Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/12—Accessories for subsequent treating or working cast stock in situ
  • B22D11/124—Accessories for subsequent treating or working cast stock in situ for cooling
• • 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
  • B22D11/22—Controlling or regulating processes or operations for cooling cast stock or mould
  • B22D11/225—Controlling or regulating processes or operations for cooling cast stock or mould for secondary cooling

Definitions

• the invention relates to a method for optimizing edge areas of the Strand surfaces in continuous casting plants with mold cast blocks, billets Slabs or the like, in particular thin slabs.
• oscillation marks On the strand surfaces, for example, in the edge areas of the thin slabs are alternating Sections without or alternating with relatively weak to pronounced There are oscillation marks. These oscillation marks are in the Edge area of the rolled strip visible as a shadow and restrict it Use one. Such shadows usually have a width of up to 250 mm, starting from the band edge.
• the casting powder / granulate layer there is also alternating in the edge area of the Casting format no or an alternating weak to strong casting powder ejection to observe. It is believed that between the strength of the casting powder and the creation of the oscillation marks consists.
• Document WO 02/060619 A1 describes a strand guide segment for guiding and cooling the cast strand of a continuous casting installation, comprising a roller bridge formed with cross members and guide rollers between side walls and a coolant supply for the secondary cooling of the cast strand and the frame cooling, these having a coolant distribution and connectable to this Distribution pipes, spray pipes and spray nozzles at the ends are provided.
• the strand guide segment has water-conducting trusses with truss areas which are coupled by vertical chambers in such a way that for the middle area in accordance with the smallest strand width or for the first outer area in accordance with the mean strand width or for the second outer area in accordance with the maximum Strand width a coolant supply is provided.
• the coolant supply for the secondary cooling of the cast strand and the frame cooling consists of a water distribution and distributor pipes, spray pipes and spray nozzles connected to the end.
• Document DE 24 01 263 A1 discloses a cooling system for the secondary cooling section a continuous caster.
• the cooling system for the secondary cooling section in which the strand is cooled by means of spray water, is that its Edge areas are cooled less than the other areas, which achieves this that the spray width of the rays appearing on the strand surface thanks to adjustable covers between the spray nozzles and the strand is adjustable.
• the covers can be in the form of panels near the nozzle be arranged.
• JP 022 906 56 A discloses means for controlling the quantity of penetration of mold powder in the production of a cast strand and for reaching one excellent surface characteristics due to a distance between the mold and the solidified shell of the casting according to the material to be cast.
• the vertical oscillation is periodically transferred to a mold with a wide and narrow side.
• the clamping force of the upper and lower clamping means is increased or reduced in order to regulate the amount of mold powder penetrating between the mold and the solidified shell of the cast strand.
• Document JP 612 459 49 A discloses a method for eliminating the variable factors of harmful influences on the quality of a continuous cast product by maintaining the temperature of a melt in contact with the inner side walls of a mold, in particular in a meniscus position in the region of the solidification point of the melt or above it.
• the melt is fed into the mold from a funnel via an immersion tube.
• the melt is maintained at a temperature corresponding to or above the solidification point of the metal by generating heat from an inductor in the upper region of the mold, so that a completely molten metal layer is formed.
• This is then cooled for solidification by means of cooling water pipes in the subsequent area of the mold, until it is completely solidified.
• the cast strand is then cooled further in a cooling spray zone and pulled out of the mold by pinch rollers.
• the cast strand produced is free of oscillation marks and contains no non-metallic inclusions below the surface of the cast skin of the strand produced.
• Document BE 893 777 A discloses a method in which, in a continuous casting process, in particular for steel, the wall of the upper region of a mold is cooled in the area of nitration during metal solidification with a lower cooling intensity than the lower region of the mold.
• the different cooling can be achieved by two separate water cooling circuits, if necessary by supplying coolant with different thermal conductivity, by increasing the thickness of a powder coating or material covering at the corners of the mold, by heating the upper area of the mold or by using inserts with lower thermal conductivity than copper in the upper area of the mold.
• the different cooling effect reduces the tendency to form oscillation marks in the cast strand.
• the object of the invention to avoid or greatly reduce casting powder ejection in order to thus avoiding the oscillation marks that would otherwise be in the edge area of the rolled strip would be visible as shadows.
• the measure can be used, for example be preferably to switch off the spray water quantities in the spray ring or at least to reduce significantly below the current spray water quantities an increase in water vapor between the inner wall of the mold and the strand in the Avoid edge area of the casting format, leading to ejection of casting powder can lead.
• Rising water vapor between the inner wall of the mold and the strand reduces the heat transfer, at least in the edge area of the mold.
• An uneven heat flow density across the mold width has a negative impact on the surface quality.
• the amount of water spray between 0 and max. 50 l / min per meter of casting width.
• the spray water pressure is between 0 and Max. 2 bar.
• the method according to the invention is straightforward and efficient and it solves in an optimal way Way, the task of the invention.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Continuous Casting (AREA)

Applications Claiming Priority (4)

Publications (1)

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Cited By (1)

Citations (5)

• 2004
  • 2004-02-17 EP EP04003456A patent/EP1464422A1/fr not_active Ceased

Patent Citations (5)

Non-Patent Citations (4)

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