary embodiment of the present invention.
- metallic melt 2 is transferred from a steel ladle 6 into a distributor 3 and poured from the distributor 3 via a pouring tube 4 (feeding means) into a mold 5 of the device 1.
- the flow through the pouring tube is controlled in dependence on the pouring mirror 7 in the mold 5 with a stopper 8 or a slider.
- the mold 5 comprises a mold having a downwardly open passage opening with a rectangular cross-section.
- the broad sides 28 of the mold are spaced between 40 and 120 millimeters apart so that the mold 5 is suitable for casting thin slabs.
- the mold consists of water-cooled copper plates, which cause a solidification of the supplied metallic melt in the edge region of the mold 5.
- the mold 5 oscillates, thus adhering the strand surface to the mold 5 is prevented.
- the thin slab strand 9 passes through the mold 5 along a vertical strand withdrawal direction 15.
- the thin slab strand 9 is taken up by a transport system 12 (also referred to as a strand guiding system) with a plurality of strand guide rollers 13 and passed through a so-called pouring arc 14.
- the thin slab strand 9 is cooled until complete solidification.
- a first transverse direction 18 and a second transverse direction 30 are in FIG FIG. 1 outlined.
- the first transverse direction 18 in this case runs perpendicular to the strand withdrawal direction 15 and parallel to a strand surface normal of the slab broadside 28 (the slab broadside 28 protrudes FIG. 1 in the plane of the drawing), while the second transverse direction 30 is perpendicular to the strand withdrawal direction 15 and parallel to the strand surface on the broad slab side 28, ie, perpendicular to the first transverse direction 18 extends.
- an electromagnetic brake 16 (EMBR: Electromagnetic Brake) is arranged, which slows down the flow velocity of the metallic melt 2 inside the already partially solidified thin slab strand 9 and thus reduces Badadorschwankept in the mold 5.
- the electromagnetic brake In the present example, FIG. 16 includes two coils arranged on both sides of the thin slab strand 9.
- the electromagnetic brake 16 an electromagnetic field is generated within the mold 5, the magnetic flux density is preferably 0.1 to 0.3 Tesla and more preferably substantially 0.2 Tesla.
- the device 1 below the mold 5, the device 1 according to the invention comprises an electromagnetic stirrer 17 for stirring non-solidified parts of the partially solidified thin slab strand 9.
- the electromagnetic stirrer 17 comprises a linear-field stirrer which extends along one of the two broad sides 28 of the strand.
- the Linearfeldrrocker generated across the width of the thin slab strand 9 an electromagnetic traveling field 19 (see FIGS. 2a and 2b ) which cyclically reciprocates between a first edge region 20 of the thin slab strand 9 and an opposite second edge region 21 of the thin slab strand 9 along a second transverse direction 30 that is perpendicular to the strand withdrawal direction 15 and parallel to the broad side 28 of the strand surface.
- the traveling electromagnetic field 19 is generated in a region along the strand withdrawal direction 15 between 20 and 7,000 millimeters, preferably between 50 and 3,000 millimeters, away from the mold 5 and from the mold bottom 29 and comprises on average a magnetic flux density between 0.1 to zero , 6 Tesla and preferably of substantially 0.4 Tesla.
- the electromagnetic traveling field leads to a stirring of the metallic melt, whereby an accelerated and uniform overheating degradation is effected in the metallic melt. This advantageously leads to the formation of a larger core zone with a fine-grained, globulitic microstructure in the interior of the thin slab strand 9, while coarse column-crystalline structures are restricted by the electromagnetic stirring.
- an electromagnetic stirrer 17 set in such a way that the flow rate of the non-solidified parts in the partially solidified thin slab strand is less than 0.7 meters per second and preferably between 0.2 and 0.7 meters per second.
- the fine-grained, globulitic core zone then forms in the solidification structure, whereby the formation of columnar crystals between the edge zone and the center region of the thin slab strand 9 is suppressed.
- thin slabs are produced in particular for hot strip or cold strip.
- the hot strip or cold strip is used in particular for the production of electrical sheets (non-grain oriented or grain oriented) or sheets of higher strength steels with yield strength values greater than 400 megapascals (eg tempered steel).
- FIGS. 2a and 2b are schematic detail views of the device 1 for thin slab continuous casting in the mold and below the mold according to the above with reference to FIG. 1 illustrated exemplary embodiment of the present invention.
- a sectional image view is illustrated along a sectional plane parallel to the strand withdrawal direction 15 and parallel to the second transverse direction 30.
- a sectional view along a direction perpendicular to the strand withdrawal direction 15, ie perpendicular to the first transverse direction 18 and the second transverse direction 30 sectional image plane in the region of the electromagnetic stirrer 17 is illustrated, which corresponds to the cross section of the strand 9.
- the supply means comprises the pouring tube 4, which dips into the metallic melt 2 located in the mold 5, and spout holes 22 formed in the lower part of the pouring tube 4 below the pouring mirror 7 on the pouring tube 4.
- the metallic melt 2 is introduced by means of the spout holes 22 at an angle to the strand withdrawal direction 15 of the thin slab strand 9 (see flow arrows 23).
- the electromagnetic stirrer 17, which is arranged below the mold 5, generates below the mold 5, the electromagnetic traveling field 19, which in turn causes currents that can reach into the mold 5 - possibly even up to the bath level.
- the electromagnetic stirrer 17 is configured such that the traveling electromagnetic field 19 comprises two subfields, a first subfield 24 and a second subfield 25.
- the first sub-field 24 of the traveling electromagnetic field 19 cycles between a center 26 of the thin slab strand 9 and the first edge region 20 of the thin slab strand 9, while the second sub-field 25 of the traveling electromagnetic field 19 cyclically between the center 26 and the second edge region 21 of the thin slab strand 9 wanders back and forth.
- the movement of the electromagnetic traveling field 19 is represented schematically by the movement arrows 27.
- the division of the electromagnetic traveling field 19 into two bidirectional, symmetrical subfields leads to a uniform and symmetrical flow in the interior of the thin slab strand 9 and thus also to a rapid and uniform removal of the overheating.
- the electromagnetic stirrer 17 is preferably further adjusted such that the flow velocity of the metallic melt generated by the stirrer at the solidification front is between 0.2 to 0.7 meters per second.
- the electromagnetic stirrer 17 must be set such that the currents generated in the metallic melt 2 by the electromagnetic stirrer 17 do not lead to increased bath level fluctuations and not to increased local bath level elevations in the mold 5. In this case, the magnetic field strengths of the electromagnetic stirrer 17 and the electromagnetic brake 16 should be matched to one another.
- the tuning takes place, for example, by raising the magnetic field strength of the electromagnetic brake 16 by 20 to 80% of its basic value to values between 0.1 and 0.3 Tesla when the electromagnetic stirrer 17 is switched on.
- the basic value in this context is the magnetic field strength of the electromagnetic brake 16, as is typically used without the additional use of an electromagnetic stirrer 17.
- Typical basic settings for an electromagnetic brake 16 without the use of an electromagnetic stirrer 17 are 0.08 to 0.2 Tesla.
- FIG. 2a In the lower part of FIG. 2a is the rectangular cross-section of the passage opening of the mold 5 can be seen schematically.
- the electromagnetic traveling field 19 or the two subfields 24, 25 migrate along the broad sides 28 through the thin slab strand 9.
- the traveling electromagnetic field 19 is not divided into two sub-fields 24, 25, but runs along the second transverse direction 30 cyclically between the first edge region 20 of the thin slab strand 9 and the opposite second edge region 21 of the thin slab strand 9 back and forth.
- This embodiment is exemplary in FIG FIG. 2b illustrated.
- GCC globulitic core zone
- the test series prove that by adding an electromagnetic stirrer arranged below the mold, the proportion of the globulitic core zone (GKZ) increases from 0 to 10 percent to a proportion of 40 to 60 percent.
- the share of the globulitic core zone should be at least 30 percent and preferably greater than 50 percent. Overheating of less than 20 K is to be avoided, however, as problems would otherwise occur in the form of clogging of the dip tubes in the mold, which may result in strand surface defects or even strand breakthroughs.
- the distance between the mold or the base of the mold and the electromagnetic stirrer is thus advantageously between 20 and 7,000 millimeters and preferably between 50 and 3,000 millimeters.
- a distance between 100 and 7,000 millimeters, between 500 and 6,500 millimeters, between 700 and 6,300 millimeters, between 700 and 4,400 millimeters or between 700 and 2,800 millimeters is particularly advantageous.
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Description
Die vorliegende Erfindung geht aus von einem Verfahren zum Dünnbrammen-Stranggießen nach dem Oberbegriff des Anspruchs 1.The present invention is based on a method for thin-slab continuous casting according to the preamble of
Es ist aus dem Stand der Technik allgemein bekannt, Dünnbrammen im Stranggussverfahren herzustellen. Hierbei wird eine metallische Schmelze erzeugt, welche mittels einer Stahlgießpfanne in einen Verteiler überführt wird. Von dem Verteiler fließt die metallische Schmelze über ein Gießrohr in eine Kokille, welche gekühlt und oszillierend bewegt wird. In der Kokille bildet sich aus der metallischen Schmelze ein Strang mit einer erstarrten Schale und einem großenteils noch nicht erstarrten Querschnitt innerhalb der erstarrten Schale. Beim Verlassen der Kokille wird der Strang von einem Transportsystem mit einer Vielzahl von Strangführungsrollen aufgenommen, zwischen welchen der Strang durch den sogenannten Gießbogen geführt wird und bis zur vollständigen Durcherstarrung abgekühlt wird. Es ist ferner bekannt, die Strömungsgeschwindigkeit der metallischen Schmelze im Inneren des bereits teilerstarrten Strangs innerhalb der Kokille mittels einer elektromagnetischen Bremse (EMBR: Electromagnetic Brake) zu verlangsamen. Hierbei ist das Ziel, die Strömungsgeschwindigkeit der Stahlschmelze am Badspiegel zu verringern und das Badspiegelprofil zu vergleichmäßigen, um die Schmierung zwischen Strang und Kokille zu verbessern und Strangoberflächenfehler, welche durch ein Einfangen von Gießschlacke entstehen können, zu verringern.It is well known in the art to produce thin slabs in the continuous casting process. In this case, a metallic melt is produced, which is transferred by means of a steel ladle in a distributor. From the distributor, the metallic melt flows via a pouring tube into a mold, which is moved in a cooled and oscillating manner. In the mold, a strand is formed from the metallic melt with a solidified shell and a largely not yet solidified cross-section within the solidified shell. When leaving the mold, the strand is taken up by a transport system with a plurality of strand guide rollers, between which the strand is passed through the so-called pouring arc and is cooled to complete solidification. It is also known to slow the flow rate of the metallic melt inside the already partially solidified strand within the mold by means of an electromagnetic brake (EMBR: Electromagnetic Brake). Here, the goal is to reduce the flow rate of the molten steel at the bath level and to even out the bath level profile in order to improve the lubrication between the strand and the mold and to reduce strand surface defects that may result from catching foundry slag.
Zur Herstellung der Dünnbrammen mit Dicken zwischen 40 bis 120 Millimetern weist die Kokille typischerweise im oberen Teil einen trichterförmig erweiterten Querschnitt auf und im unteren Teil einen rechteckigen Querschnitt. Aufgrund dieser geringen Dicken sind die Durcherstarrungszeiten beim Dünnbrammen-Stranggießen vergleichsweise kurz und der Anteil von flüssiger Schmelze im Inneren des teilerstarrten Stranges gering. Hierdurch ergibt sich zwangsläufig ein grobes, streng gerichtetes, stengelkristallines Gefüge beim Stranggießen von Dünnbrammen. Ein solches Gefüge kann sich jedoch nachteilig auf die Oberflächen- und Innenbeschaffenheit der aus den Dünnbrammen hergestellten Produkte auswirken. Beispielsweise können je nach Stahlsorte und Gießbedingungen an den aus dem Dünnbrammenmaterial gefertigten Produkten Längsstreifigkeiten an der Produktoberfläche, inhomogene mechanische Eigenschaften, Gefügezeiligkeiten, Kernseigerungen, reduzierte HIC-Beständigkeit (Hydrogen Induced Cracking: Wasserstoff induzierte Rissbildung) und Innenrissanfälligkeiten auftreten.For the production of thin slabs with thicknesses between 40 to 120 millimeters, the mold typically has a funnel-shaped enlarged cross section in the upper part and a rectangular cross section in the lower part. Due to these small thicknesses, the solidification times in thin-slab continuous casting are comparatively short and the proportion of liquid melt in the interior of the partially solidified strand is low. This inevitably results in a coarse, strictly directed, columnar structure in the continuous casting of thin slabs. However, such a structure may adversely affect the surface and interior condition of the products made from the thin slabs. For example, depending on the steel grade and casting conditions on the products made of the thin slab material longitudinal striations on the product surface, Inhomogeneous mechanical properties, microstructures, core segregations, reduced HIC resistance (Hydrogen Induced Cracking) and internal cracking susceptibility occur.
Es ist vom konventionellen Dickbrammen-Stranggießen bekannt, Längsstreifigkeiten bei Dynamostählen durch ein Gießen mit sehr niedriger Überhitzung zu vermeiden. Beim Dickbrammen-Stranggießen ist jedoch eine vergleichsweise lange Durcherstarrungszeit gegeben, so dass Überhitzungen der Stahlschmelze im Tundish unterhalb von ca. 12 Kelvin ausreichen, um eine ausreichende Gefügeverfeinerung zu erzielen. Die Gefügeverfeinerung kann als ausreichend bezeichnet werden, wenn die Ausdehnung der globulitischen Kernzone in Dickenrichtung mehr als 30 % beträgt. Um den gleichen Effekt bei Dünnbrammen zu erzielen, müsste aufgrund der kürzeren Durcherstarrungszeiten eine derart niedrige Überhitzung gewählt werden, dass gießtechnische Probleme in Form von Zusetzungen der Tauchrohre in der Kokille (sogenanntes "Clogging") auftreten würden, woraus Strangoberflächenfehler oder sogar Strangdurchbrüche resultieren können.It is known from conventional thick slab continuous casting to avoid longitudinal streaks in dynamo steels by casting with very low overheating. In thick slab continuous casting, however, a comparatively long through-solidification time is given, so that overheating of the molten steel in the tundish below about 12 Kelvin is sufficient to achieve sufficient structural refinement. The microstructure refinement can be said to be sufficient if the expansion of the globulitic core zone in the thickness direction is more than 30%. In order to achieve the same effect in thin slabs, such a low overheating would have to be chosen due to the shorter solidification times that casting problems in the form of clogging of the dip tubes in the mold (so-called "clogging") would occur, resulting in strand surface defects or even strand breakthroughs.
Aus der Fachliteratur (z.B. "
Aus der Druckschrift
Der Einsatz einer elektromagnetischen Bremse und/oder eines elektromagnetischen Rührers beim Stranggießen von Stahl ist für Dickbrammenformate ferner bekannt aus den Druckschriften
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Aus JPH-08 323454 A ist ein Verfahren zum kontinuierlichen Stranggießen von Dünnbrammen bekannt, bei welchem in der Kokille eine Überhitzung von weniger als 0 °C eingestellt werden soll oder bei welchem unterhalb der Kokille die nicht erstarrte Schmelze gerührt werden soll. Während des Abführens des Stranges soll unterhalb der Kokille innerhalb des Biegebereichs des Stranges, in welchem eine Vielzahl an Drückrollen angeordnet ist, die vollständige Durcherstarrung des Stranges verhindert werden, um das Zusammendrücken des nicht vollständig erstarrten Stranges durch die Drückrollen zu ermöglichen. Ziel des Verfahrens ist die Herstellung von Dünnbrammen mit geringer Mittenseigerung.From JPH-08 323454 A a method for continuous continuous casting of thin slabs is known in which in the mold overheating of less than 0 ° C to be set or in which below the mold, the non-solidified melt to be stirred. During the removal of the strand is to be prevented below the mold within the bending region of the strand in which a plurality of spinning rollers, the complete solidification of the strand to allow the compression of the incompletely solidified strand by the spinning rollers. The aim of the process is the production of thin slabs with low center segregation.
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Beim Dünnbrammenstranggießen besteht die besondere Schwierigkeit darin, bei den im Vergleich zum Dickbrammenstranggießen kurzen Durcherstarrungszeiten und dem kleinvolumigen Flüssiganteil im Stranginneren eine signifikante Gefügeverfeinerung zu erreichen. Die vorliegende Erfindung löst dieses Problem.In thin slab continuous casting, the particular difficulty is to achieve a significant microstructural refinement in the case of the through-solidification times which are short compared to thick-slab continuous casting and the small-volume liquid fraction in the strand interior. The present invention solves this problem.
Es ist eine Aufgabe der vorliegenden Erfindung, ein Verfahren und eine Vorrichtung zur Herstellung von Dünnbrammen im Stranggussverfahren bereitzustellen, welche trotz kurzer Durcherstarrungszeiten und vergleichsweise kleinvolumiger Flüssiganteile im Stranginneren die Erzeugung einer großen Kernzone mit feinkörnigem, globulitischem Gefüge im Dünnbrammenstrang ermöglichen, um die beim Stand der Technik durch ein grobes, streng gerichtetes, stengelkristallines Gefüge im Dünnbrammenstrang hervorgerufenen Nachteile zu verhindern. Ferner soll die Gefahr von Tauchrohrzusetzungen durch eine zu niedrige Überhitzung vermieden werden. Gelöst wird diese Aufgabe mit einem Verfahren zum Dünnbrammen-Stranggießen nach Anspruch 1, aufweisend die Verfahrensschritte: Zuführen einer metallischen Schmelze in eine Kokille, Formen eines teilerstarrten Dünnbrammenstrangs aus der metallischen Schmelze in der Kokille, Reduzieren der Strömungsgeschwindigkeit der metallischen Schmelze im teilerstarrten Dünnbrammenstrang mittels einer im Bereich der Kokille angeordneten elektromagnetischen Bremse (EMBR) und Abführen des teilerstarrten Dünnbrammenstrangs aus der Kokille mittels eines Strangführungssystems, wobei nichterstarrte Teile des teilerstarrten Dünnbrammenstrangs mittels eines entlang der Strangabzugsrichtung des Dünnbrammenstrangs stromabwärts unterhalb der Kokille angeordneten elektromagnetischen Rührers gerührt werden, wobei mittels des elektromagnetischen Rührers ein elektromagnetisches Wanderfeld in einem entlang der Strangabzugsrichtung zwischen 20 und 7.000 Millimeter von der Kokille entfernten Bereich des Dünnbrammenstrangs erzeugt wird.It is an object of the present invention to provide a method and apparatus for the production of thin slabs in the continuous casting process, which despite short Durcherstarrungszeiten and relatively small-volume liquid portions in the strand interior to produce a large core zone with fine-grained, globulitischem microstructure in the thin slab strand to the in the state of Technique by a coarse, strictly directed, columnar structure in the thin slab strand to prevent disadvantages. Furthermore, the risk of Tauchrohrzusetzungen should be avoided by too low overheating. This object is achieved with a method for thin slab continuous casting according to
Die erfindungsgemäße Vorrichtung hat gegenüber dem Stand der Technik den Vorteil, dass durch eine spezifisch für das Dünnbrammenstranggießen ausgelegte Konzeption zum elektromagnetischen Rühren eine Verfeinerung des Erstarrungsgefüges im Inneren des Dünnbrammenstrangs erzielt wird und durch den gleichzeitigen Einsatz einer elektromagnetischen Bremse verhindert wird, dass die vom Rührer induzierte Erhöhung der Strömungsgeschwindigkeit der Stahlschmelze im Kokillenbereich zu unzulässig starken lokalen Badspiegelschwankungen, d.h. zu Badspiegelschwankungen von beispielsweise mehr als 15 mm, führt. Hohe Turbulenzen am Badspiegel können zu Strangdurchbrüchen oder zu Strangoberflächenfehlern durch am Badspiegel der Kokille eingefangene Gießschlacke führen. Sowohl Strangdurchbrüche als auch Strangoberflächenfehler sollen vermieden werden. Es hat sich überraschenderweise gezeigt, dass durch das elektromagnetische Rühren im Abstand von 20 bis 7.000 Millimetern unterhalb der Kokille und insbesondere von der Kokillenunterseite ein beschleunigter und gleichmäßiger Überhitzungsabbau bewirkt wird, welcher vorteilhafterweise zur Bildung einer ausreichend großen, d.h. insbesondere mindestens 30 % in Dickenrichtung betragenden, Kernzone mit feinkörnigem, globulitischem Gefüge im Inneren des Dünnbrammenstrangs führt, während grobe, stengelkristalline Strukturen durch das Rühren limitiert werden. Trotz der beim Stranggießen von Dünnbrammen typischen kurzen Durcherstarrungszeiten und kleinvolumigen Flüssiganteile im Inneren des Dünnbrammenstrangs bildet sich diese feinkörnige, globulitische Kernzone im Erstarrungsgefüge aus, wodurch die Entstehung von Stengelkristallen zwischen der Randzone und dem Zentrumsbereich des Strangs stark reduziert wird. Die Ausdehnung der globulitischen Kernzone in Dickenrichtung beträgt dann insbesondere mindestens 30 %. Beim hergestellten Produkt können somit Längsstreifigkeiten, Gefügezeiligkeiten, Kernseigerungen und Innenrissanfälligkeiten verringert und die HIC-Beständigkeit und die Homogenität der mechanischen und magnetischen Eigenschaften gesteigert werden. Vorteilhafter Weise kann ferner an einer höheren und unkritischen Überhitzung festgehalten werden, so dass die Gefahr von Gießstörungen in Form von Tauchrohrzusetzungen und daraus resultierenden Strangoberflächenfehlern oder Strangdurchbrüchen ausgeräumt wird. Denkbar ist, dass beim vorliegenden Verfahren beispielsweise eine Überhitzung der Stahlschmelze im Tundish zwischen 10 und 50 Kelvin, vorzugsweise um 20 Kelvin, angewandt wird. Mittels des elektromagnetischen Rührers wird ein elektromagnetisches Wanderfeld in einem entlang der Strangabzugsrichtung zwischen 20 und 7.000 Millimeter von der Kokille entfernten Bereich des Dünnbrammenstrangs erzeugt. Unter einem zwischen 20 und 7.000 Millimeter von der Kokille entfernten Bereich des Dünnbrammenstrangs ist im Sinne der vorliegenden Erfindung insbesondere derjenige Bereich des Dünnbrammenstrangs zu verstehen, der von der Kokillenunterseite einen Abstand zwischen 20 und 7.000 Millimeter aufweist. Alternativ könnte die Position des elektromagnetischen Rührers und des elektromagnetischen Wanderfeldes relativ zur Kokille auch über den Abstand zum Badspiegel in der Kokille definiert werden, welcher typischerweise um die 100 Millimeter unterhalb der Kokillenoberseite liegt. Vorzugsweise ist der elektromagnetische Rührer derart angeordnet, dass das Wanderfeld unmittelbar unterhalb der Kokille auf die noch nicht erstarrten Teile des Strangs einwirkt, da eine positive Beeinflussung des Korngefüges bei bereits erstarrten Teilen des Strangs durch das Wanderfeld nicht mehr möglich ist. Bevorzugt wird das elektromagnetische Wanderfeld in einem entlang der Strangabzugsrichtung zwischen 50 und 3.000 Millimeter von der Kokille bzw. von der Kokillenunterseite entfernten Bereich erzeugt. Denkbar ist auch, die Position des elektromagnetischen Rührers bzw. des elektromagnetischen Wechselfeldes entlang der Strangabzugsrichtung über den Abstand zum Badspiegel in der Kokille zu definieren: Der Abstand zum Badspiegel entlang der Strangabzugsrichtung umfasst vorzugsweise zwischen 0,9 und 3,8 Meter und vorzugsweise zwischen 1,5 und 2,5 Meter. Im Sinne der vorliegenden Erfindung ist insbesondere entweder ein einziger elektromagnetischer Rührer auf einer Seite des Dünnbrammenstrangs, entweder auf der Festseite oder der Losseite, angeordnet oder es ist auf jeder Seite, d.h. sowohl auf der Festseite, als auch auf der Losseite ein separater elektromagnetischer Rührer angeordnet. Als Festseite wird dabei insbesondere diejenige Breitseite der Strangführungssegmente bezeichnet, die in ihrer Position stets unverändert bleibt und als sogenannte Bezugslinie dient. Anpassungen der Strangdickenformate werden dann stets über die gegenüberliegende Losseite vorgenommen. Das erfindungsgemäße Verfahren wird insbesondere zur Herstellung von Dünnbrammen im Stranggießverfahren und daraus gefertigtem Warmband oder Kaltband verwendet. Das Warmband oder Kaltband wird insbesondere zur Herstellung von Elektroblechen (nichtkornorientiert oder kornorientiert) oder Blechen höherfester Stähle mit Streckgrenzenwerten größer als 400 Megapascal (bspw. Vergütungsstahl) verwendet. Eine Dünnbramme im Sinne der vorliegenden Erfindung umfasst insbesondere eine Bramme mit einer Dicke zwischen 40 bis 120 Millimeter. Zur präzisen Beschreibung der geometrischen Verhältnisse werden im Folgenden neben der Strangabzugsrichtung noch zwei Querrichtungen, eine erste Querrichtung und eine zweite Querrichtung, erwähnt. Die erste Querrichtung verläuft dabei stets senkrecht zur Strangabzugsrichtung und parallel zur Strangoberflächennormalen der Brammenbreitseite, während die zweite Querrichtung stets senkrecht zur Strangabzugsrichtung und parallel zur Strangoberfläche auf der Brammenbreitseite verläuft. Unter der Brammenbreitseite ist dabei diejenige Seite des rechteckförmigen Querschnitts des Dünnbrammenstrangs zu verstehen, welche die größere Ausdehnung aufweist. Die erste und die zweite Querrichtung verlaufen somit beide senkrecht zur Strangabzugsrichtung, sowie senkrecht zueinander.The device according to the invention has the advantage over the prior art that a design for electromagnetic stirring designed for thin-slab casting achieves a refinement of the solidification structure in the interior of the thin slab strand and the simultaneous use of an electromagnetic brake prevents the flow induced by the agitator Increasing the flow velocity of the molten steel in the mold area to impermissibly strong local Badspiegelschwankungen, ie to Badspiegelschwankungen of, for example, more than 15 mm leads. High turbulence at the bath level can lead to strand breakthroughs or strand surface defects due to casting slag trapped at the bath level of the mold. Both strand breaks and strand surface defects should be avoided. It has surprisingly been found that an accelerated and uniform overheating degradation is effected by the electromagnetic stirring at a distance of 20 to 7,000 millimeters below the mold and in particular from the mold bottom, which advantageously amount to the formation of a sufficiently large, ie in particular at least 30% in the thickness direction , Core zone with fine-grained, globulitischem structure inside the thin slab strand leads, while coarse, columnar crystalline structures are limited by the stirring. Despite the short through solidification times and small volume liquid contents inside the thin slab strand typical of continuous casting of thin slabs, this fine-grained, globulitic core zone forms in the solidification structure, whereby the formation of stem crystals between the edge zone and the center region of the strand is greatly reduced. The expansion of the globulitic core zone in the thickness direction is then in particular at least 30%. In the case of the product thus produced, longitudinal streaks, microstructures, core segregations and internal cracking susceptibilities may occur reduced and the HIC resistance and the homogeneity of the mechanical and magnetic properties are increased. Advantageously, it is also possible to retain a higher and uncritical overheating, so that the risk of casting defects in the form of immersion tube additions and resulting strand surface defects or strand breakthroughs is eliminated. It is conceivable that in the present process, for example, an overheating of the molten steel in tundish between 10 and 50 Kelvin, preferably applied by 20 Kelvin. By means of the electromagnetic stirrer, an electromagnetic traveling field is generated in a region of the thin slab strand which is removed from the mold along the strand withdrawal direction between 20 and 7,000 millimeters. For the purposes of the present invention, a region of the thin slab strand which is between 20 and 7,000 millimeters from the mold is to be understood in particular as that region of the thin slab strand which has a distance of between 20 and 7,000 millimeters from the base of the mold. Alternatively, the position of the electromagnetic stirrer and the electromagnetic traveling field relative to the mold could also over the distance to the bath level in the mold be defined, which is typically located about 100 millimeters below the mold top. Preferably, the electromagnetic stirrer is arranged such that the traveling field acts immediately below the mold on the not yet solidified parts of the strand, since a positive effect on the grain structure in already solidified parts of the strand by the traveling field is no longer possible. Preferably, the electromagnetic traveling field is generated in a region along the strand withdrawal direction between 50 and 3,000 millimeters away from the mold or from the bottom of the mold. It is also conceivable to define the position of the electromagnetic stirrer or of the electromagnetic alternating field along the strand withdrawal direction over the distance to the bath level in the mold: The distance to the bath level along the strand withdrawal direction preferably comprises between 0.9 and 3.8 meters and preferably between 1 , 5 and 2.5 meters. For the purposes of the present invention, in particular either a single electromagnetic stirrer is arranged on one side of the thin slab strand, either on the fixed side or the loose side, or a separate electromagnetic stirrer is arranged on each side, ie both on the fixed side and on the loose side , In particular, that broad side of the strand guide segments is referred to as the fixed side, which always remains unchanged in its position and serves as a so-called reference line. Adjustments to the strand thickness formats are then always made on the opposite lot side. The process according to the invention is used in particular for the production of thin slabs in the continuous casting process and hot strip or cold strip produced therefrom. The hot strip or cold strip is used in particular for the production of electrical sheets (non-grain oriented or grain oriented) or sheets of higher strength steels with yield strength values greater than 400 megapascals (eg tempered steel). A thin slab in the sense of the present invention comprises in particular a slab with a thickness of between 40 and 120 millimeters. For a precise description of the geometric relationships, two transverse directions, a first transverse direction and a second transverse direction, are mentioned below next to the strand withdrawal direction. The first transverse direction is always perpendicular to the strand withdrawal direction and parallel to the strand surface normal of the slab broadside, while the second transverse direction is always perpendicular to the strand withdrawal direction and parallel to the strand surface on the slab broadside. Under the broad slab side is that side of the rectangular cross-section of the thin slab strand to understand, which has the greater extent. The first and the second transverse direction thus both run perpendicular to the strand withdrawal direction, and perpendicular to each other.
Vorteilhafte Ausgestaltungen und Weiterbildungen der Erfindung sind den Unteransprüchen sowie der Beschreibung unter Bezugnahme auf die Zeichnungen entnehmbar.Advantageous embodiments and modifications of the invention are the dependent claims and the description with reference to the drawings.
Gemäß einer bevorzugten Ausführungsform der vorliegenden Erfindung ist vorgesehen, dass die nichterstarrten Teile innerhalb der Kokille und/oder während des Abführens des teilerstarrten Dünnbrammenstrangs aus der Kokille durch das Strangführungssystems mittels des elektromagnetischen Rührers, welcher unterhalb der Kokille positioniert ist, gerührt werden. In vorteilhafter Weise wird hierdurch sichergestellt, dass beim Rühren der Anteil noch nicht erstarrter metallischer Schmelze im Inneren des Dünnbrammenstrangs noch ausreichend groß ist, d.h. mindestens 50 % der Strangdicke beträgt, um eine im Querschnitt möglichst großflächige Kernzone mit feinkörnigem, globulitischem Gefüge zu erhalten, d. h. um eine globulitische Kernzone mit einer Ausdehnung in Dickenrichtung von der Bramme von mindestens 30 % zu erhalten.According to a preferred embodiment of the present invention, it is provided that the non-solidified parts within the mold and / or during the discharge of the partially solidified thin slab strand from the mold through the strand guide system by means of the electromagnetic stirrer, which is positioned below the mold, are stirred. In an advantageous manner, this ensures that during stirring the proportion of not yet solidified molten metal inside the thin slab strand is still sufficiently large, i. at least 50% of the strand thickness is to obtain a cross-section as large as possible core zone with fine-grained, globulitic structure, d. H. to obtain a globulitic core zone having a thicknesswise extension of the slab of at least 30%.
Gemäß einer weiteren bevorzugten Ausführungsform der vorliegenden Erfindung ist vorgesehen, dass der elektromagnetische Rührer derart eingestellt wird, dass das elektromagnetische Wanderfeld entlang einer zweiten Querrichtung, die senkrecht zur Strangabzugsrichtung und parallel zu einer Strangoberfläche auf einer Breitseite des Dünnbrammenstrangs verläuft, von einem ersten Randbereich des Dünnbrammenstrangs zu einem dem ersten Randbereich gegenüberliegendem zweiten Randbereich des Dünnbrammenstrangs läuft. Auf diese Weise wird ein Umrühren der noch nicht erstarrten metallischen Schmelze im Dünnbrammenstrang erzielt, so dass sich beim Erstarren feine, globulitische Körner im Erstarrungsgefüge bilden. Vorzugsweise wird das elektromagnetische Wanderfeld nach Ablauf einer Zeitspanne von 1 bis 60 Sekunden, besonders bevorzugt zwischen 1 und 10 Sekunden, umgekehrt, so dass das elektromagnetische Wanderfeld anschließend entlang der zweiten Querrichtung von einem zweiten Randbereich des Dünnbrammenstrangs zum ersten Randbereich des Dünnbrammenstrangs läuft. Nach einem erneuten Ablauf der Zeitspanne von 1 bis 60 Sekunden, vorzugsweise wiederum 1 bis 10 Sekunden, wird das elektromagnetische Wanderfeld erneut umgekehrt und der Zyklus beginnt von vorn.According to another preferred embodiment of the present invention, it is provided that the electromagnetic stirrer is adjusted such that the electromagnetic traveling field along a second transverse direction, which is perpendicular to the strand withdrawal direction and parallel to a strand surface on a broad side of the thin slab strand, from a first edge region of the thin slab strand to a first edge region opposite the second edge region of the thin slab strand runs. In this way, a stirring of the not yet solidified metallic melt in the thin slab strand is achieved, so that form on solidification, fine, globulitic grains in the solidification structure. The electromagnetic traveling field is preferably reversed after a time span of 1 to 60 seconds, particularly preferably between 1 and 10 seconds, so that the electromagnetic traveling field subsequently runs along the second transverse direction from a second edge region of the thin slab strand to the first edge region of the thin slab strand. After a lapse of the period of 1 to 60 seconds, preferably again 1 to 10 seconds, the traveling electromagnetic field is reversed again and the cycle begins again.
Gemäß einer alternativen bevorzugten Ausführungsform der vorliegenden Erfindung ist vorgesehen, dass mittels des elektromagnetischen Rührers ein bidirektionales, symmetrisches elektromagnetisches Wanderfeld über die Breite des Dünnbrammenstrangs erzeugt wird, wobei der elektromagnetische Rührer derart eingestellt wird, dass ein erstes Subfeld des elektromagnetischen Wanderfelds vom Zentrum des Dünnbrammenstrangs zu einem ersten Randbereich des Dünnbrammenstrangs läuft und dass ein zweites Subfeld des elektromagnetischen Wanderfelds vom Zentrum zu einem dem ersten Randbereich gegenüberliegenden zweiten Randbereich des Dünnbrammenstrangs läuft. Bevorzugt wird dieses elektromagnetische Wanderfeld 1 bis 60 Sekunden, besonders bevorzugt zwischen 1 und 10 Sekunden, gehalten. Danach werden das durch den elektromagnetischen Rührer erzeugte elektromagnetische Wanderfeld und damit die Richtung der beiden Subfelder umgekehrt. Dieses umgekehrte elektromagnetische Wanderfeld wird ebenfalls bevorzugt zwischen 1 bis 60 Sekunden und besonders bevorzugt zwischen 1 und 10 Sekunden, gehalten. Danach wird das elektromagnetische Wanderfeld erneut umgekehrt und der Zyklus beginnt von vorn. Diese bevorzugte Ausführungsform sorgt für ein symmetrisches Umrühren der noch nicht erstarrten metallischen Schmelze innerhalb der bereits erstarrten Randzone des Dünnbrammenstrangs, so dass ein symmetrisches Erstarrungsgefüge mit feinen, globulitischen Körnern entsteht.According to an alternative preferred embodiment of the present invention, it is provided that a bidirectional, symmetrical traveling electromagnetic field across the width of the thin slab strand is generated by means of the electromagnetic stirrer, wherein the electromagnetic stirrer is adjusted so that a first subfield of the electromagnetic traveling field from the center of the thin slab strand to a first edge region of the thin slab strand runs and that a second subfield of the electromagnetic traveling field from the center to a second edge region of the thin slab strand opposite the first edge region runs. It is preferred this electromagnetic traveling
Gemäß einer weiteren alternativen bevorzugten Ausführungsform der vorliegenden Erfindung ist vorgesehen, dass mittels des elektromagnetischen Rührers ein bidirektionales, symmetrisches elektromagnetisches Wanderfeld über die Breite des Dünnbrammenstrangs erzeugt wird, wobei der elektromagnetische Rührer derart eingestellt wird, dass ein erstes Subfeld des elektromagnetischen Wanderfelds von einem ersten Randbereich des Dünnbrammenstrangs zum Zentrum des Dünnbrammenstrangs läuft und dass ein zweites Subfeld des elektromagnetischen Wanderfelds von einem dem ersten Randbereich gegenüberliegenden zweiten Randbereich des Dünnbrammenstrangs zum Zentrum des Dünnbrammenstrangs läuft. Vorzugsweise wird dieses elektromagnetische Wanderfeld 1 bis 60 Sekunden, insbesondere zwischen 1 und 10 Sekunden, gehalten. Danach werden das durch den elektromagnetischen Rührer erzeugte elektromagnetische Wanderfeld und damit die Richtung der beiden Subfelder umgekehrt. Dieses umgekehrte elektromagnetische Wanderfeld wird ebenfalls zwischen 1 bis 60 Sekunden, insbesondere zwischen 1 und 10 Sekunden, gehalten. Danach wird das elektromagnetische Wanderfeld erneut umgekehrt und der Zyklus beginnt von vorn. Diese bevorzugte Ausführungsform sorgt ebenfalls für ein symmetrisches Umrühren der noch nicht erstarrten metallischen Schmelze innerhalb der bereits erstarrten Randzone des Dünnbrammenstrangs, so dass ein symmetrisches Erstarrungsgefüge mit feinen, globulitischen Körner entsteht.According to a further alternative preferred embodiment of the present invention, it is provided that a bidirectional, symmetrical traveling electromagnetic field is generated across the width of the thin slab strand by means of the electromagnetic stirrer, wherein the electromagnetic stirrer is adjusted such that a first subfield of the electromagnetic traveling field from a first edge region of the thin slab strand runs to the center of the thin slab strand and that a second sub-field of the electromagnetic traveling field from a first edge region opposite the second edge region of the thin slab strand runs to the center of the thin slab strand. Preferably, this electromagnetic traveling field is held for 1 to 60 seconds, in particular between 1 and 10 seconds. Thereafter, the electromagnetic traveling field generated by the electromagnetic stirrer and thus the direction of the two subfields are reversed. This reverse electromagnetic traveling field is also held between 1 to 60 seconds, in particular between 1 and 10 seconds. Thereafter, the traveling electromagnetic field is reversed again and the cycle starts again. This preferred embodiment also ensures a symmetrical stirring of the not yet solidified metallic melt within the already solidified edge zone of the thin slab strand, so that a symmetrical solidification structure with fine, globulitic grains is formed.
Gemäß einer weiteren bevorzugten Ausführungsform der vorliegenden Erfindung ist vorgesehen, dass mittels des elektromagnetischen Rührers ein elektromagnetisches Wanderfeld über die Breite des Dünnbrammenstrangs erzeugt wird, dessen magnetische Flussdichte im Mittel bevorzugt 0,1 bis 0,6 Tesla, besonders bevorzugt 0,3 bis 0,5 Tesla und ganz besonders bevorzugt im Wesentlichen 0,4 Tesla beträgt. Es hat sich gezeigt, dass ein Wechselfeld mit Amplituden im Bereich von bevorzugt 0,1 bis 0,6 Tesla, besonders bevorzugt 0,3 bis 0,5 Tesla und ganz besonders bevorzugt im Wesentlichen 0,4 Tesla ausreicht, um einen beschleunigten und gleichmäßigen Überhitzungsabbau in der metallischen Schmelze zu erreichen. Dieser Effekt wird vorteilhafterweise durch einen derart eingestellten elektromagnetischen Rührer erzielt, dass die Strömungsgeschwindigkeit der nicht erstarrten Teile im teilerstarrten Dünnbrammenstrang maximal 0,7 Meter pro Sekunde oder mindestens 0,2 Meter pro Sekunde beträgt und bevorzugt zwischen 0,2 und 0,7 Meter pro Sekunde liegt. Die hiermit verbundene Umwälzung der nichterstarrten Teile im Dünnbrammenstrang sorgt für den beschleunigten und gleichmäßigen Abbau der Überhitzung und dadurch für die gewünschte Gefügeverfeinerung, ohne dass eine von vorneherein niedrigere Überhitzung gewählt werden muss, durch welche die Gefahr von Tauchrohrzusetzungen drastisch zunehmen würde.According to a further preferred embodiment of the present invention, it is provided that by means of the electromagnetic stirrer an electromagnetic traveling field is generated across the width of the thin slab strand whose magnetic flux density averages preferably 0.1 to 0.6 Tesla, particularly preferably 0.3 to 0, 5 Tesla and most preferably substantially 0.4 Tesla. It has been found that an alternating field with amplitudes in the range of preferably 0.1 to 0.6 Tesla, more preferably 0.3 to 0.5 Tesla and most preferably substantially 0.4 Tesla sufficient to achieve an accelerated and uniform overheating degradation in the metallic melt. This effect is advantageously achieved by an electromagnetic stirrer set in such a way that the flow rate of the non-solidified parts in the partially solidified thin slab strand is at most 0.7 meters per second or at least 0.2 meters per second, and preferably between 0.2 and 0.7 meters per second Second lies. The associated circulation of the non-solidified parts in the thin slab strand ensures the accelerated and uniform reduction of overheating and thus for the desired microstructural refinement, without having to choose a lower overheating from the outset, through which the risk of immersion tube additions would increase dramatically.
Gemäß einer weiteren bevorzugten Ausführungsform der vorliegenden Erfindung ist vorgesehen, dass der elektromagnetische Rührer derart eingestellt wird, dass die Rührfrequenz mindestens 0,1 Hz oder maximal 10 Hertz beträgt und bevorzugt zwischen 1 und 10 Hz liegt. Es hat sich gezeigt, dass dieser Rührfrequenzbereich besonders vorteilhaft ist. Bei einer Rührfrequenz kleiner als 0,1 Hz liegt kein elektromagnetisches Wanderfeld vor, so dass keine Rührwirkung auftritt. Wenn die Rührfrequenz größer als 10 Hz ist, dann ist die Eindringtiefe des elektromagnetischen Wanderfelds in das Stranginnere zu gering und es wird keine Gefügeverfeinerung erzielt.According to a further preferred embodiment of the present invention, it is provided that the electromagnetic stirrer is adjusted such that the stirring frequency is at least 0.1 Hz or at most 10 Hertz, and preferably between 1 and 10 Hz. It has been shown that this stirring frequency range is particularly advantageous. At a stirring frequency less than 0.1 Hz is no electromagnetic traveling field, so that no stirring effect occurs. If the stirring frequency is greater than 10 Hz, then the penetration depth of the electromagnetic traveling field in the strand interior is too low and no structural refinement is achieved.
Gemäß einer weiteren bevorzugten Ausführungsform der vorliegenden Erfindung ist vorgesehen, dass mittels der elektromagnetischen Bremse ein elektromagnetisches Feld innerhalb der Kokille erzeugt wird, dessen magnetische Flussdichte bevorzugt 0,1 bis 0,3 Tesla, besonders bevorzugt 0,15 bis 0,25 Tesla und ganz besonders bevorzugt im Wesentlichen 0,2 Tesla beträgt. Vorteilhafterweise wird hierdurch die Strömungsgeschwindigkeit der metallischen Schmelze zwischen den teilerstarrten Randbereichen des Strangs gebremst und somit Gießspiegelschwankungen, sowie aus Gießspiegelschwankungen resultierende Oberflächenfehler (sogenannte Schalenfehler) und Innenfehler (bspw. Gießschlackeneinschlüsse) verhindert.According to a further preferred embodiment of the present invention, it is provided that by means of the electromagnetic brake, an electromagnetic field is generated within the mold whose magnetic flux density preferably 0.1 to 0.3 Tesla, more preferably 0.15 to 0.25 Tesla and all more preferably substantially 0.2 tesla. Advantageously, the flow velocity of the metallic melt between the partially solidified edge regions of the strand is thereby braked, thus preventing pouring mirror fluctuations, as well as surface defects resulting from pouring mirror fluctuations (so-called shell defects) and internal defects (for example, slag inclusions).
Gemäß einer weiteren bevorzugten Ausführungsform der vorliegenden Erfindung ist vorgesehen, dass die Magnetfeldstärken des durch den elektromagnetischen Rührer hervorgerufenen elektromagnetischen Wanderfeldes und des durch die elektromagnetische Bremse hervorgerufenen Feldes aufeinander abgestimmt werden. Es hat sich gezeigt, dass eine Abstimmung der Magnetfeldstärken des durch den elektromagnetischen Rührer hervorgerufenen elektromagnetischen Wanderfeldes und des durch die elektromagnetische Bremse hervorgerufenen Feldes vorteilhaft ist. Die Abstimmung erfolgt vorzugsweise, indem die Magnetfeldstärke des Feldes der elektromagnetischen Bremse bei Zuschalten des elektromagnetischen Rührers um 20 bis 80 % ihres Grundwerts auf Werte zwischen 0,1 bis 0,3 Tesla angehoben wird. Als Grundwert wird in diesem Zusammenhang die Magnetfeldstärke des Feldes der elektromagnetischen Bremse verstanden, wie sie ohne zusätzlichen Einsatz eines elektromagnetischen Rührers typischerweise eingesetzt wird. Typische Grundeinstellungen für eine elektromagnetische Bremse ohne Einsatz eines elektromagnetischen Rührers sind Felder mit Magnetfeldstärken zwischen 0,08 und 0,2 Tesla.According to a further preferred embodiment of the present invention it is provided that the magnetic field strengths of the electromagnetic traveling field caused by the electromagnetic stirrer and of the field caused by the electromagnetic brake are matched to one another. It has been found that a tuning of the magnetic field strengths of the traveling electromagnetic field caused by the electromagnetic stirrer and the field caused by the electromagnetic brake is advantageous. The vote is preferably carried out by When the electromagnetic stirrer is energized, the magnetic field strength of the electromagnetic brake field is increased by 20 to 80% of its basic value to values between 0.1 and 0.3 Tesla. The basic value in this context is the magnetic field strength of the field of the electromagnetic brake, as is typically used without the additional use of an electromagnetic stirrer. Typical basic settings for an electromagnetic brake without the use of an electromagnetic stirrer are fields with magnetic field strengths between 0.08 and 0.2 Tesla.
Ein weiterer Gegenstand der vorliegenden Erfindung zur Lösung der eingangs genannten Aufgabe ist eine Vorrichtung zum Dünnbrammenstranggießen, insbesondere unter Verwendung des erfindungsgemäßen Verfahrens, welches ein Zuführmittel zum Zuführen einer metallischen Schmelze, eine Kokille zum Formen eines teilerstarrten Dünnbrammenstrangs aus der metallischen Schmelze, eine im Bereich der Kokille angeordnete elektromagnetische Bremse zum Reduzieren der Strömungsgeschwindigkeit der metallischen Schmelze im Inneren des teilerstarrten Stranges innerhalb der Kokille und ein Strangführungssystem zum Abführen des teilerstarrten Dünnbrammenstrangs aus der Kokille aufweist, wobei die Vorrichtung ferner einen entlang der Strangabzugsrichtung des Dünnbrammenstrangs stromabwärts unterhalb der Kokille angeordneten elektromagnetischen Rührer zum Rühren von nichterstarrten Teilen des teilerstarrten Dünnbrammenstrangs aufweist, wobei der elektromagnetische Rührer entlang der Strangabzugsrichtung zwischen 20 und 7.000 Millimeter von der Kokille beabstandet ist.Another object of the present invention to achieve the object mentioned is a device for thin slab continuous casting, in particular using the method according to the invention, which comprises a supply means for supplying a metallic melt, a mold for forming a partially solidified thin slab strand from the metallic melt, one in the An electromagnetic brake for reducing the flow rate of the metallic melt inside the teilerstarrten strand within the mold and a strand guide system for discharging the partially solidified thin slab strand from the mold, wherein the device further comprises a along the strand withdrawal direction of the thin slab downstream downstream of the mold arranged electromagnetic stirrer for Stirring of non-solidified parts of the partially solidified thin slab strand, wherein the electromagnetic stirrer along the strand Abzu gsrichtung between 20 and 7,000 millimeters from the mold is spaced.
Die erfindungsgemäße Vorrichtung hat gegenüber dem Stand der Technik den Vorteil, dass die metallische Schmelze durch den elektromagnetischen Rührer während des Stranggießens gerührt wird, wodurch eine Verfeinerung des Erstarrungsgefüges im Inneren des Dünnbrammenstrangs erzielt wird. Das Rühren der metallischen Schmelze sorgt für einen beschleunigten und gleichmäßigen Überhitzungsabbau, welcher vorteilhafterweise zur Bildung einer Kernzone mit feinkörnigem, globulitischem Gefüge im Inneren des Dünnbrammenstrangs führt, während grobe stengelkristalline Strukturen durch das Rühren aufgebrochen werden. Trotz der beim Stranggießen von Dünnbrammen typischen kurzen Durcherstarrungszeiten und kleinvolumigen Flüssiganteile im Inneren des Dünnbrammenstrangs bildet sich diese feinkörnige, globulitische Kernzone im Erstarrungsgefüge aus, wodurch die Entstehung von Stengelkristallen zwischen der Randzone und dem Zentrumsbereich des Strangs vermieden oder zumindest unterdrückt wird. Die aus den Dünnbrammen hergestellten Produkte weisen somit deutlich verringerte Längsstreifigkeiten, Gefügezeiligkeiten und Innenrissanfälligkeiten, sowie erhöhte HIC-Beständigkeit und Homogenität der mechanischen und magnetischen Eigenschaften auf. Der elektromagnetische Rührer erzeugt insbesondere ein räumlich und/oder zeitlich veränderliches Magnetfeld im Bereich des Dünnbrammenstrangs. Der elektromagnetische Rührer umfasst vorzugsweise einen Linearfeldrührer, welcher an einer der beiden Breitseiten des Dünnbrammenstrangs angeordnet ist. Denkbar wäre aber auch, dass an beiden gegenüberliegenden Breitseiten des Dünnbrammenstrangs je ein Linearfeldrührer angeordnet ist. Alternativ umfasst der elektromagnetische Rührer einen Drehfeldrührer oder einen Helicoidalrührer.The device according to the invention has the advantage over the prior art that the metallic melt is stirred by the electromagnetic stirrer during the continuous casting, whereby a refinement of the solidification microstructure in the interior of the thin slab strand is achieved. The stirring of the metallic melt provides for an accelerated and uniform overheating degradation, which advantageously results in the formation of a core zone with a fine-grained, globulitic structure inside the thin slab strand, while coarse columnar crystalline structures are broken up by the agitation. Despite the short through solidification times and small volume liquid components inside the thin slab strand typical of continuous casting of thin slabs, this fine-grained, globulitic core zone forms in the solidification structure, whereby the formation of stem crystals between the edge zone and the center region of the strand is avoided or at least suppressed. The products produced from the thin slabs thus have significantly reduced longitudinal streaks, microstructures and susceptibility to internal cracks, as well as increased HIC resistance and homogeneity of the mechanical and magnetic properties. The electromagnetic stirrer in particular generates a spatially and / or temporally variable magnetic field in the region of the thin slab strand. The electromagnetic stirrer preferably comprises a linear-field stirrer, which is arranged on one of the two broad sides of the thin-slab strand. It would also be conceivable, however, that a respective linear field stirrer is arranged on both opposite broad sides of the thin slab strand. Alternatively, the electromagnetic stirrer comprises a rotary field stirrer or a helicoidal stirrer.
Der elektromagnetische Rührer ist entlang der Strangabzugsrichtung des Dünnbrammenstrangs unterhalb der elektromagnetischen Bremse angeordnet. In vorteilhafter Weise wird somit in den noch nicht erstarrten Teilen des Dünnbrammenstrangs ein rascher und gleichmäßiger Abbau der Überhitzung erreicht, bevor die Erstarrung ins Innere des Dünnbrammenstrangs voranschreitet, so dass die Verfeinerung des Erstarrungsgefüges erzielt wird. Grundsätzlich ist der Anteil der globulitischen Kernzone in der Dünnbramme größer, je näher der elektromagnetische Rührer am Meniskus des Dünnbrammenstrangs bzw. am Badspiegel angeordnet ist. Gleichzeitig muss jedoch sichergestellt sein, dass der elektromagnetische Rührer auch im unteren Bereich der Kokille wirksam ist, damit ein frühzeitiger und rascher Abbau der Überhitzung im Stranginneren erzielt wird, und die von dem elektromagnetischen Rührer erzeugten Strömungen in der metallischen Schmelze nicht zu verstärkten Badspiegelschwankungen und nicht zu vergrößerten lokalen Badspiegelüberhöhungen in der Kokille führen. Es hat sich gezeigt, dass der elektromagnetische Rührer hierfür vorteilhafterweise entlang der Strangabzugsrichtung 20 bis 7.000 Millimeter und vorzugsweise 50 bis 3.000 Millimeter von der Kokille und insbesondere von der Kokillenunterseite beabstandet angeordnet sein sollte. Anders ausgedrückt: Der Abstand zwischen dem elektromagnetischen Rührer und dem Badspiegel umfasst vorzugsweise zwischen 0,9 und 3,8 Meter und vorzugsweise zwischen 1,5 und 2,5 Meter. Ferner ist insbesondere vorgesehen, dass der elektromagnetische Rührer 20 bis 1000 Millimeter, vorzugsweise 20 bis 200 Millimeter und besonders bevorzugt 20 bis 40 Millimeter von einer Oberfläche des Dünnbrammenstrangs entlang der ersten Querrichtung beabstandet ist.The electromagnetic stirrer is disposed along the strand take-off direction of the thin slab strand below the electromagnetic brake. Advantageously, a rapid and uniform reduction of overheating is thus achieved in the not yet solidified parts of the thin slab before the solidification progresses into the interior of the thin slab strand, so that the refinement of the solidification microstructure is achieved. In principle, the proportion of the globulitic core zone in the thin slab is greater, the closer the electromagnetic stirrer is arranged on the meniscus of the thin slab strand or on the bath mirror. At the same time, however, it must be ensured that the electromagnetic stirrer is also effective in the lower region of the mold, so that an early and rapid reduction of overheating in the strand interior is achieved, and the currents generated in the metallic melt by the electromagnetic stirrer not to amplified Badspiegelschwankungen and not lead to enlarged local Badspiegelüberhöhungen in the mold. It has been found that the electromagnetic stirrer for this purpose should advantageously be arranged along the
Die erfindungsgemäße Vorrichtung dient insbesondere zur Herstellung von Dünnbrammen im Stranggussverfahren und daraus gefertigtem Warmband oder Kaltband. Das Warmband oder Kaltband wird insbesondere zur Herstellung von Elektroblechen (nicht kornorientiert oder kornorientiert) oder Blechen höherfester Stähle mit Streckgrenzenwerten größer als 400 Megapascal (bspw. Vergütungsstahl) verwendet. Eine Dünnbramme im Sinne der vorliegenden Erfindung umfasst insbesondere eine Bramme mit einer Dicke zwischen von 40 bis 120 Millimeter.The device according to the invention is used in particular for the production of thin slabs in the continuous casting process and hot strip or cold strip produced therefrom. The hot strip or cold strip is used in particular for the production of electrical sheets (not grain-oriented or grain-oriented) or sheets of higher-strength steels with yield strength values greater than 400 megapascals (for example tempered steel). A thin slab in the sense of In particular, the present invention includes a slab having a thickness of between 40 to 120 millimeters.
Gemäß einer weiteren bevorzugten Ausführungsform der vorliegenden Erfindung ist vorgesehen, dass der elektromagnetische Rührer einen Linearfeldrührer zur Erzeugung eines elektromagnetischen Wanderfeldes im Bereich des Dünnbrammenstrangs umfasst, wobei die Laufrichtung des elektromagnetischen Wanderfeldes parallel zur zweiten Querrichtung ausgerichtet ist. Der elektromagnetische Rührer ist insbesondere derart konfiguriert, dass ein erstes Subfeld des elektromagnetischen Wanderfelds vom Zentrum des Dünnbrammenstrangs zu einem ersten Randbereich des Dünnbrammenstrangs läuft und ein zweites Subfeld des elektromagnetischen Wanderfelds vom Zentrum zu einem dem ersten Randbereich gegenüberliegenden zweiten Randbereich des Dünnbrammenstrangs läuft. Dieses elektromagnetische Wanderfeld wird zwischen 1 und 60 Sekunden, vorzugsweise zwischen 1 und 10 Sekunden gehalten. Danach wird es umgekehrt, so dass das erste Subfeld vom ersten Randbereich des Dünnbrammenstrangs und das zweite Subfeld vom zweiten, dem ersten Randbereich gegenüberliegendem Randbereich des Dünnbrammenstrangs zum Zentrum des Dünnbrammenstrangs laufen. Auch dieses Feld wird zwischen 1 und 60 Sekunden, vorzugsweise zwischen 1 und 10 Sekunden gehalten. Danach beginnt der Zyklus wieder von vorne. In vorteilhafter Weise werden somit eine gleichmäßige und symmetrische Strömung im Inneren des Strangs und somit auch eine gleichmäßige Abfuhr der Überhitzung erzielt. Einerseits soll hierdurch eine homogene Gefügeverfeinerung im Stranginneren und andererseits ein gleichmäßiges Strangschalenwachstum über die Strangbreite herbeigeführt werden. Auf diese Weise wird verhindert, dass Strangdurchbrüche oder Oberflächen-Längsrisse entstehen.According to a further preferred embodiment of the present invention, it is provided that the electromagnetic stirrer comprises a linear field stirrer for generating an electromagnetic traveling field in the region of the thin slab strand, wherein the traveling direction of the electromagnetic traveling field is aligned parallel to the second transverse direction. In particular, the electromagnetic stirrer is configured such that a first subfield of the traveling electromagnetic field travels from the center of the thin slab strand to a first edge region of the thin slab strand and a second subfield of the traveling electromagnetic field travels from the center to a second edge region of the thin slab strand opposite to the first edge region. This electromagnetic traveling field is held between 1 and 60 seconds, preferably between 1 and 10 seconds. Thereafter, it is reversed, so that the first sub-field from the first edge region of the thin slab strand and the second sub-field from the second, the first edge region opposite edge region of the thin slab strand run to the center of the thin slab strand. Also this field is held between 1 and 60 seconds, preferably between 1 and 10 seconds. Then the cycle starts again from the beginning. Advantageously, thus a uniform and symmetrical flow inside the strand and thus a uniform dissipation of overheating are achieved. On the one hand, this is intended to bring about homogeneous microstructural refinement in the strand interior and, on the other hand, uniform strand shell growth over the strand width. In this way it is prevented that strand breaks or surface longitudinal cracks occur.
Gemäß einer weiteren bevorzugten Ausführungsform der vorliegenden Erfindung ist vorgesehen, dass der elektromagnetische Rührer derart eingestellt wird, dass die durch den Rührer erzeugte Strömungsgeschwindigkeit der metallischen Schmelze mindestens 0,2 Meter pro Sekunde oder maximal 0,7 Meter pro Sekunde beträgt und insbesondere zwischen 0,2 bis 0,7 Meter pro Sekunde liegt. Auf diese Weise wird sichergestellt, dass einerseits das Strangschalenwachstum an der Strangschmalseite nicht zu stark geschwächt wird (Verringerung der Strangdurchbruchgefahr) und andererseits starke Elementverarmungen (sogenannte weiße Bänder, d.h. Verarmung an C, Mn, Si, P, S, etc.) an der Erstarrungsfront im Wirkbereich des Rührers vermieden werden. Es hat sich gezeigt, dass die Strömungsgeschwindigkeit nicht kleiner als 0,2 Meter pro Sekunde sein sollte, weil ansonsten keine ausreichende Gefügeverfeinerung erreicht werden kann. Als nicht ausreichend kann dabei beispielsweise eine globulitische Kernzone angesehen werden, deren Ausdehnung in Dickenrichtung weniger als 30 % beträgt. Die Strömungsgeschwindigkeit sollte ferner nicht größer als 0,7 Meter pro Sekunde sein, um eine Verarmung der Schmelze an Legierungselementen im Bereich der Erstarrungsfront zu vermeiden. Die Verarmung der Schmelze an Legierungselementen im Bereich der Erstarrungsfront ist im erstarrten Material messbar. Dieses Phänomen wird als "weiße Bänder" oder "weiße Streifen" bezeichnet. Weiße Bänder führen zu inhomogenen Eigenschaften des Endprodukts.According to a further preferred embodiment of the present invention, it is provided that the electromagnetic stirrer is adjusted such that the flow velocity of the metallic melt produced by the stirrer is at least 0.2 meters per second or at most 0.7 meters per second, and in particular between 0, 2 to 0.7 meters per second. In this way, it is ensured that on the one hand the strand shell growth on the narrow side of the strand is not weakened too much (reducing the Stranddurchbruchgefahr) and on the other hand strong element depletion (so-called white bands, ie depletion of C, Mn, Si, P, S, etc.) on the Solidification front in the effective range of the stirrer can be avoided. It has been shown that the flow rate should not be less than 0.2 meters per second, because otherwise sufficient structural refinement can not be achieved. For example, a globulitic core zone can not be considered sufficient. whose thickness expansion is less than 30%. The flow rate should also be no greater than 0.7 meters per second to avoid depletion of the melt on alloying elements in the region of the solidification front. The depletion of the melt on alloying elements in the area of the solidification front can be measured in the solidified material. This phenomenon is called "white bands" or "white stripes". White bands lead to inhomogeneous properties of the final product.
Gemäß einer weiteren bevorzugten Ausführungsform der vorliegenden Erfindung ist vorgesehen, dass die elektromagnetische Bremse in der oberen Hälfte der Kokille, 20 bis 150 Millimeter, vorzugsweise 25 bis 100 Millimeter und besonders bevorzugt im Wesentlichen 75 Millimeter von einer Oberfläche des Dünnbrammenstrangs entlang der ersten Querrichtung beabstandet ist. Unter dem vorgenannten Abstand ist im Sinne der vorliegenden Erfindung insbesondere der kleinste Abstand zwischen der elektromagnetischen Bremse und der Strangoberfläche zu verstehen.According to a further preferred embodiment of the present invention, it is provided that the electromagnetic brake in the upper half of the mold, 20 to 150 millimeters, preferably 25 to 100 millimeters and particularly preferably substantially 75 millimeters from a surface of the thin slab strand along the first transverse direction is spaced , For the purposes of the present invention, the aforementioned distance is to be understood in particular to mean the smallest distance between the electromagnetic brake and the strand surface.
Weitere Einzelheiten, Merkmale und Vorteile der Erfindung ergeben sich aus den Zeichnungen, sowie aus der nachfolgenden Beschreibung von bevorzugten Ausführungsformen anhand der Zeichnungen. Die Zeichnungen illustrieren dabei lediglich beispielhafte Ausführungsformen der Erfindung, welche den wesentlichen Erfindungsgedanken nicht einschränken.Further details, features and advantages of the invention will become apparent from the drawings, as well as from the following description of preferred embodiments with reference to the drawings. The drawings illustrate only exemplary embodiments of the invention, which do not limit the essential inventive idea.
- Figur 1FIG. 1
- zeigt eine schematische Schnittbildansicht einer Vorrichtung zum Dünnbrammenstranggießen gemäß einer beispielhaften Ausführungsform der vorliegenden Erfindung.shows a schematic sectional view of a device for thin slab continuous casting according to an exemplary embodiment of the present invention.
- Figuren 2a und 2bFIGS. 2a and 2b
- zeigen schematische Detailansichten der Vorrichtung zum Dünnbrammenstranggießen gemäß der beispielhaften Ausführungsform der vorliegenden Erfindung im Bereich der Kokille und unterhalb der Kokille.show schematic detail views of the apparatus for thin slab continuous casting according to the exemplary embodiment of the present invention in the region of the mold and below the mold.
In den verschiedenen Figuren sind gleiche Teile stets mit den gleichen Bezugszeichen versehen und werden daher in der Regel auch jeweils nur einmal benannt bzw. erwähnt.In the various figures, the same parts are always provided with the same reference numerals and are therefore usually named or mentioned only once in each case.
In
Im vorliegenden Beispiel wird metallische Schmelze 2 aus einer Stahlgießpfanne 6 in einen Verteiler 3 überführt und von dem Verteiler 3 über ein Gießrohr 4 (Zuführmittel) in eine Kokille 5 der Vorrichtung 1 gegossen. Der Durchfluss durch das Gießrohr wird in Abhängigkeit vom Gießspiegel 7 in der Kokille 5 mit einem Stopfen 8 oder einem Schieber gesteuert. Die Kokille 5 umfasst eine Form mit einer nach unten offenen Durchlassöffnung mit rechteckigem Querschnitt. Die Breitseiten 28 der Form sind zwischen 40 und 120 Millimeter voneinander beabstandet, damit die Kokille 5 zum Gießen von Dünnbrammen geeignet ist. Die Form besteht aus wassergekühlten Kupferplatten, welche ein Erstarren der zugeführten metallischen Schmelze im Randbereich der Kokille 5 bewirken. In der Kokille 5 bildet sich somit aus der kontinuierlich zugeführten metallischen Schmelze 2 ein Dünnbrammenstrang 9 mit einer erstarrten Schale 10 und einem großenteils noch nicht erstarrten Querschnitt 11 innerhalb der erstarrten Schale 10. Optional oszilliert die Kokille 5, damit ein Anhaften der Strangoberfläche an der Kokille 5 verhindert wird. Der Dünnbrammenstrang 9 durchläuft die Kokille 5 entlang einer vertikalen Strangabzugsrichtung 15. Beim Verlassen der nach unten offenen Kokille 5 wird der Dünnbrammenstrang 9 von einem Transportsystem 12 (auch als Strangführungssystem bezeichnet) mit einer Vielzahl von Strangführungsrollen 13 aufgenommen und durch einen sogenannten Gießbogen 14 geführt. Der Dünnbrammenstrang 9 wird dabei bis zur vollständigen Durcherstarrung abgekühlt.In the present example,
Neben der Strangabzugsrichtung 15 sind eine erste Querrichtung 18 und eine zweite Querrichtung 30 in
Im oberen Bereich der Kokille 5 ist eine elektromagnetische Bremse 16 (EMBR: Electromagnetic Brake) angeordnet, welche die Strömungsgeschwindigkeit der metallischen Schmelze 2 im Inneren des bereits teilerstarrten Dünnbrammenstrangs 9 verlangsamt und damit Badspiegelschwankungen in der Kokille 5 verringert. Die elektromagnetische Bremse 16 umfasst im vorliegenden Beispiel zwei beidseitig des Dünnbrammenstrangs 9 angeordnete Spulen. Durch die elektromagnetische Bremse 16 wird ein elektromagnetisches Feld innerhalb der Kokille 5 erzeugt, dessen magnetische Flussdichte bevorzugt 0,1 bis 0,3 Tesla und besonders bevorzugt im Wesentlichen 0,2 Tesla beträgt. Durch das Abbremsen der Strömungsgeschwindigkeit der metallischen Schmelze 2 zwischen den teilerstarrten Randbereichen 10 des Dünnbrammenstrangs 9 können Gießspiegelschwankungen, sowie aus Gießspiegelschwankungen resultierende Oberflächenfehler (sogenannte Schalenfehler) und Innenfehler (bspw. Gießschlackeneinschlüsse) verhindert werden.In the upper region of the mold 5, an electromagnetic brake 16 (EMBR: Electromagnetic Brake) is arranged, which slows down the flow velocity of the
Unterhalb der Kokille 5 weist die erfindungsgemäße Vorrichtung 1 einen elektromagnetischen Rührer 17 zum Rühren von nichterstarrten Teilen des teilerstarrten Dünnbrammenstrangs 9 auf. Der elektromagnetische Rührer 17 umfasst im vorliegenden Beispiel einen Linearfeldrührer, welcher sich entlang einer der beiden Breitseiten 28 des Strangs erstreckt. Der Linearfeldrührer erzeugt über die Breite des Dünnbrammenstrangs 9 ein elektromagnetisches Wanderfeld 19 (siehe
Mit der vorstehend beschriebenen Vorrichtung bzw. dem vorstehend beschriebenen Verfahren werden Dünnbrammen insbesondere für Warmband oder Kaltband hergestellt. Das Warmband oder Kaltband wird insbesondere zur Herstellung von Elektroblechen (nichtkornorientiert oder kornorientiert) oder Blechen höherfester Stähle mit Streckgrenzenwerten größer als 400 Megapascal (bspw. Vergütungsstahl) verwendet.With the device described above or the method described above, thin slabs are produced in particular for hot strip or cold strip. The hot strip or cold strip is used in particular for the production of electrical sheets (non-grain oriented or grain oriented) or sheets of higher strength steels with yield strength values greater than 400 megapascals (eg tempered steel).
In
Anhand der oberen Figur ist jeweils zu sehen, dass das Zuführmittel das Gießrohr 4, welches in die in der Kokille 5 befindliche metallische Schmelze 2 eintaucht, und unterhalb des Gießspiegels 7 an dem Gießrohr 4 ausgebildete Ausgusslöcher 22 im unteren Teil des Gießrohres 4 umfasst. Die metallische Schmelze 2 wird mittels der Ausgusslöcher 22 unter einem Winkel zur Strangabzugsrichtung 15 des Dünnbrammenstranges 9 eingeleitet (siehe Strömungspfeile 23). Unterhalb der Kokille 5 ist das elektromagnetische Wanderfeld 19, induziert durch den nichtdargestellten elektromagnetischen Rührer 17, angeordnet. Der elektromagnetische Rührer 17, der unterhalb der Kokille 5 angeordnet ist, erzeugt unterhalb der Kokille 5 das elektromagnetische Wanderfeld 19, welches wiederum Strömungen bewirkt, die bis in die Kokille 5 reichen können - unter Umständen sogar bis zum Badspiegel. Bei dem Ausführungsbeispiel gemäß
In der unteren Darstellung von
Alternativ wird das elektromagnetische Wanderfeld 19 nicht in zwei Subfelder 24, 25 aufgeteilt, sondern läuft entlang der zweiten Querrichtung 30 zyklisch zwischen dem ersten Randbereich 20 des Dünnbrammenstrangs 9 und dem gegenüberliegenden zweiten Randbereich 21 des Dünnbrammenstrangs 9 hin und her. Dieses Ausführungsbeispiel ist beispielhaft in
Die nachfolgenden Ausführungsbeispiele wurden mit einer Vorrichtung gemäß
Ein Maß für den Erfolg der Verfeinerung des Erstarrungsgefüges im Inneren des Dünnbrammenstrangs ist der Anteil der globulitischen Kernzone (GKZ). Die Ausdehnung der globulitischen Kernzone in Prozent ist definiert als GKZ (%) = DGKZ (mm) / D (mm) ▪ 100 mit DGKZ = Dicke der globulitischen Kernzone und D = Brammendicke.A measure of the success of the refinement of the solidification structure inside the thin slab strand is the share of the globulitic core zone (GCC). The percent expansion of the globulitic core zone is defined as GKZ (%) = D GKZ (mm) / D (mm) ▪ 100 with D GKZ = globulitic core zone thickness and D = slab thickness.
Es wurde daher ein Versuch mit der Stahlsorte S420MC, einer Gießgeschwindigkeit von 5 Meter pro Minute, einer Überhitzung im Tundish von 30 Kelvin, einer Strangdicke von 65 Millimetern, einer Strangbreite von 1550 Millimetern und einer Kokillenhöhe von 1100 Millimetern durchgeführt, bei welchem die elektromagnetische Bremse (EMBR) in der oberen Hälfte der Kokille und der elektromagnetische Rührer (EMS) unterhalb der Kokille hinter amagnetischen Rollen des Transportsystems angeordnet war. Der elektromagnetische Rührer bzw. das elektromagnetische Wechselfeld des elektromagnetischen Rührers war in einem Abstand von 2960 Millimeter vom Gießspiegel angeordnet. Dabei wurden die in der folgenden Tabelle aufgeführten Ergebnisse erzielt:
Die Testreihen belegen, dass durch das Zuschalten eines unterhalb der Kokille angeordneten elektromagnetischen Rührers der Anteil der globulitischen Kernzone (GKZ) von 0 bis 10 Prozent auf einen Anteil von 40 bis 60 Prozent anwächst.The test series prove that by adding an electromagnetic stirrer arranged below the mold, the proportion of the globulitic core zone (GKZ) increases from 0 to 10 percent to a proportion of 40 to 60 percent.
Es wurde ein Zusammenhang zwischen Überhitzung der Stahlschmelze im Tundish und dem Anteil der globulitischen Kernzone einerseits und der daraus resultierenden Längsstreifigkeit am Fertigband bei Dynamostählen und der Mittenseigerung experimentell an Dynamostählen mit 2,4 % Silizium ermittelt:
Hieraus folgt, dass zur Vermeidung von Längsstreifigkeit und zur Verringerung der Mittenseigerung der Anteil der globulitischen Kernzone (GKZ) wenigstens 30 Prozent und vorzugsweise größer als 50 Prozent sein sollte. Eine Überhitzung von weniger als 20 K ist jedoch zu vermeiden, da andernfalls Probleme in Form von Zusetzungen der Tauchrohre in der Kokille (sogenannten "Clogging") auftreten würden, woraus Strangoberflächenfehler oder sogar Strangdurchbrüche resultieren können.It follows that in order to avoid longitudinal streaks and to reduce the center of gravity, the share of the globulitic core zone (CCS) should be at least 30 percent and preferably greater than 50 percent. Overheating of less than 20 K is to be avoided, however, as problems would otherwise occur in the form of clogging of the dip tubes in the mold, which may result in strand surface defects or even strand breakthroughs.
Nachfolgend wird am Beispiel für den Dynamostahl mit 2,4 % Silizium und Dünnbrammen mit einer Dicke von 63 Millimetern, einer Überhitzung im Tundish von 30 Kelvin, einer Strangbreite von 1550 Millimetern und einer Kokillenhöhe von 1100 Millimetern, der Gießspiegel lag 1000 Millimeter oberhalb der Kokillenunterseite, die Rührfrequenz betrug 6 Hz, die Strömungsgeschwindigkeit an der Erstarrungsfront betrug 0,4 m/s, gezeigt, dass durch eine entsprechende Wahl des Abstands zwischen dem Gießspiegel und dem elektromagnetischen Rührer (EMS) der erforderliche Anteil der globulitischen Kernzone (GKZ) von wenigstens 30 Prozent und vorzugsweise mindestens 50 Prozent bei unterschiedlichen Gießgeschwindigkeiten VG erzielt werden kann:
Die vorstehenden Messreihen zeigen, dass der elektromagnetische Rührer bei den für Dünnbrammen-Stranggießanlagen üblichen Gießgeschwindigkeiten (VG) zwischen 4 und 6 m/min für einen Anteil der globulitischen Kernzone von 50 Prozent zwischen 2,6 und 3,8 Meter, von 60 Prozent zwischen 1,7 und 2,5 Meter unterhalb des Badspiegels der Kokille angeordnet sein muss. Befriedigende Ergebnisse werden aber auch schon mit einem Abstand des elektromagnetischen Rührers vom Badspiegel zwischen 3,6 und 7,3 Metern erreicht.The above series of measurements show that at the casting speeds (V G ) typical for thin slab casters, the electromagnetic stirrer is between 4 and 6 m / min for a 50 percent globulite core zone between 2.6 and 3.8 meters, 60 percent between 1.7 and 2.5 meters below the bath level of the mold must be arranged. Satisfactory results are achieved even with a distance of the electromagnetic stirrer from the bath level between 3.6 and 7.3 meters.
Der Abstand zwischen der Kokille bzw. der Kokillenunterseite und dem elektromagnetischen Rührer liegt somit vorteilhafterweise zwischen 20 und 7.000 Millimetern und bevorzugt zwischen 50 und 3.000 Millimetern. Alternativ ist auch ersichtlich, dass ein Abstand zwischen 100 und 7.000 Millimetern, zwischen 500 und 6.500 Millimetern, zwischen 700 und 6.300 Millimetern, zwischen 700 und 4.400 Millimetern oder zwischen 700 und 2.800 Millimetern besonders vorteilhaft ist.The distance between the mold or the base of the mold and the electromagnetic stirrer is thus advantageously between 20 and 7,000 millimeters and preferably between 50 and 3,000 millimeters. Alternatively, it can also be seen that a distance between 100 and 7,000 millimeters, between 500 and 6,500 millimeters, between 700 and 6,300 millimeters, between 700 and 4,400 millimeters or between 700 and 2,800 millimeters is particularly advantageous.
- 11
- Vorrichtungdevice
- 22
- metallische Schmelzemetallic melt
- 33
- Verteilerdistributor
- 44
- Gießrohrcasting tube
- 55
- Kokillemold
- 66
- Stahlgießpfannesteel ladle
- 77
- Gießspiegelmeniscus
- 88th
- StopfenPlug
- 99
- DünnbrammenstrangThin slab
- 1010
- Erstarrte StrangschaleFrozen strand shell
- 1111
- Nichterstarrter QuerschnittNon-solid cross-section
- 1212
- Transportsystemtransport system
- 1313
- StrangführungsrolleStrand guide roller
- 1414
- Gießbogencasting bow
- 1515
- StrangabzugsrichtungStrand withdrawal direction
- 1616
- Elektromagnetische BremseElectromagnetic brake
- 1717
- Elektromagnetischer RührerElectromagnetic stirrer
- 1818
- Erste Querrichtung (verläuft senkrecht zur Strangabzugsrichtung und parallel zur Strangoberflächennormalen der Brammenbreitseite)First transverse direction (runs perpendicular to the strand withdrawal direction and parallel to the strand surface normal of the slab broadside)
- 1919
- Elektromagnetisches WanderfeldElectromagnetic traveling field
- 2020
- Erster RandbereichFirst edge area
- 2121
- Zweiter RandbereichSecond edge area
- 2222
- Ausgusslöcher im unteren Teil des GießrohresSpouts in the lower part of the pouring tube
- 2323
- Strömungspfeilarrow flow
- 2424
- Erstes SubfeldFirst subfield
- 2525
- Zweites SubfeldSecond subfield
- 2626
- Zentrumcenter
- 2727
- Bewegungspfeilmovement arrow
- 2828
- Breitseitenbroadsides
- 2929
- KokillenunterseiteKokillenunterseite
- 3030
- Zweite Querrichtung (verläuft senkrecht zur Strangabzugsrichtung und parallel zur Strangoberfläche auf der Brammenbreitseite bzw. verläuft senkrecht zur Strangabzugsrichtung und senkrecht zur ersten Querrichtung)Second transverse direction (runs perpendicular to the strand withdrawal direction and parallel to the strand surface on the slab broad side or runs perpendicular to the strand withdrawal direction and perpendicular to the first transverse direction)
- 3131
- KokillenoberseiteKokillenoberseite
Claims (17)
- Method for the continuous casting of thin slabs comprising the method steps of:- feeding a molten metal (2) into a mold (5),- molding a partially solidified thin-slab strand (9) from the molten metal (2) in the mold (5),- reducing the flow rate of the molten metal (2) in the partially solidified thin-slab strand (9) by means of an electromagnetic brake (16) arranged in the region of the mold (5) and- removing the partially solidified thin-slab strand (9) from the mold (5) by means of a strand guiding system (12),characterized in that- unsolidified parts of the partially solidified thin-slab strand (9) are stirred by means of an electromagnetic stirrer (17) arranged underneath the mold (5) downstream along the strand takeoff direction (15) of the thin-slab strand (9),- a traveling electromagnetic field (19) being produced by means of the electromagnetic stirrer (17) in a region of the thin-slab strand (9) that lies at a distance from the mold (5) of between 20 and 7000 millimeters along the strand takeoff direction (15).
- Method according to Claim 1, wherein the traveling electromagnetic field (19) is generated in a region of the thin-slab strand (9) that is at a distance from the mold (5) of between 50 and 3000 millimeters along the strand takeoff direction (15).
- Method according to one of the preceding claims, wherein an electromagnetic field is generated within the mold (5) by means of the electromagnetic brake (16), wherein, in the upper half of the mold, the electromagnetic brake (16) is at a distance from a surface of the thin-slab strand of preferably between 20 and 150 millimeters along a first transverse direction (18), which runs perpendicularly to the strand takeoff direction (15) and parallel to a strand surface normal on a broad side (28) of the thin-slab strand (9).
- Method according to one of the preceding claims, wherein the electromagnetic stirrer (17) is set in such a way that, along a second transverse direction (30), which runs perpendicularly to the strand takeoff direction (15) and perpendicularly to the first transverse direction (18), the traveling electromagnetic field (19) runs from a first outer region (20) of the thin-slab strand (9) to a second outer region (21) of the thin-slab strand (9) that is opposite from the first outer region (20).
- Method according to one of Claims 1 to 3, wherein a bidirectional, symmetrical traveling electromagnetic field (19) is generated over the width of the thin-slab strand (9) by means of the electromagnetic stirrer (17), the electromagnetic stirrer (17) being set in such a way that a first subfield (24) of the traveling electromagnetic field (19) runs from a center (26) of the thin-slab strand (9) to a first outer region (20) of the thin-slab strand (9) and that a second subfield (25) of the traveling electromagnetic field (19) runs from the center (26) of the thin-slab strand (9) to a second outer region (21) of the thin-slab strand (9) that is opposite from the first outer region (20).
- Method according to one of Claims 1 to 3, wherein a bidirectional, symmetrical traveling electromagnetic field (19) is generated over the width of the thin-slab strand (9) by means of the electromagnetic stirrer (17), the electromagnetic stirrer (17) being set in such a way that a first subfield (24) of the traveling electromagnetic field (19) runs from a first outer region (20) of the thin-slab strand (9) to a center (26) of the thin-slab strand (9) and that a second subfield (25) of the traveling electromagnetic field (19) runs from a second outer region (21) of the thin-slab strand (9) that is opposite from the first outer region (20) to the center (26) of the thin-slab strand (9).
- Method according to one of the preceding claims, wherein a traveling electromagnetic field of which the magnetic flux density is on average preferably 0.1 to 0.6 tesla, particularly preferably 0.3 to 0.5 tesla and most particularly preferably substantially 0.4 tesla, is generated in the region of the thin-slab strand (9) by means of the electromagnetic stirrer (17).
- Method according to one of the preceding claims, wherein the electromagnetic stirrer (17) is set in such a way that the flow rate of the unsolidified parts in the partially solidified thin-slab strand (9) is at least 0.2 meters per second or at most 0.7 meters per second and preferably between 0.2 and 0.7 meters per second.
- Method according to one of the preceding claims, wherein the electromagnetic stirrer (17) is set in such a way that the stirring frequency is at least 0.1 Hz or at most 10 Hertz and preferably between 0.1 and 10 Hz.
- Method according to one of the preceding claims, wherein an electromagnetic field of which the magnetic flux density is preferably 0.1 to 0.3 tesla, particularly preferably 0.15 to 0.25 tesla and most particularly preferably 0.2 tesla, is generated within the mold (5) by means of the electromagnetic brake (16).
- Method according to one of the preceding claims, wherein the method is used for producing thin slabs for the production of hot strip or cold strip, in particular for producing electric sheets or sheets of higher-strength steels preferably with yield strength values greater than 400 megapascals.
- Device (1) for the continuous casting of thin slabs, in particular by means of a method according to one of the preceding claims, comprising- a feeding means for supplying a molten metal (2),- a mold (5) for molding a partially solidified thin-slab strand (9) from the supplied molten metal (2),- an electromagnetic brake (16), arranged in the region of the mold (5), for reducing the flow rate of the molten metal (2) inside the partially solidified thin-slab strand (9) and- a strand guiding system (12) for removing the partially solidified thin-slab strand (9) from the mold (2),characterized in that- the device (1) comprises an electromagnetic stirrer (17), arranged underneath the mold (5) downstream along the strand takeoff direction (15) of the thin-slab strand (9), for stirring unsolidified parts of the partially solidified thin-slab strand (9), that is at a distance from the mold (5) of between 20 and 7000 millimeters along the strand takeoff direction (15).
- Device (1) according to Claim 12, wherein the electromagnetic stirrer (17) is at a distance from the mold (5) of between 50 and 3000 millimeters along the strand takeoff direction (15).
- Device (1) according to either of Claims 12 and 13, wherein the electromagnetic stirrer (17) comprises a linear field stirrer for generating a traveling electromagnetic field (19) in the region of the thin-slab strand (9), the running direction of the traveling electromagnetic field (19) being aligned perpendicularly to the strand takeoff direction (15) and parallel to a second transverse direction (30), which runs perpendicularly to the strand takeoff direction (15) and parallel to a strand surface on a broad side (28) of the thin-slab strand (9), and the running direction of the traveling electromagnetic field (19) being reversible.
- Device (1) according to one of Claims 12 to 14, wherein the electromagnetic stirrer (17) is at a distance from a surface of the thin-slab strand (9) of 20 to 1000 millimeters, preferably 20 to 200 millimeters and particularly preferably 20 to 40 millimeters, along a first transverse direction (18), which runs perpendicularly to the strand takeoff direction (15) and perpendicularly to the second transverse direction (30).
- Device (1) according to one of Claims 12 to 15, wherein the electromagnetic stirrer (17) is configured in such a way that the flow rate of the unsolidified parts in the partially solidified thin-slab strand (9) is between 0.2 and 0.7 meters per second and/or that the stirring frequency is between 0.1 and 10 Hz.
- Device (1) according to one of Claims 12 to 15, wherein, in the upper half of the mold, the electromagnetic brake (16) is at a distance from a surface of the thin-slab strand of preferably between 20 and 150 millimeters along the first transverse direction (18).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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DE102014105870.4A DE102014105870A1 (en) | 2014-04-25 | 2014-04-25 | Process and apparatus for thin slab continuous casting |
PCT/EP2015/058130 WO2015162039A1 (en) | 2014-04-25 | 2015-04-15 | Method and device for thin-slab strand casting |
Publications (2)
Publication Number | Publication Date |
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EP3134220A1 EP3134220A1 (en) | 2017-03-01 |
EP3134220B1 true EP3134220B1 (en) | 2019-09-04 |
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EP15716054.0A Active EP3134220B1 (en) | 2014-04-25 | 2015-04-15 | Method and device for thin-slab strand casting |
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US (1) | US10486228B2 (en) |
EP (1) | EP3134220B1 (en) |
KR (1) | KR20160146914A (en) |
CN (1) | CN106536087B (en) |
DE (1) | DE102014105870A1 (en) |
ES (1) | ES2756700T3 (en) |
WO (1) | WO2015162039A1 (en) |
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DE102015223788A1 (en) * | 2015-11-30 | 2017-06-01 | Sms Group Gmbh | Method of continuous casting of a metal strand and cast strand obtained by this method |
SK7957Y1 (en) * | 2016-04-29 | 2017-12-04 | Pokusova Marcela | The control method of the solidification process of the continuous casting of metals and alloys and device for carrying out the method. |
JP6879320B2 (en) * | 2018-05-31 | 2021-06-02 | Jfeスチール株式会社 | Manufacturing method of grain-oriented electrical steel sheet |
JP7151247B2 (en) * | 2018-07-27 | 2022-10-12 | 日本製鉄株式会社 | Flow controller for thin slab continuous casting and thin slab continuous casting method |
CN114932206B (en) * | 2022-06-08 | 2023-05-16 | 沈阳工程学院 | Independently controllable composite magnetic field device and method for controlling molten metal flow in crystallizer |
CN115194107B (en) * | 2022-07-13 | 2023-05-16 | 沈阳工程学院 | Multi-stage independent adjustable composite magnetic field device and method for controlling metal liquid flow |
CN115722639A (en) * | 2022-12-06 | 2023-03-03 | 湖南中科电气股份有限公司 | Fan-shaped section for sheet billet belt electromagnetic stirring device |
Citations (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0009803B1 (en) | 1978-10-06 | 1983-03-16 | Concast Holding Ag | Method for continuously casting steel |
EP0040383B1 (en) | 1980-05-19 | 1983-10-12 | Asea Ab | Method and apparatus for stirring the molten metal in a continuous-casting strand |
EP0092126A1 (en) | 1982-04-19 | 1983-10-26 | Asea Ab | Method of stirring the non-solidified areas in a cast billet |
DE3113192C2 (en) | 1980-04-02 | 1984-11-29 | Kobe Steel, Ltd., Kobe, Hyogo | Method for electromagnetic stirring of molten steel in several areas of a continuous caster |
JPS61193755A (en) | 1985-02-25 | 1986-08-28 | Toshiba Corp | Electromagnetic stirring method |
JPS61255749A (en) | 1985-05-08 | 1986-11-13 | Kawasaki Steel Corp | Method for decreasing non-metallic inclusion in continuously cast slab |
EP0401504B1 (en) | 1989-04-27 | 1994-07-06 | Kawasaki Steel Corporation | Apparatus and method for continuous casting |
EP0698434A1 (en) | 1994-08-22 | 1996-02-28 | Sms Schloemann-Siemag Aktiengesellschaft | Installation for continuous casting of thin slabs |
JPH08323454A (en) | 1995-05-30 | 1996-12-10 | Sumitomo Metal Ind Ltd | Continuous casting method for wide and thin slab |
DE19542211A1 (en) | 1995-11-13 | 1997-05-15 | Schloemann Siemag Ag | Electromagnetic stirring device for a slab casting mold |
EP0815987A1 (en) | 1996-06-28 | 1998-01-07 | Sms Schloemann-Siemag Aktiengesellschaft | Electromagnetic stirrer and brake for a continuous casting apparatus |
JP2000000648A (en) | 1998-06-16 | 2000-01-07 | Kawasaki Steel Corp | Method and apparatus for continuously casting steel |
JP2001087846A (en) | 1999-09-22 | 2001-04-03 | Kawasaki Steel Corp | Continuous casting method of steel slab and continuous casting device |
DE10020703A1 (en) | 2000-04-27 | 2001-10-31 | Sms Demag Ag | Process for continuously casting thin slabs comprises inducing ultrasound waves in the bath mirror region of the mold and electromagnetic fields in the regions below it and overlapping it |
JP2003326339A (en) | 2002-05-13 | 2003-11-18 | Nippon Steel Corp | Facility and method for continuously casting thin slab |
CN1142045C (en) | 1999-09-22 | 2004-03-17 | 大连理工大学 | Continuous metal casting method with applied composite electromagnetic field |
DE69824749T2 (en) | 1997-09-03 | 2005-08-04 | Abb Ab | Method and device for continuous or semi-continuous casting of metal |
CN201596751U (en) | 2009-12-25 | 2010-10-06 | 鞍钢股份有限公司 | Composite electromagnetic stirring device |
DE102009056000A1 (en) | 2009-08-28 | 2011-03-03 | Sms Siemag Ag | Casting molten metal, preferably molten steel materials in form of strand in mold of continuous casting machine, useful for producing slabs- and thin slab products, comprises introducing molten metal through dipping tube |
DE212009000056U1 (en) | 2008-05-20 | 2011-04-21 | Siemens Vai Metals Technologies Gmbh | Continuous casting plant for producing thick slabs |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2810491A1 (en) | 1978-03-08 | 1979-09-20 | Aeg Elotherm Gmbh | METHOD FOR INFLUENCING THE SOLIDIZATION OF A MELT DURING CONTINUOUS CASTING |
FR2437900A1 (en) * | 1978-10-05 | 1980-04-30 | Siderurgie Fse Inst Rech | CONTINUOUS CASTING PROCESS FOR METALS WITH BREWING IN THE SECONDARY COOLING AREA |
SE418934B (en) * | 1979-10-31 | 1981-07-06 | Asea Ab | PROCEDURE FOR REMOVING NON-SUBSTANCED PARTS IN A CASTING STRING FROM A CASTING MACHINE |
DE3322891A1 (en) * | 1983-06-23 | 1985-01-03 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Apparatus for the electrodynamic stirring of the liquid pool of a metal slab |
JPS60162559A (en) * | 1984-01-31 | 1985-08-24 | Nippon Steel Corp | Method for controlling electromagnetic stirring in continuous casting machine |
JPS6349352A (en) * | 1986-08-13 | 1988-03-02 | Hitachi Metals Ltd | Improvement method of internal quality in continuous casting billet for tool steel |
JP3180164B2 (en) * | 1992-02-04 | 2001-06-25 | 新日本製鐵株式会社 | Method and apparatus for improving internal quality of continuous cast slab |
DE10350076A1 (en) * | 2003-10-27 | 2005-06-02 | Siemens Ag | Apparatus and method for electromagnetic stirring or braking of metal casting, in particular steel casting |
KR101261691B1 (en) * | 2008-04-28 | 2013-05-06 | 신닛테츠스미킨 카부시키카이샤 | Method for continuous casting of steel and electromagnetic stirrer usable therefor |
JP5428780B2 (en) * | 2009-11-11 | 2014-02-26 | 新日鐵住金株式会社 | Steel continuous casting method |
-
2014
- 2014-04-25 DE DE102014105870.4A patent/DE102014105870A1/en active Pending
-
2015
- 2015-04-15 KR KR1020167032601A patent/KR20160146914A/en unknown
- 2015-04-15 CN CN201580022505.0A patent/CN106536087B/en active Active
- 2015-04-15 ES ES15716054T patent/ES2756700T3/en active Active
- 2015-04-15 WO PCT/EP2015/058130 patent/WO2015162039A1/en active Application Filing
- 2015-04-15 EP EP15716054.0A patent/EP3134220B1/en active Active
- 2015-04-15 US US15/303,179 patent/US10486228B2/en active Active
Patent Citations (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0009803B1 (en) | 1978-10-06 | 1983-03-16 | Concast Holding Ag | Method for continuously casting steel |
DE3113192C2 (en) | 1980-04-02 | 1984-11-29 | Kobe Steel, Ltd., Kobe, Hyogo | Method for electromagnetic stirring of molten steel in several areas of a continuous caster |
EP0040383B1 (en) | 1980-05-19 | 1983-10-12 | Asea Ab | Method and apparatus for stirring the molten metal in a continuous-casting strand |
EP0092126A1 (en) | 1982-04-19 | 1983-10-26 | Asea Ab | Method of stirring the non-solidified areas in a cast billet |
JPS61193755A (en) | 1985-02-25 | 1986-08-28 | Toshiba Corp | Electromagnetic stirring method |
JPS61255749A (en) | 1985-05-08 | 1986-11-13 | Kawasaki Steel Corp | Method for decreasing non-metallic inclusion in continuously cast slab |
EP0401504B1 (en) | 1989-04-27 | 1994-07-06 | Kawasaki Steel Corporation | Apparatus and method for continuous casting |
EP0698434A1 (en) | 1994-08-22 | 1996-02-28 | Sms Schloemann-Siemag Aktiengesellschaft | Installation for continuous casting of thin slabs |
JPH08323454A (en) | 1995-05-30 | 1996-12-10 | Sumitomo Metal Ind Ltd | Continuous casting method for wide and thin slab |
DE19542211A1 (en) | 1995-11-13 | 1997-05-15 | Schloemann Siemag Ag | Electromagnetic stirring device for a slab casting mold |
EP0815987A1 (en) | 1996-06-28 | 1998-01-07 | Sms Schloemann-Siemag Aktiengesellschaft | Electromagnetic stirrer and brake for a continuous casting apparatus |
DE69824749T2 (en) | 1997-09-03 | 2005-08-04 | Abb Ab | Method and device for continuous or semi-continuous casting of metal |
JP2000000648A (en) | 1998-06-16 | 2000-01-07 | Kawasaki Steel Corp | Method and apparatus for continuously casting steel |
JP2001087846A (en) | 1999-09-22 | 2001-04-03 | Kawasaki Steel Corp | Continuous casting method of steel slab and continuous casting device |
CN1142045C (en) | 1999-09-22 | 2004-03-17 | 大连理工大学 | Continuous metal casting method with applied composite electromagnetic field |
DE10020703A1 (en) | 2000-04-27 | 2001-10-31 | Sms Demag Ag | Process for continuously casting thin slabs comprises inducing ultrasound waves in the bath mirror region of the mold and electromagnetic fields in the regions below it and overlapping it |
JP2003326339A (en) | 2002-05-13 | 2003-11-18 | Nippon Steel Corp | Facility and method for continuously casting thin slab |
DE212009000056U1 (en) | 2008-05-20 | 2011-04-21 | Siemens Vai Metals Technologies Gmbh | Continuous casting plant for producing thick slabs |
DE102009056000A1 (en) | 2009-08-28 | 2011-03-03 | Sms Siemag Ag | Casting molten metal, preferably molten steel materials in form of strand in mold of continuous casting machine, useful for producing slabs- and thin slab products, comprises introducing molten metal through dipping tube |
CN201596751U (en) | 2009-12-25 | 2010-10-06 | 鞍钢股份有限公司 | Composite electromagnetic stirring device |
Non-Patent Citations (1)
Title |
---|
PETER HEINRICH, ET AL: "Productivity, quality and resource efficiency of CSP technology", CONTINUOUS CASTING, MILLENNIUM STEEL, 1 January 2004 (2004-01-01), pages 156 - 161, XP055756861 |
Also Published As
Publication number | Publication date |
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DE102014105870A1 (en) | 2015-10-29 |
US20170036267A1 (en) | 2017-02-09 |
KR20160146914A (en) | 2016-12-21 |
ES2756700T3 (en) | 2020-04-27 |
CN106536087B (en) | 2020-07-24 |
EP3134220A1 (en) | 2017-03-01 |
US10486228B2 (en) | 2019-11-26 |
CN106536087A (en) | 2017-03-22 |
WO2015162039A1 (en) | 2015-10-29 |
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