EP0092844B1 - Method and apparatus for feeding and continuously casting molten metal with inert gas applied to the moving mold surfaces and to the entering metal - Google Patents

Method and apparatus for feeding and continuously casting molten metal with inert gas applied to the moving mold surfaces and to the entering metal Download PDF

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Publication number
EP0092844B1
EP0092844B1 EP83104073A EP83104073A EP0092844B1 EP 0092844 B1 EP0092844 B1 EP 0092844B1 EP 83104073 A EP83104073 A EP 83104073A EP 83104073 A EP83104073 A EP 83104073A EP 0092844 B1 EP0092844 B1 EP 0092844B1
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European Patent Office
Prior art keywords
feeding
metal
inert gas
moving mold
gas
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EP83104073A
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German (de)
English (en)
French (fr)
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EP0092844A1 (en
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Robert William Hazelett
Charles J. Petry
Stanley W. Platek
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Hazelett Strip Casting Corp
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Hazelett Strip Casting Corp
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Priority to AT83104073T priority Critical patent/ATE25210T1/de
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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
    • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
    • 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

Definitions

  • This invention relates to methods and apparatus for continuously casting molten metal according to the first part of claim 1, 2 and 16, respectively.
  • the invention herein is described as embodied in the structure and operation of casting machines in which the molten metal is fed through a semi-sealing nosepiece into the moving mold or casting region located between opposed portions of two moving water or liquid- cooled molds having surfaces defining the mold region.
  • the moving molds in the illustrative examples shown are flexible bands or belts which act as cooling surfaces and enclose or confine the molten metal introduced into the moving mold between them, and they simultaneously move the molten metal progressively toward solidification into forms or products, such as strip, sheet, slab, plates, bars, or billets, hereinafter called the "cast product" or "product being cast”.
  • critical factors for casting metal of acceptable quality and having appropriate surface qualities and surface characteristics for commercial applications are the avoidance of rapid changes in the velocity of the molten metal being introduced, and the avoidance of turbulence in the molten metal, the limiting of exposure of the metal to a reactive atmosphere or other reactive agents, and the provision of favorable interaction between the moving mold surfaces and the metal being confined by these surfaces.
  • Molten metal handling and distribution equipment which conveys the molten metal to be cast from the melting or holding furnace to the mold region of the casting machine, is generally designed to avoid restrictions and to limit exposure of the molten metal to an uncontrolled atmosphere, usually accomplished by under-pouring at each transfer.
  • the molten metal is not poured over an open lip, but instead is drawn well below the surface of the vessel, so as to leave behind surface oxides and most foreign matter.
  • Such under-pouring technique further transfers or introduces the molten metal into the next vessel under the surface of the metal therein, in such a way as to minimize agitation and to avoid contact with atmospheric or oxygen-bearing agents.
  • Oxidation problems within launders, troughs, and tundishes have been generally solved by under-pouring, together with the use of reducing atmospheres applied to the surface of the molten metal.
  • reducing atmospheres are obtained through flames of burning oil or gas which are rendered deficient in the oxygen supplied to them.
  • a protective oxide film will remain quietly upon the surface of an open vessel, when designed so as to minimize agitation, and in this case reducing atmospheres are not required in the preliminary stages of aluminum transfer with under-pouring.
  • Entrapment of oxides, or other impurities is less apt to occur in the conventional vertical continuous casting processes, which use a rigid mold that is open at the top and bottom. In these vertical casting processes the pouring into the mold is generally accomplished by under-pouring, and at a relatively slow rate. Such oxides, and other impurities as do form, have time to float to the top, and thus they are prone to remain in the top oxide layer which forms there or to become frozen in the center or core region of the ingot of relatively large cross-sectional area being cast. In this case of vertical casting of large cross-sectional products, the entrapped oxides or other impurities are not likely to be detrimental to, nor render unacceptable, the products being cast.
  • the US ⁇ A ⁇ 4,062,397 forming the preambles of claim 1, 2 and 16, relates to a shroud for enclosing a stream of molten metal in an inert atmosphere as the metal is poured from a tundish to a chill mold.
  • This so called continuous casting apparatus uses gravity in a vertical free fall feed into the mold unit.
  • the stationary mold unit includes cavities in the form of elongated rectangular blocks of water cooled molds. The inert gas is feeded into the shroud surrounding the metal stream and by additional conductors directly into the mold cavity.
  • the techniques of under-pouring for the introduction of the molten metal into the moving mold region of continuous casting machine is usually not practical or feasible, as there is insufficient vertical clearance between the mold surfaces.
  • the molten metal is usually introduced through a semi-sealing nosepiece.
  • this nosepiece must be spaced slightly away from the moving mold surfaces near the entrance to the mold region in order to compensate for the inevitable variables and variations in the entrance to the continuously moving mold.
  • Such spacing from the continuously moving mold surfaces is also needed to allow for the dimensional tolerances involved in the forming and shaping of the refractory material having suitable physical, chemical and thermal properties for the demanding service of handling molten metal.
  • the refractories suitable for this demanding purpose are difficult to shape and maintain within close and consistent operating tolerances.
  • the fit between the nosepiece for feeding molten metal and the continuously moving mold surfaces must be relatively loose, with an initial gas of 0.010 inch (0.25 mm) being customary for a new nosepiece.
  • this gap through wear, will- tend to widen, especially on the top of the nosepiece.
  • the periodic leakage of most molten metals around the sealing surfaces of the nosepiece is inevitable if the operator of the moving mold attempts to keep the_mold region continuously filled up against the nosepiece with molten metal. In other words, it is just usually not practicable to attempt to keep the molten metal in the mold region full up against the nosepiece.
  • a gap of about 0.020 inch (0.5 mm) around the nosepiece will generally leak any molten metal of low surface tension, and such metal will readily, quickly solidify or freeze untimely into 'fins", causing an undesirable jamming action against the nosepiece, resulting in destruction of the nosepiece.
  • Molten aluminum and aluminum alloys in particular are highly reactive. They can combine with other metals, gases and refractories.
  • aluminum alloys are susceptible to random reaction with or are affected by atmospheric oxygen, water vapor, and trace atmospheric gas pollutants.
  • random atmospheric contact results in reactions which, in turn, cause oxide spots or streaks on the cast surface, and will also reduce the fluidity of such alloys in a molten state.
  • Relatively thin sections as used herein is intended to include the range from 1/4 inch (6 mm) to 2 inches (51 mm), the preferred range between 1/4 inch (6 mm) to 1-1/2 inches (38 mm).
  • molten metal is introduced into the upstream or entrance end of the continuously moving mold region through a semi-sealing nosepiece accurately mating or fitting with the moving mold surfaces and having clearance gaps from the moving mold surfaces of less than 0.050 of an inch (1.27 mm) while inert gas is applied to the moving mold surfaces and to the entering metal for the protection or shrouding of the molten metal surface within the mold cavity from oxygen and other detrimental atmospheric gases.
  • An advantageous shrouding of in-feeding molten metal, controlled cavity in the upper end of the mold region and of the moving mold surfaces is accomplished by means of inert gas injected into the mold through the semi-sealing nosepiece, or directed at the mold cavity and passing through the clearance gaps around the nosepiece.
  • inert gas is further circulated for cleansing the moving mold surfaces of undesired accompanying or adhering gases associated with the mold surfaces as the mold surfaces approach the nosepiece before entering. the mold region.
  • the invention in certain of its aspects, as embedded in the illustrative methods and apparatus, comprises in-feeding molten metal through at least one passage in a nosepiece of refractory material inserted toward the upstream end of a continuously moving mold region and having clearance gaps of less than 0.050 of an inch (1.27 mm) from the continuously moving mold surface, securing the nosepiece with rigid support structure clamps above and below, supplying inert gas through at least one passage in at least one of the said clamps, to quietly introduce said inert gas into at least one of the narrow clearance gaps around the inserted nosepiece, for shrouding the entering molten metal and the controlled cavity in the upper end of the moving mold region.
  • the invention in other of its aspects as embodied in the illustrative methods and apparatus comprises in-feeding molten metal through at least one passage in a nosepiece of refractory material inserted toward the entrance of the continuously moving mold region and mating with the continuously moving mold surfaces with clearance gaps therefrom of less than 0.050 of an inch (1.27 mm), introducing the molten metal to be cast through at least one passage in at least one part of the inserted nosepiece; simultaneously injecting inert gas directly through at least one additional passage in at least one part of said nosepiece for introducing the inert gas directly into the controlled cavity in the entrance end of the mold region for enhancing the qualities and characteristics of the metal product being continuously cast.
  • the invention in additional aspects comprises those features or aspects described in the above two paragraphs including feeding inert gas through at least one passage in at least one of the nosepiece support structures while simultaneously also feeding inert gas through at least one passage in the nosepiece itself.
  • the invention comprises placing a shield member or structural member relatively near to at least one of the moving mold surfaces where it is travelling toward the entrance to the moving mold region and applying inert gas to the channel thus defined close to this moving mold surface for causing the moving mold surface to become bathed in the inert gas for carrying or propelling the inert gas through the clearance gap by the nosepiece and into the entrance to the moving mold region.
  • the present invention comprises placing a shield member or structural member relatively near to at least one of the moving mold surfaces where it is travelling toward the entrance to the moving mold region for casting a relatively thin metal section and applying inert gas to the channel thus defined close to this moving mold surface for cleansing the mold surface for removing therefrom atmospheric gases and/or contaminating pollution gases and/ or water vapor which may be carried by or adherent to the moving mold surface for enhancing the qualities and characteristics of the continuously cast metal product of relatively thin section being cast.
  • passageways and/or chambers associated with support structure for the metal feeding nosepiece for applying this gas forwardly against the moving mold surface as they are travelling in converging relationship toward the entrance of the moving mold for casting a relatively thin metal section.
  • passageways and/or chambers may include outlets directed laterally toward the respective moving edge dams employed in the twin-belt casters for bathing, enveloping and cleansing these moving edge dams with inert gas as they are approaching the moving mold.
  • inert gas can be introduced directly into any cavity existing in the upstream portion of a moving mold casting a relatively thin metal section in generally horizontal or downwardly inclined orientation for establishing an inert gas pressure in such cavity slightly exceeding atmospheric pressure for shrouding the cavity itself and for causing the inert gas to flow outwardly in back-flushing, cleansing, bathing relationship through clearance gaps between the moving mold surfaces and the inserted metal-feeding nosepiece.
  • the inert gas is introduced through at least one passage in the refractory material of the nosepiece itself while molten metal is in-feeding through at least one other passage in the nosepiece.
  • the output of the gas passage may be elevated above the center-line of the nosepiece for assuring that the inert gas is entering any cavity in the upstream portion of the moving mold above the level of the molten metal therein.
  • the inertgas can be introduced indirectly into any cavity existing in the upstream portion of a moving mold casting a relatively thin metal section in generally horizontal or downwardly inclined orientation by applying the inert gas to at least one of the moving mold surfaces while said surface is travelling toward the entrance to the moving mold.
  • the inert gas is introduced gently through passages and/or chambers in the support structure for the refractory nosepiece feeding the molten metal, and at least one shield member may be conformed in configuration relatively near to the moving mold surface for achieving effective application of the inert gas to the moving mold surface and for causing a diffusing, enveloping, cleansing action of the inert gas against the moving mold surface.
  • a further aspect of the present invention is those installations wherein inert gas is indirectly introduced into the mold through clearance gaps around the nosepiece will now be described.
  • This aspect is the simultaneous, advantageous use of two kinds, two densities, of inert gas at the same time.
  • an inert gas which is heavier than air is applied above the nosepiece; such gas will tend to lie down upon the nosepiece and its upper support structure rather than to dissipate.
  • an inert gas which is lighter than air may be applied below the nosepiece; such gas will tend to rise and to lie up against the bottom of the nosepiece and its lower support structure rather than to dissipate.
  • a suitable heavier-than-air gas for top use is argon, which is about 35 percent heavier than air.
  • a suitable lighter-than-air gas for bottom use is nitrogen, which is about 3 percent lighter than air.
  • molten metal 1 is supplied through in-feed apparatus which may be a pouring box, ladle or launder 2, and flows down through a pouring spout 3 in under-pouring relationship into a tundish 4, which is lined with a suitable refractory material 31.
  • in-feed apparatus which may be a pouring box, ladle or launder 2
  • a pouring spout 3 in under-pouring relationship into a tundish 4
  • tundish 4 which is lined with a suitable refractory material 31.
  • the tundish is shown slightly withdrawn in Fig. 1 from the entrance to the moving mold.
  • the rate of flow from the launder which is shown at 2 to the tundish 4 is controlled by a tapered stopper (not shown), mounted on the lower end of a control rod 5.
  • the molten metal 1 is fed through a nozzle or nosepiece 7 of refractory material, or through tubes 21 (Fig. 7) into the entrance E of the moving mold or casting region C.
  • This entrance E is at the upstream end of the casting region C, which is formed between spaced and substantially parallel surfaces of upper and lower endless flexible casting belts 9 and 10, respectively.
  • the casting belts are normally made of low-carbon, cold-rolled strip steel of uniform properties, and welded by TIG welding. They are normally grit-blasted for roughening the surface which will face the molten metal; followed by roller-levelling and coating.
  • the casting belts 9 and 10 are supported on and driven by respective upper-and lower carriages, generally indicated at U and L. Both carriages are mounted on a machine frame 11. Each carriage includes two main rolls or pulleys which directly support, drive, and steer the casting belts. These pulleys includes upper and lower input or upstream pulleys 12 and 13, and upper and lower output or downstream pulleys 14 and 5, respectively.
  • the casting belts 9 and 10 are guided by multiple finned backup rollers 16 (Fig. 2), so that the opposed belt casting surfaces are maintained in a preselected relationship throughout the length of the casting region C.
  • These finned backup rollers 16 may be of the type shown and described in U.S. Patent No. 3,167,830.
  • the side dams 17 (only one is seen in Fig. 2) are guided at the input or upstream end of the casting machine by guide members 35, shown in part, which are mounted on the lower carriage L, for example, such as are shown in said U.S. patent, or in U.S. Patent No. 4,150,711.
  • the two casting belts 9 and 10 are driven at the same linear speed by a driving mechanism 18 which, for example, is such as described in said Patent No. 3,167,830.
  • a driving mechanism 18 which, for example, is such as described in said Patent No. 3,167,830.
  • the upper and lower carriages U and L are downwardly inclined in the downstream direction, so that the moving mold casting region C between the casting belts is inclined at an angle A with respect to the horizontal.
  • This downward inclination A facilitates flow of molten metal into the entrance E of the casting region C.
  • This inclination angle A is usually less than 20°, and it can be adjusted by a jack mechanism 50.
  • the presently preferred inclination for aluminum and its alloys is in the range from 6° to 9°.
  • Intense heat flux is withdrawn through each casting belt by means of a high-velocity moving layer of liquid coolant, applied from nozzle headers 6 and travelling along the reverse, cooled surfaces of the upper and lower belts 9 and 10, respectively.
  • the liquid coolant is applied at high velocity, and the fast-flowing layer may be maintained in a manner as shown in said Patent No. 3,167,830 and in Patent No. 3,041,686.
  • the presently preferred coolant is water with rust inhibitors at a temperature in the range from 70°F (21°C) to 90°F (32°C).
  • the cast product P After the cast product P has solidified at least on all of its external surfaces, and has been fed out of the casting machine, it is conveyed and guided away by a roller conveyor (not shown).
  • the nosepiece may be made of marinite or other suitable refractory material.
  • This nosepiece 7 is made of one integral piece of refractory material as shown in Figs. 5 and 6. Alternatively, this nosepiece 7 may be assembled from a plurality of integral pieces of refractory material.
  • nosepiece as used throughout may refer to a single integral member or to an assembly of a plurality of integral pieces.
  • the refractory nosepiece 7 includes at least one metal feeding passage 20.
  • These metal feeding passages 20 have a rectangular cross section. They are relatively wide with shallow vertical dimension as is appropriate for casting relativeiy thin metal sections.
  • the downstream ends of these metal feeding passages 20 are shown flared out gradually laterally in the downstream direction as indicated at 41 (Figs. 5 and 6).
  • the upper and lower supporting structures 25 and 26 for clamping the refractory nosepiece 7 between them are generally similar in construction, except that the lower one is inverted in configuration.
  • These supporting structures 25 and 26 are rigid, for example, being made of steel.
  • Fig. 4 is shown enlarged the upper support clamp structure 25.
  • This structure includes a rigid base plate 28 wY ose clamping surface 42 includes shallow transversely extending lands 43 and grooves 44 for securing a firm clamping engagement with the refractory nosepiece 7.
  • the assembly of this base plate 28 and rear wall 45 is stiffened by a diagonal plate 33 welded at 48 and 49, respectively, to the base plate and rear wall.
  • the slope of this diagonal plate 33 generally conforms to the configuration of the nearby upper casting belt 9 where this belt is curved and travelling (arrow 51) around the upper input pulley roll 12.
  • this diagonal plate 33 is sloped to be generally parallel to an imaginary plane tangent to the nearest region of the cylindrically curved belt 9.
  • a triangular side wall 53 (Fig. 4) secured in gas-tight relationship to the baseplate, rear wall and diagonal plate 33 and a corresponding triangular side wall (not seen) at the other side of the support clamp structure 25 thereby forming a "lean-to" plenum chamber 54.
  • a portion of the structure 25 is shown cut away to reveal clearly- this lean-to chamber 54, and there is a similar "lean-to" plenum chamber 54 in the lower clamp structure 26.
  • Sockets or mounting holes 55 are provided in this clamp structure 25 for attachment to mounting brackets 56 (Fig. 3) which are mounted on upstream end portions 57 of the main frame members of the lower carriage L.
  • the tundish 4 is shown supported by a bar 58 extending from the bracket 56, and other support mounting means 65 for the tundish may be provided.
  • the forward (downstream) edge or lip of the base plate 28 is chamfered at 59 at a slope less steep than the diagonal plate 33. As seen in Fig. 3, this sloped lip 59 is generally parallel with an imaginary plane tangent to the nearby curved moving mold surface 9.
  • Fig. 3 shows the molten metal exiting at 60 from the passage 20 in the nosepiece 7 and entering the entrance region E of the moving mold casting region C.
  • a resultant gas space or cavity 8 thereby exists in the entrance region E above the level of the molten metal in the moving mold region C adjacent to the downstream end of the nosepiece 7.
  • the nosepiece 7 is provided with at least one longitudinally extending gas feed passage 19 (Fig. 6) running along side of the metal feeding passages 20.
  • This gas feed passage 19 is located in the center portion 40 of the refractory material in the nosepiece.
  • This gas feed passage 19 is located at a level above the center-line of the nosepiece 7 and its outlet 61 is near the upper edge of the downstream end or terminus 62 of the nosepiece. The way in which the inert gas is fed down into the vertical inlet port 63 connecting with the gas feed passage 19 will be explained later.
  • the gas flow is generally above the level of the molten metal exiting 60 (Fig. 3) from the in-feed passages 20.
  • the inert gas enters directly into the cavity 8 for maintaining this cavity charged with inert gas at a pressure slightly above atmospheric pressure.
  • the elevated position of the gas feed outlet 61 will usually place it above the metal, so that it will usually remain unblocked by the molten metal in the entrance E and therefore, be in continuous communication with the controlled gas cavity 8.
  • the gas feed outlet 61 is shown connected with a horizontally extending transverse narrow groove or slot 61-1 cut into the terminus 62 of the refractory nosepiece 7 for aiding in distributing the inert gas directly into the controlled gas cavity 8 at low velocity with minimum resulting agitation or turbulence of the molten metal.
  • the cavity 8 thus remains controlled by continuous in-feed of inert gas through one or more passages 19 at a pressure slightly above atmospher4c pressure. Invasion into the cavity 8 of undesirable gases, particularly oxygen and water vapor (and also atmospheric polluting gases, such as sulphur dioxide and carbonic acid gas) is prevented by this insert gas being continuously charged into this cavity.
  • the inert gas shrouds this cavity 8 and purges and thereafter excludes the undesirable gases from the entrance region E.
  • a constant flow of inert gas is maintained through the gas feed passage 19 during casting, maintaining the cavity 8 full of inert gas slightly above atmospheric pressure.
  • Some of this constant flow of inert gas exits in the upstream direction through the aforementioned narrow clearance gaps at 22.
  • These clearance gaps 22 are less than 0.050 of an inch (1.27 mm) and are usually in the range of 0.010 of an inch (0.25 mm) to 0.020 of an inch (0.5 mm).
  • the inert gas exiting through these clearance gaps 22 around the nosepiece 7 advantageously scours, cleans, and displaces atmospheric gases, including water vapor, off from the incoming mold surfaces 9 and 10 and flushes the gases away from the entrance region E.
  • the above-described close-flowing, displacing, enveloping, cleansing action on the moving mold surfaces is enhanced and extended over a wide area of the moving mold surfaces 9 and 10 as they converge 51, 52 toward the entrance region E by forming a narrow channel 66 for confining the exiting inert gas close to these moving mold surfaces 9 and 10 by means of curved shield members 34 (Fig. 3) positioned between the diagonal plates 33 and the moving mold surfaces.
  • the shield members 34 are cylindrically curved for nesting close to the respective curved moving mold surfaces 9 and 10, being spaced less than 1/ 4 inch (6 mm) and preferably at close proximity within. 1/8 inch (3 mm) from these moving surfaces.
  • the forward (downstream) edge of the curved shield member 34 is welded along the crest 64 (Fig. 4) of the base plate 28 near the upstream border of the chamfered lip 59.
  • the inert gas exists at 36 (Fig. 3) from the narrow channel 66 between the shield 34 and the closely proximate moving mold surface 9 or 10 after flowing through this narrow channel in a direction counter to the motion 51 or 52 of the moving mold surface in close-flowing, displacing, cleansing relationship therewith.
  • the use of the shield members 34 advantageously reduces the consumption of inert gas and also increases the time duration of exposure of the moving mold surfaces 9, 10 to the inert gas for displacing, cleansing of atmospheric gases therefrom.
  • a loose, flexible packing material 23 may be placed in this narrow channel 66.
  • a suitable loose, flexible packing for example, is fiberglass insulation or "Kaowool" ceramic insulation. This loose packing may be allowed only lightly to contact the moving mold surfaces 9, 10. It may be placed in the channel 66 and/or adjacent to the forward edge of the sloping lip 59 against the nosepiece 7, as shown at 23. This Loose packing 23 may be used only with the "direct" in-feeding of inert gas into the cavity 8 through passages 19 (Fig. 6) in the nosepiece 7.
  • the adsorbed and/or entrained atmospheric gases would be carried or conveyed continuously into the moving mold with consequent adverse effects upon the metal product P being cast, except for the advantageous scouring, diffusing, and displacing action upon the moving mold surfaces 9, 10 caused to occur by the inert gas as described above.
  • some of the inert gas exits from the pressurized controlled gas cavity 8 by flowing out laterally to each side past the respective moving edge dams 17, thereby scouring and displacing atmospheric gases off from these edge dams and excluding such gases from invasion into the entrance region 8.
  • This inert gas is often nitrogen, but it may be argon, carbon dioxide, or other gas which is appropriately inert and non-reactive in relation to the particular metal or alloy 1 being cast.
  • the inert gas which can be used to advantage when casting aluminum and aluminum alloys is pre-purified nitrogen that has been water-pumped, i.e., pumped with water sealing in the compressors and known as "dry” nitrogen, as distinct from oil- pumped nitrogen.
  • This "dry-pumped” nitrogen is ordinarily sold to welders as shielding gas.
  • a typical specification (for such nitrogen shielding gas) calls for less than two parts per million of oxygen, and less than six parts per million of water.
  • an advantageous "indirect” in-feeding of the inert gas may also be employed.
  • the inert gas G enters a supply port 68 in the triangular end wall 53 for feeding the inert gas G into the lean-to plenum supply chamber 54.
  • This supply port 68 is threaded for a connection fitting to a gas feed pipeline or flexible conduit (not shown).
  • each longitudinally drilled passage 27-2 is closed by a plug 67.
  • Each end of the transversely drilled header passage 27-3 is closed by a plug 67.
  • an orifice 24-2 is drilled in each of the latter two plugs 67.
  • Inert gas issuing through the orifices 24 in the sloping lip surface 59 is advantageously applied to the moving mold surfaces 9 and 10 at close range for gently, noiselessly covering, blanketing, enveloping and cleansing them. If the direct in-feed gas passages 19 are omitted from the nosepiece 7, as shown in Fig. 5, then the motion 51,52 (Fig. 3) of the mold surface 9,10 carries and propels some of this inert gas into the cavity 8.
  • An advantageous arrangement is to drill the orifices 24 in a horizontal row spaced one inch apart (25 mm) in a center-to-center distance and each having a relatively small diameter, for example, of 0.062 of an inch (1.6 mm).
  • the flow rate that has been successfully used is 10 cubic feet (0.28 cubic meter) per hour for a cast width of 14 inches (355 mm), and a cast thickness up to 1 inch (25 mm).
  • This ten cubic feet per hour is the volume of inert gas at atmospheric pressure and at room temperature.
  • the corresponding calculated velocity of noiseless ejection of inert gas from the orifices 24 is approximately 5 feet per second (1.5. meters per second).
  • Laminar flow is by definition non-turbulent flow, which non-turbulence is a necessity for avoiding the entrainment of air.
  • the turbulence and disturbance noise associated with too high a flow rate will entrain air; such air entrainment being undesirable.
  • these orifices can be terminated in a transverse slot or groove 24-1 milled into the sloping surface 59.
  • the inert gas As the inert gas is expelled from the multiple orifices 24, it slows down and thus evidently creates a continuous zone or "ridge" of minute pressure in the cusp region between the moving mold stream 9 or 10, the sloping lip 59 and the forward (downstream) end of the nosepiece. This slowing down and creating of the pressure ridge is aided and abetted by culminating the orifices 24 in the transverse slot or grooves 24-1. Some of the gas from this pressure ridge flows through the clearance gap 22 into the controlled gas cavity 8. The remainder of the inert gas from this pressure - ridge flows upstream; that is, flows out through the channel 66 in the close-flowing, displacing, cleansing action, as described above, exiting at 36.
  • This "indirect” method of applying the inert gas quietly; that is, noiselessly with no audible disturbance into the entrance E to the moving mold, by forming the pressure ridge in the cusp region near the nosepiece, as described above, is the preferred method for producing aluminum cast product P and aluminum alloy cast product P and especially for producing aluminum alloy cast products P containing magnesium, even relatively high percentage of magnesium, that are attractively free from undesirable and troublesome surface oxide and have acceptable qualities and characteristics on the surfaces and also in the interior.
  • the inert gas is fed into the inlet port 63 leading to the passage 19 by drilling a passage 70 leading from the slightly pressurized plenum chamber 54 through the base plate 28 and through one of the lands 43 in alignment with and in communication with the inlet port 63.
  • additional outlet orifices 72 may be drilled through the diagonal plate 33 into the pressurized lean-to plenum chamber 54.
  • the moving mold surfaces 9 and 10 are covered with appropriate coating, for example, coatings of silicone oil type or an alkyl oil type, which may be used with or without admixtures of graphite.
  • appropriate coating for example, coatings of silicone oil type or an alkyl oil type, which may be used with or without admixtures of graphite.
  • tubes 21 are made of high temperature resistant refractory material, for example, fused silicon dioxide (quartz), titanium dioxide, aluminum oxide, or high temperature refractory nitride materials, all of which are commercially available in the form of tubes.
  • the tubes 21 are embedded in parallel holes in the accurately machined nosepiece 7.
  • a plurality of parallel in-feed gas passages 63 and 19 analogous to the arrangement shown in Fig. 6 are drilled in the nosepiece 7 for the injection of inert gas G directly into the controlled gas cavity 8 (Fig. 8).
  • This inert gas comes from the pressurized lean-to plenum chamber 54 (see also Fig. 4) through appropriately located supply passages 70 communicating with the respective vertical passages 63.
  • the clearance gaps adjacent to the downstream end of the nosepiece 7 are shown at 22.
  • a loose flexible packing seal 23 is placed above and below the nosepiece 7 adjacent to the downstream edge of the lip 59 (Fig. 4) of the baseplate 28 of the support clamp structures 25, 26. This packing 23 may be allowed to contact the moving mold surfaces 9 and 10.
  • inert gas may be fed into the narrow channels between the diagonal plates 33 (Fig. 8) and the moving mold surfaces 9, 10 by employing outlet orifices 72 (Fig. 4) in these diagonal plates.
  • Fig. 8 does not show the curved shield members 34 (Figs. 3 and 9), it is to be understood that such shields may be employed with the multi-tube 21 metal feed shown in Figs. 7 and 8.
  • indirect feeding of inert gas through passages 27-1, 27-2, 27-3, 24 and 21-1 in the clamp structures 25 and 26 may be employed.
  • FIG. 9 An alternative method of feeding the molten metal, called "open-pool” feeding is shown in Fig. 9. While open-pool feeding involves no closely fitting nosepiece 7, its use is at times appropriate, particularly when casting thicker metal sections above 1-1/2 inches (38 mm) in thickness.
  • the inert gas is supplied through the supply ports 68 into "lean-to" chambers 54' of funnel-like configuration. These lead-to-funnel chambers 54' are defined by the curved shield 34, the base plate 28 and rear wall 45 of the supporting clamp structure 25 or 26 and by a shield-supporting wall plate 74 welded between the rear wall 45 and the shield 34.
  • the inert gas flows downstream from the funnel chamber 54' through the exit 38 adjacent to the downstream edge of the curved shield 34.
  • this inert gas flows in shrouding relationship into the entrance region E of the moving casting mold C. Some of this inert gas returns upstream through the narrow channels 66 in cleansing relationship with the moving mold surfaces and then exiting from these channels at 36.
  • the present invention improves the surface qualities and characteristics of continuously cast metal product P of relatively thin section when cast in approximately horizontal or downwardly inclined orientation mode, particularly of aluminum and its alloys, including high magnesium alloys thereof, and also provides improvement in the internal qualities and characteristics of such continuously cast metal products.
  • This invention also improves the qualities of thicker continuously cast metal product P when cast in the horizontal mode or downwardly inclined mode.
  • downwardly inclined means at an angle less than 45° with respect to the horizontal and usually less than approximately 20°.
  • Examples of aluminum alloys which can be continuously cast with ' advantage using the present invention are:
  • AA 3105 at casting speeds up to at least 1,000 pounds per hour per inch of width of the moving mold.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)
  • Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
  • Manufacture Of Alloys Or Alloy Compounds (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Processing Of Solid Wastes (AREA)
  • Coating With Molten Metal (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Nonmetallic Welding Materials (AREA)
  • Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
EP83104073A 1982-04-28 1983-04-26 Method and apparatus for feeding and continuously casting molten metal with inert gas applied to the moving mold surfaces and to the entering metal Expired EP0092844B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT83104073T ATE25210T1 (de) 1982-04-28 1983-04-26 Verfahren und einrichtung fuer das beschicken und kontinuierliche giessen von geschmolzenem metall mit inertem gas, angewandt auf bewegende formoberflaechen und auf das eintretende metall.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US37245982A 1982-04-28 1982-04-28
US372459 1995-01-13

Publications (2)

Publication Number Publication Date
EP0092844A1 EP0092844A1 (en) 1983-11-02
EP0092844B1 true EP0092844B1 (en) 1987-01-28

Family

ID=23468206

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83104073A Expired EP0092844B1 (en) 1982-04-28 1983-04-26 Method and apparatus for feeding and continuously casting molten metal with inert gas applied to the moving mold surfaces and to the entering metal

Country Status (10)

Country Link
EP (1) EP0092844B1 (enrdf_load_stackoverflow)
JP (1) JPS5942164A (enrdf_load_stackoverflow)
KR (1) KR910006550B1 (enrdf_load_stackoverflow)
AT (1) ATE25210T1 (enrdf_load_stackoverflow)
AU (1) AU561611B2 (enrdf_load_stackoverflow)
BR (1) BR8302178A (enrdf_load_stackoverflow)
CA (1) CA1208412A (enrdf_load_stackoverflow)
DE (1) DE3369474D1 (enrdf_load_stackoverflow)
NO (1) NO161246C (enrdf_load_stackoverflow)
ZA (1) ZA832935B (enrdf_load_stackoverflow)

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4487157A (en) * 1983-11-07 1984-12-11 Hazelett Strip-Casting Corporation Machine for producing insulative and protective coatings on endless flexible metallic belts of continuous casting machines
CA1235565A (en) * 1983-11-07 1988-04-26 Hazelett Strip Casting Corp Matrix coating flexible casting belts, method and apparatus for making matrix coatings
CA1252754A (en) * 1984-04-09 1989-04-18 Daniel K. Ai Roll caster apparatus
AU578967B2 (en) * 1984-09-13 1988-11-10 Allegheny Ludlum Steel Corp. Method and apparatus for direct casting of crystalline strip in non-oxadizing atmosphere
KR940008621B1 (ko) * 1985-06-27 1994-09-24 가와사키세이데쓰 가부시키가이샤 엔드레스 스트립의 주조방법 및 그 장치
DE3623937A1 (de) * 1986-07-16 1988-01-21 Didier Werke Ag Feuerfeste kanalverbindung zum ueberfuehren von stahlschmelze in giessrad-stranggiessmaschinen
EP0258469A1 (de) * 1986-08-29 1988-03-09 Fried. Krupp Gesellschaft mit beschränkter Haftung Vorrichtung zum Bandgiessen von Stahl in einer Doppelbandgiesskokille
US4972900A (en) * 1989-10-24 1990-11-27 Hazelett Strip-Casting Corporation Permeable nozzle method and apparatus for closed feeding of molten metal into twin-belt continuous casting machines
FR2654657B1 (fr) * 1989-11-22 1992-03-20 Siderurgie Fse Inst Rech Dispositif de coulee continue de bandes minces de metal entre deux cylindres.
JP3035507U (ja) * 1996-09-06 1997-03-28 株式会社横田製作所 複測式軸心度計測装置
DE102009012984B4 (de) * 2009-03-12 2013-05-02 Salzgitter Flachstahl Gmbh Gießdüse für eine horizontale Bandgießanlage
CN102554157A (zh) * 2010-12-21 2012-07-11 湖南晟通科技集团有限公司 将惰性气体通入铸嘴的方法及铸嘴夹具

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4062397A (en) * 1976-03-16 1977-12-13 Cashdollar Sr Robert E Protection against oxidation of molten metal streams in continuous casting
DE2655912C2 (de) * 1976-12-09 1983-11-03 Linde Ag, 6200 Wiesbaden Vorrichtung zum Abschirmen des Gießstrahls einer Gießanlage
FR2403852A1 (fr) * 1977-09-22 1979-04-20 Air Liquide Procede et dispositif de protection d'un jet de coulee verticale de metal fondu au moyen d'un gaz inerte liquefie
JPS58360A (ja) * 1981-04-20 1983-01-05 ヘイズレツト・ストリツプ・キヤステイング・コ−ポレ−シヨン 陽極製造用二重ベルト鋳造機より退去した後の新しく鋳造された銅製品の酸化を防止する方法および装置

Also Published As

Publication number Publication date
DE3369474D1 (en) 1987-03-05
ATE25210T1 (de) 1987-02-15
NO161246B (no) 1989-04-17
KR840004376A (ko) 1984-10-15
JPH0573505B2 (enrdf_load_stackoverflow) 1993-10-14
CA1208412A (en) 1986-07-29
ZA832935B (en) 1984-01-25
EP0092844A1 (en) 1983-11-02
AU561611B2 (en) 1987-05-14
JPS5942164A (ja) 1984-03-08
NO161246C (no) 1989-07-26
AU1402383A (en) 1983-11-03
BR8302178A (pt) 1983-12-27
NO831496L (no) 1983-10-31
KR910006550B1 (ko) 1991-08-28

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