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
  • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
  • B22D11/0622—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars formed by two casting wheels
• • 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
  • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
  • B22D11/0637—Accessories therefor
  • B22D11/0697—Accessories therefor for casting in a protected atmosphere
• • 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
  • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
  • B22D11/0637—Accessories therefor
  • B22D11/064—Accessories therefor for supplying molten metal
  • B22D11/0642—Nozzles
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
  • B22D27/003—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting by using inert gases

Definitions

• the invention relates to a method for preventing the contact of oxygen with a molten metal during continuous casting, the molten metal flowing into a casting space delimited by walls and emerging from it as a strand, and a device for carrying out the method.
• Continuous casting results in the accumulation of molten metal in the casting room, which must be protected against reoxidation and its bath level from excessive heat radiation.
• the bath level is covered with casting powder or with an oil for this purpose.
• the invention aims to avoid these disadvantages and difficulties and has the object to provide a method of the type described above and a device for continuous casting, with which contact of oxygen with a molten metal can be prevented, which completely prevents reoxidation, u .zw. even if there is severe wear on the gaps between the walls forming the casting space.
• This object is achieved in a method of the type described in the introduction in that any gaps that may be trying to penetrate between the walls and / or oxygen adhering to the walls are suctioned off.
• a particularly efficient removal of the oxygen can advantageously be achieved in that the suction in several from the outside to the inside Suction stages arranged one behind the other take place, whereby the suction is expediently carried out with decreasing pressure from stage to stage from the outside inwards towards the casting chamber.
• the suction pressure in the suction stage closest to the casting chamber is set below 50 mbar, preferably below 10 mbar.
• an inert gas is expediently allowed to flow against the wall directly adjacent to the suction zone closest to the casting chamber on a wall delimiting the casting chamber, the pressure of the inert gas advantageously being increased by at least 10 mbar, preferably by more than 200 mbar the pressure of the neighboring suction stage.
• the inert gas is preferably blown against the wall in a plurality of inert gas stages which are arranged adjacent to the outside of the casting chamber.
• the inert gas is expediently blown onto the wall at a speed of at least 0.5 m / s, at most 10 m / s, preferably at more than 2 m / s.
• a casting method in which at least one wall is moved relative to the casting chamber in which at least one wall is moved relative to the casting chamber, according to a preferred embodiment, wall regions of this wall which are newly entering the casting chamber are freed of oxygen adhering to them by suction before the entry.
• the continuous casting is then advantageously carried out in the roll casting process, preferably in the two-roll casting process, that is to say that roll casting processes with only one casting roll, as described, for example, in EP-B-0 040 072, are also suitable for the process according to the invention.
• the method according to the invention can also be used when casting a molten metal on any moving heat sink, for example a caterpillar chain according to DE-A-36 02 594. It may also be for Chill molds with rigid walls are advantageous, for example, if the application of a mold powder is not possible or would be too expensive.
• a device with which contact of oxygen with a molten metal can be prevented during continuous casting wherein a casting space bounded by walls is filled with molten metal and a strand emerges from the casting space via a pouring gap in the pouring space, is characterized in that any between adjacent ones Walls existing gaps a suction device is provided for trying to penetrate through the gaps and / or for oxygen adhering to the walls.
• a device for the continuous casting of a metal strip preferably a steel strip, with two counter-rotating casting rolls with parallel adjacent roller axes and two side dams, which together form a casting space for the reception of molten metal and with a covering hood which is arranged above the casting space and this closes at the top, as well as with a sealing device that prevents the entry of air into the casting space along a gap formed by the cover and the rotating casting rollers
• the object on which the invention is based is advantageously achieved in that the sealing device has at least one atmospheric side in the vicinity of the Gap is arranged between the rotating casting rolls and the cover and extending parallel to the roll axis suction chamber.
• This sealing device has a particularly effective effect if it is formed by a plurality of suction chambers arranged next to one another in the circumferential direction of the casting rolls. It is advantageous here if each suction chamber is connected to an assigned suction pump or to a stage of a multi-stage suction pump via a suction line.
• the sealing device is designed as a serial multi-chamber system. This measure reduces the suction pressure in the direction of movement of the casting rolls from the suction chamber to the suction chamber. By a Corresponding coordination of the number of suction chambers to the peripheral speed of the casting rolls, a complete removal of the entrained air can be achieved.
• the sealing device is arranged at a defined distance from the casting roll surface and the gap formed by the sealing device and the casting roll surface is sealed at least on the input and output sides with touching seals, preferably brush or rubber lip seals.
• At least one of the suction chambers is additionally equipped with an inert gas purge.
• the device is improved in that an inert gas supply is arranged between the cover and the suction device, this inert gas supply being designed as a vacuum chamber with an opening directed against the casting rolls.
• the opening is advantageously designed as a nozzle which is directed obliquely towards the casting roll surface and inclined to the adjacent suction chamber.
• FIG. 1 shows a cross section through the two-roll zeng screenstrom with a sealing device according to a first embodiment
• Fig. 2 shows a second embodiment of the sealing device according to the invention
• FIG 3 shows a third embodiment of the sealing device according to the invention.
• the two-roll casting installation as shown schematically in section in FIG. 1, has two driven casting rolls 1, 2, the roll axes 3, 4 of which are arranged parallel to one another and are arranged in a horizontal plane.
• the two casting rolls 1, 2 rotating in opposite directions in the direction of the arrow 5, 6 are provided with internal cooling (not shown) for the casting roll shell, which forms the casting roll surface 7.
• side dams 8 are arranged sufficiently close to the casting rolls 1, 2.
• a casting chamber 9 is formed by the casting rolls 1, 2 and the side dams 8, into which melt 20 is introduced from a melt container or a distribution vessel (not shown) through a supply nozzle 11 provided with outlet openings 11, which forms a melt sump 12.
• the casting chamber 9 is bounded at the top, with respect to the casting rollers 1, 2 and with respect to the side dams 8 by a cover 13 which has a refractory lining 14 on the melt side in order to protect the melt 20 against excessive heat losses and against reoxidation from the atmospheric oxygen.
• a desired minimum gap 18 between the cover 13 and the casting rollers 1, 2 is set with a support device 15 for the cover 13, which is adjustable with respect to a stationary frame 16 with setting elements 17.
• the cover 13 is penetrated by the feed nozzle 10, with the smallest possible gap being provided between these components, which may be covered by a seal.
• a two-roll caster of this configuration it is possible to cast a thin metal strip, in particular a steel strip, in the thickness range from 1 mm to 12 mm, the melt 20 to be cast being introduced continuously into the casting space 9, as described at the beginning.
• the casting rolls 1, 2 rotating and cooling in opposite directions are increasingly formed Stronger shells, which are connected in the narrowest cross section between the casting rolls to form a band formed by the casting rolls.
• the thickness of the strip fed out by the casting rolls is determined by the distance between the two casting rolls.
• a sealing device 23 formed by a suction chamber 24 is on the atmosphere side in the vicinity of the gap 18 and at a short distance from the casting roll surface 7 arranged.
• the suction chamber 24 is open to the casting roll surface 7 and is connected to a suction line 25 and a suction pump, not shown.
• the suction chamber 24 is formed in a simple manner by a U-profile open to the casting roll surface, which extends parallel to the roll axis 3, 4 at a short distance from the casting roll surface over the entire length of the casting roll.
• the gap between the suction chamber 24 and the casting roll surface 7 is covered with seals attached to the U-profile and the casting roll surface 7 touching seals 27, which are preferably designed as brush or rubber lip seals.
• the suction device 23 is formed by a plurality of suction chambers 24 arranged side by side in the circumferential direction of the casting rolls 1, 2, and each suction chamber is via an associated suction line 25, each with a stage of a multi-stage suction pump, not shown connected.
• This designed as a serial multi-chamber sealing device 23 makes it possible to operate the introduced air in several suction stages with the chamber pressure gradually decreasing in the direction of casting.
• the pressure in the last suction chamber 31 in the direction of casting rotation is set to a value below 50 mbar, preferably below 10 mbar, in order to achieve optimal air suction.
• an inert gas supply 28 is additionally between the suction chamber 24 and the cover 13 arranged, which is formed by a vacuum chamber 29 and has an opening 32 directed towards the casting roll surface. In addition, it is connected to a supply line 30 for inert gas.
• the vacuum chamber 29 is designed in the same way as the suction chamber 24, and both are combined in one structural unit in order to prevent entry of false air. For the same reason, the vacuum chamber 29 is connected to the cover 13 in an airtight manner.
• the vacuum chamber 29 is formed with an outlet opening directed against the casting roller surface 7, the vacuum chamber being combined with the serial multi-chamber system of the sealing device 23 to form a structural unit and being sealed against air access.
• Inert gas is introduced into the vacuum chamber 29 in order to build up a flow boundary layer of inert gas on the casting roll surface 7, which is introduced into the casting chamber 9 instead of the air through the gap 18 between the casting rolls 1, 2 and the covering hood 13.
• the pressure in the vacuum chamber 29 is set at least 10 mbar, preferably more than 200 mbar, above the pressure of the upstream suction device 23.
• FIG. 3 shows an embodiment in which a plurality of vacuum chambers 29, which are connected to a common inert gas supply 28, are arranged within a suction chamber 24, connected to a suction line 25, for the fresh air suction.
• the inert gas pressure is set to a value above atmospheric pressure.
• Last residues of the atmospheric oxygen adhering to the casting roll surface 7 in the boundary layer can be removed with the inert gas purging if the inert gas is blown directly against the casting roll surface 7 is, for which the flow velocity is set to at least 0.5 m / s, preferably to more than 2 m / s. Flow velocities of more than 10 m / s bring no additional effect.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Continuous Casting (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
• Coupling Device And Connection With Printed Circuit (AREA)
• Manufacture Of Switches (AREA)
• Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
• Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)
• Spark Plugs (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=11404759

Family Applications (1)

Country Status (17)

Families Citing this family (5)

Family Cites Families (17)

• 1997
  • 1997-02-14 IT IT97RM000082A patent/IT1290932B1/it active IP Right Grant
• 1998
  • 1998-02-12 KR KR10-1999-7006578A patent/KR100525035B1/ko not_active Expired - Fee Related
  • 1998-02-12 BR BR9807225-0A patent/BR9807225A/pt not_active IP Right Cessation
  • 1998-02-12 ES ES98910649T patent/ES2160406T3/es not_active Expired - Lifetime
  • 1998-02-12 DE DE59800886T patent/DE59800886D1/de not_active Expired - Fee Related
  • 1998-02-12 ID IDW990629A patent/ID22429A/id unknown
  • 1998-02-12 US US09/367,434 patent/US6415849B1/en not_active Expired - Fee Related
  • 1998-02-12 RU RU99119593/02A patent/RU2199416C2/ru not_active IP Right Cessation
  • 1998-02-12 CA CA002281703A patent/CA2281703A1/fr not_active Abandoned
  • 1998-02-12 CN CN98802525A patent/CN1072056C/zh not_active Expired - Fee Related
  • 1998-02-12 AU AU64963/98A patent/AU744243B2/en not_active Ceased
  • 1998-02-12 EP EP98910649A patent/EP0961665B1/fr not_active Expired - Lifetime
  • 1998-02-12 WO PCT/EP1998/000788 patent/WO1998035773A1/fr not_active Ceased
  • 1998-02-12 PL PL98335252A patent/PL335252A1/xx unknown
  • 1998-02-12 AT AT98910649T patent/ATE202304T1/de not_active IP Right Cessation
  • 1998-02-12 JP JP53534498A patent/JP2001512371A/ja active Pending
  • 1998-12-02 UA UA99084539A patent/UA48296C2/uk unknown

Non-Patent Citations (1)

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