CN112626350B - Device and method for deeply purifying aluminum-lithium alloy melt - Google Patents

Device and method for deeply purifying aluminum-lithium alloy melt Download PDF

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Publication number
CN112626350B
CN112626350B CN202011482102.3A CN202011482102A CN112626350B CN 112626350 B CN112626350 B CN 112626350B CN 202011482102 A CN202011482102 A CN 202011482102A CN 112626350 B CN112626350 B CN 112626350B
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furnace
crucible
liquid level
lithium alloy
aluminum
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CN112626350A (en
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崔建忠
王向杰
王复越
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Northeastern University China
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Northeastern University China
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/04—Refining by applying a vacuum
    • 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
    • B22D11/001—Continuous casting of metals, i.e. casting in indefinite lengths of specific alloys
    • 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
    • B22D11/116—Refining the metal
    • B22D11/117—Refining the metal by treating with gases
    • 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
    • B22D11/116—Refining the metal
    • B22D11/119—Refining the metal by filtering
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/02—Refining by liquating, filtering, centrifuging, distilling, or supersonic wave action including acoustic waves
    • C22B9/023—By filtering
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/05—Refining by treating with gases, e.g. gas flushing also refining by means of a material generating gas in situ
    • C22B9/055—Refining by treating with gases, e.g. gas flushing also refining by means of a material generating gas in situ while the metal is circulating, e.g. combined with filtration
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/02—Making non-ferrous alloys by melting
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Abstract

A device and a method for deeply purifying an aluminum-lithium alloy melt, wherein a purifying furnace in the device comprises a purifying furnace crucible, a purifying furnace body, an upper plate and a lower plate; the upper plate is provided with an upper liquid level rod, a lower liquid level rod, a purification furnace thermocouple and a vacuum tube; the lower plate is provided with a heat preservation furnace thermocouple, a heat preservation furnace liquid level rod and a measuring pipe; the heat preservation furnace comprises an upper furnace body, a heat preservation furnace crucible and a lower furnace body; the method comprises the following steps: (1) heating a purification furnace crucible and a heat preservation furnace crucible; (2) the upper liquid level rod, the lower liquid level rod and the heat preservation furnace liquid level rod respectively form a liquid level measuring circuit; (3) introducing the aluminum-lithium alloy melt into a crucible of a holding furnace; (4) vacuumizing to enable the aluminum lithium alloy melt to enter a purification furnace crucible; (5) introducing argon, mixing the argon with the aluminum-lithium alloy melt, and dehydrogenating; (6) controlling the liquid level of the aluminum lithium alloy melt; (7) the aluminum lithium alloy melt of the crucible of the holding furnace enters a crucible of a purifying furnace to form circulating purification; (8) when the hydrogen content is less than or equal to 0.10ppm, the deep purification is completed. The device and the method can reduce the hydrogen content of the aluminum lithium alloy by more than 20 times.

Description

Device and method for deeply purifying aluminum-lithium alloy melt
Technical Field
The invention belongs to the technical field of material processing, molding and manufacturing, and particularly relates to a device and a method for deeply purifying an aluminum-lithium alloy melt.
Background
The aluminum-lithium alloy has high specific strength and high specific rigidity, and is widely applied to aircrafts in the fields of aerospace and aviation. The key technology for preparing the aluminum lithium alloy is the fusion casting of the alloy; because the liquid aluminum-lithium alloy has high activity, the liquid aluminum-lithium alloy is very easy to react with water vapor in the air and react with oxygen to form oxide slag inclusion, and hydrogen is absorbed into a melt; the oxide formed on the surface of the liquid aluminum lithium alloy is loose and brittle, and air enters from micropores and cracks of the liquid aluminum lithium alloy, so that the oxidation is accelerated, and the hydrogen absorption is accelerated, therefore, the purification of the aluminum lithium alloy liquid is the basis for preparing the high-quality aluminum lithium alloy ingot blank.
Since liquid aluminum lithium alloy erodes refractory materials used in the existing industry, purification methods commonly used in the modern aluminum processing industry, such as external refining using graphite rotors, filtration using ceramic filters, and the like, cannot be used for aluminum lithium alloy; at present, the main method for purifying the aluminum lithium alloy melt is to arrange a furnace in a clean mode, vacuumize the furnace in a low vacuum mode, fill argon, blow the melt with argon and stir the melt, and the method has low purification efficiency, low hydrogen removal efficiency, particularly low slag discharge efficiency and large argon consumption; therefore, the metallurgical quality of the ingot cannot be guaranteed.
Disclosure of Invention
The invention aims to provide a device and a method for deeply purifying an aluminum-lithium alloy melt, which adopt a double-layer structure of purification and heat preservation layering, carry out deep purification on the aluminum-lithium alloy melt by controlling liquid level and temperature on line, adopting a method of uniformly blowing argon and matching with a component for preventing lithium corrosion, and greatly reduce the content of impurities and hydrogen.
The device for deeply purifying the aluminum lithium alloy melt consists of a purifying furnace A, a heat preservation furnace sealing gasket B and a heat preservation furnace C; the purification furnace A comprises a purification furnace crucible A11, a purification furnace body A10, an upper plate A27 and a lower plate A31; the purifying furnace body A10 is sleeved outside the side wall of the purifying furnace crucible A11, the top end of the purifying furnace crucible A11 is hermetically connected with the upper plate A27, a guide pipe A1 and a drain pipe A33 are arranged on the bottom plate of the purifying furnace crucible A11 to vertically communicate the bottom plate of the purifying furnace crucible A11, the guide pipe A1 and the drain pipe A33 penetrate through the lower plate A31 below the purifying furnace crucible A11, a net rack A29 is arranged at the top end of the drain pipe A33, and a filter screen A30 is covered outside the net rack A29; the argon box A9 is sleeved outside the draft tube A1, and the side wall of the draft tube A1 positioned inside the argon box A9 is provided with a plurality of vent holes; the interior of the argon box A9 is communicated with an argon pipe A8, and the argon pipe A8 is communicated with an argon gas source; the upper plate A27 is provided with a lower liquid level rod A15, an upper liquid level rod A23, a purification furnace thermocouple A19 and a vacuum tube A20; the vacuum tube A20 is used for communicating the interior of a purification furnace crucible A11 with a vacuum system, a lower liquid level rod A15, an upper liquid level rod A23 and a purification furnace thermocouple A19 are inserted into the interior of a purification furnace crucible A11, the bottom end of the upper liquid level rod A23 is higher than the bottom end of the lower liquid level rod A15, the height difference between the bottom end of the upper liquid level rod A23 and the bottom end of the lower liquid level rod A15 is 70-80% of the height of the interior space of the purification furnace crucible A11, the bottom end of the lower liquid level rod A15 is higher than a flow guide tube A1 and a flow discharge tube A33, and the bottom end of the lower liquid level rod A15 is higher than the bottom end of the purification furnace thermocouple A19; the lower plate A31 is provided with a heat preservation furnace thermocouple A2, a heat preservation furnace liquid level rod A3 and a measuring tube A32, and the measuring tube A32 is used for placing a hydrogen measuring instrument probe; the holding furnace C comprises an upper furnace body C1, a holding furnace crucible C3 and a lower furnace body C9; the upper furnace body C1 is sleeved outside the side wall of the holding furnace crucible C3, and the lower furnace body C9 is positioned below the bottom plate of the holding furnace crucible C3; a liquid inlet pipe C2 and an outflow port C5 are arranged on the side wall of the holding furnace crucible C3, and a flow control solder C8 is assembled in the outflow port C5; the heat-preserving furnace crucible C3 is hermetically connected with the lower plate A31 through a heat-preserving furnace sealing gasket B; the holding furnace thermocouple A2 and the holding furnace liquid level rod A3 are inserted into the holding furnace crucible C3; the bottom ends of the draft tube A1 and the drain tube A33 are positioned inside the crucible C3 of the holding furnace; the bottom end of the liquid level rod A3 of the holding furnace is higher than the bottom end of the thermocouple A2 of the holding furnace, and the bottom end of the thermocouple A2 of the holding furnace is higher than the bottom end of the draft tube A1; the bottom end of the drainage pipe A33 is higher than the bottom end of the draft pipe A1 and lower than the bottom end of the liquid level rod A3 of the holding furnace; wherein the upper liquid level rod A23 and the lower liquid level rod A15 are respectively insulated with the upper plate A27, and the liquid level rod A3 of the heat preservation furnace is insulated with the lower plate A31; a baffle C4 is arranged in the holding furnace crucible C3, the top edge of the baffle C4 is 20-30 mm lower than the top edge of the holding furnace crucible C3, the top edge of the baffle C4 is higher than the bottom end of the holding furnace thermocouple A2, and a passage opening is formed in the bottom edge of the baffle C4 to communicate the two sides of the baffle C4; the bottom edge of the baffle C4 is welded and fixed on the bottom plate of the furnace crucible C3, the side edge of the baffle C4 is welded and fixed on the side wall of the holding furnace crucible C3, and the baffle C4 divides the internal space of the holding furnace crucible C3 into two parts with equal volume; the liquid inlet pipe C2 and the liquid outlet C5 are respectively positioned on two sides of the baffle C4, the draft tube A1 and the discharge tube A33 are respectively positioned on two sides of the baffle C4, and the liquid inlet pipe C2 and the draft tube A1 are positioned on the same side of the baffle C4.
In the device, the inner side of a purifying furnace body A10 is provided with a heating resistance wire, the inner side of an upper furnace body C1 is provided with a heating resistance wire, and the upper part of a lower furnace body C9 is provided with a heating resistance wire.
In the device, a net rack A29 is arranged at the top end of the drainage pipe A33, and a filter screen A30 is coated outside the net rack A29; wherein the outer wall of the top end of the drainage tube A33 is fixed with 3 wing panels A33-1, the net rack A29 is composed of a net rack top plate A29-1, a net rack bottom plate A29-2 and a plurality of net rack supporting rods A29-3, the upper and lower ends of the net rack supporting rods A29-3 are respectively fixedly connected with the net rack top plate A29-1 and the net rack bottom plate A29-2, the net rack bottom plate A29-2 is provided with a notch which is respectively matched with the outer wall of the drainage tube A33 and the wing panels A33-1, the wind rack A29 is sleeved outside the drainage tube A33, the wing panels A33-1 are positioned above the non-notch of the net rack bottom plate A29-2 through rotating the net rack A29, and the net rack A29 is detached through rotating the net rack A29; the rack floor A29-2 is located between the fin A33-1 and the floor of the furnace crucible A11.
In the device, the aperture of the filter screen A30 is 20-30 meshes.
In the device, the number of the vent holes is at least 20, at least 1 row is formed on the side wall of the draft tube A1 in the argon box A9 from top to bottom, the vent holes of each row are uniformly distributed along the circumferential direction of the draft tube A1, and the aperture of each vent hole is 0.5-1.5 mm.
In the device, a holding furnace liquid level rod A3 is fixed on a lower plate A31 through a first screw pipe A5 and a first pressing cap A6, and asbestos ropes are filled between the holding furnace liquid level rod A3 and the first screw pipe A5 for sealing and insulation.
In the above apparatus, the holding furnace thermocouple A2 is fixed to the lower plate A31 via the second coil A4 and the second press cap A7.
In the above apparatus, the top end of the crucible A11 of the purification furnace is sealed with the upper plate A27 by the upper plate packing A28 and is held by being pressed by the fastening wedge A12.
In the device, the lower liquid level rod A15 is fixed on the upper plate A27 through the third screw A13 and the third pressing cap A14, and asbestos ropes are filled between the lower liquid level rod A15 and the third screw A13 for sealing and insulation.
In the above device, the purification furnace thermocouple a19 is fixed on the upper plate a27 by the fourth coil a16 and the fourth press cap a17, and asbestos cord is filled between the fourth coil a16 and the fourth press cap a17 for sealing.
In the above-described apparatus, the observation window a21 is provided on the upper plate a27, the observation window a21 is fixed to the observation tube a24 by the gland a22 and the fastening bolt a18, and the observation tube a24 is fixed to the upper plate a27 by welding.
In the device, the upper liquid level rod A23 is fixed on the upper plate A27 through the fifth screw A26 and the fifth pressure cap A25, and asbestos ropes are filled between the upper liquid level rod A23 and the fifth screw A26 for sealing and insulation.
In the device, a flow outlet pipe C7 is sleeved outside the outflow port C5, and the flow outlet pipe C7 penetrates through the upper furnace body C1; the outer wall of the outlet pipe C7 is fixedly connected with a fastening plate C6, and the fastening plate C6 is fixed on the outer wall of the upper furnace body C1 through a second fastening nut C10 and a second fastening bolt C11; the flow control drill C8 is inserted into the flow outlet C5 through the flow outlet C7; wherein the flow control drill C8 is inclined downwards by 5-10 degrees in the horizontal direction.
In the device, the inner walls of a crucible A11 of the purification furnace, a drain pipe A33 and a draft pipe A1 are coated with a coating for preventing the corrosion of aluminum-lithium alloy; the upper end surface and the lower end surface of the bleeder pipe A33 and the upper end surface and the lower end surface of the draft pipe A1 are coated with a coating for preventing aluminum-lithium alloy corrosion; the part of the outer wall of the bleeder pipe A33, which is positioned in the purification furnace crucible A11 and the holding furnace crucible C3, is coated with a coating for preventing the corrosion of the aluminum-lithium alloy; the part of the outer wall of the draft tube A1, which is positioned in the purification furnace crucible A11 and the holding furnace crucible C3, is coated with a coating for preventing the corrosion of the aluminum-lithium alloy.
In the device, the inner wall of the crucible C3 of the holding furnace and the outer surface of the baffle C4 are coated with a coating for preventing the corrosion of the aluminum-lithium alloy; the inner wall of the liquid inlet pipe C2, the inner wall of the liquid outlet C5, the inner wall of the liquid outlet pipe C7 and the outer surface of the flow control drill C8 are coated with a coating for preventing aluminum-lithium alloy corrosion; the end surface of the liquid inlet pipe C2 positioned in the holding furnace crucible C3 and the part of the outer wall of the liquid inlet pipe C2 positioned in the holding furnace crucible C3 are coated with a coating for preventing the aluminum lithium alloy from being corroded.
The paint for preventing corrosion of aluminum-lithium alloy and the coating method thereof are disclosed in patent application publication No. CN 110172627A.
The method for deeply purifying the aluminum-lithium alloy melt adopts the device and comprises the following steps:
1. heating a purification furnace crucible A11 through a purification furnace body A10, heating a heat preservation furnace crucible C3 through an upper furnace body C1 and a lower furnace body C9, and preheating a purification furnace crucible A11 and a heat preservation furnace crucible C3 to 700-750 ℃;
2. the upper liquid level rod A23 is communicated with one pole of a first liquid level power supply, the other pole of the first liquid level power supply is grounded to form a first liquid level measuring circuit, and a first indicator lamp is arranged on the first liquid level measuring circuit; communicating the lower liquid level rod A15 with one pole of a second liquid level power supply, and grounding the other pole of the second liquid level power supply to form a second liquid level measuring circuit, wherein a second indicator light is arranged on the second liquid level measuring circuit; communicating a liquid level rod A3 of the heat preservation furnace with one pole of a third liquid level power supply, and grounding the other pole of the third liquid level power supply to form a third liquid level measurement circuit, wherein a third indicator lamp is arranged on the third liquid level measurement circuit;
3. introducing the smelted aluminum-lithium alloy melt with the temperature of 700-725 ℃ into a crucible C3 of a heat preservation furnace through a liquid inlet pipe C2; when the liquid level of the aluminum lithium alloy melt entering the holding furnace crucible C3 is contacted with a holding furnace liquid level rod A3, a third liquid level measuring circuit is communicated, a third indicator lamp is lightened, then the aluminum lithium alloy liquid is stopped being conveyed to the holding furnace crucible C3, and at the moment, the liquid level of the aluminum lithium alloy melt in the holding furnace crucible C3 is higher than the bottom ends of a flow guide pipe A1 and a flow discharge pipe A33;
4. communicating a vacuum tube A20 with a vacuum system, starting the vacuum system to vacuumize the crucible A11 of the purifying furnace, and leading the aluminum-lithium alloy melt to enter the crucible A11 of the purifying furnace along a draft tube A1 along with the rise of the vacuum degree in the crucible A11 of the purifying furnace; when the liquid level of the aluminum lithium alloy melt in the purification furnace crucible A11 is higher than the bottom end of the lower liquid level rod A15, the second liquid level measuring circuit is connected, and the second indicator lamp is lightened, so that the liquid level of the aluminum lithium alloy melt in the purification furnace crucible A11 is higher than the flow guide pipe A1 and the drain pipe A33; at the moment, the liquid level of the aluminum lithium alloy melt in the crucible C3 of the holding furnace is higher than the bottom end of the draft tube A1 and lower than the bottom end of the bleeder tube A33;
5. under the condition that an argon gas pipe A8 is communicated with an argon gas source, argon gas is introduced into an argon gas box A9 through the argon gas pipe A8, the argon gas enters a guide pipe A1 through an air vent, fine argon gas bubbles are formed and mixed into the aluminum lithium alloy melt, the aluminum lithium alloy melt is dehydrogenated under the action of vacuum and the argon gas bubbles, and oxide impurities in the aluminum lithium alloy melt float upwards to a crucible A11 of a purification furnace; under the action of gravity, the aluminum-lithium alloy melt in the crucible A11 of the purification furnace enters a drain pipe A33 through a filter screen A30 and a net rack A29 and flows back to a crucible C3 of the holding furnace, and the oxide impurities are intercepted on the surface of the filter screen A30;
6. under the conditions of continuous vacuum pumping and argon gas introduction, when the liquid level of the aluminum lithium alloy melt in the crucible A11 of the purification furnace is contacted with the upper liquid level rod A23, the first liquid level measuring circuit is communicated, and the first indicator lamp is lightened; the liquid level of the aluminum lithium alloy melt in the crucible A11 of the purification furnace is reduced by reducing the vacuum degree, the first liquid level measuring electric furnace is disconnected, and the liquid level of the aluminum lithium alloy melt in the crucible A11 of the purification furnace is controlled to be positioned between the bottom end of the lower liquid level rod A15 and the bottom end of the upper liquid level rod A23 by adjusting the vacuum degree; at the moment, the liquid level of the aluminum lithium alloy melt in the crucible C3 of the holding furnace is higher than the bottom end of the draft tube A1 and lower than the bottom end of the bleeder tube A33;
7. the aluminum lithium alloy melt flowing into the holding furnace crucible C3 from the drain pipe A33 is positioned on one side of the baffle C4; under the condition of continuous vacuum pumping, the mixture enters the other side of the baffle C4 from a passage opening at the bottom of the baffle C4 and then enters the crucible A11 of the purification furnace from the draft tube A1 to form circular purification;
8. the probe of the hydrogen measuring instrument penetrates through the measuring tube A32 and is inserted into the aluminum-lithium alloy melt; measuring the hydrogen content in the aluminum lithium alloy melt in the crucible C3 of the holding furnace by a probe of a hydrogen measuring instrument, and stopping vacuumizing and introducing argon when the hydrogen content is less than or equal to 0.10ppm to finish deep purification; and pulling the flow control drill C8 to discharge the aluminum lithium alloy melt from the tap C5 and introducing the aluminum lithium alloy melt into a crystallizer for continuous casting.
In the method, a net rack A29 is arranged at the top end of a drain pipe A33, a filter screen A30 covers the net rack A29, a wing A33-1 is fixed at the top end of the drain pipe A33, a net rack A29 is sleeved outside the drain pipe A33 and the wing A33-1, and a net rack A29 is rotated to stagger a notch of a net rack bottom plate A29-2 with the wing A33-1, so that the device installation for deeply purifying the aluminum-lithium alloy melt is completed.
The device and the method of the invention use the RH method for purifying the molten steel, utilize the combined action of vacuum and argon gas, further improve the purification device and the method, develop the method and the device suitable for the deep purification of the aluminum-lithium alloy liquid, and can realize the deep dehydrogenation and deslagging of the aluminum-lithium alloy melt, thereby laying a foundation for the preparation of the aluminum-lithium alloy high-quality ingot blank.
The device adopts a double-layer structure, combines the upper-layer purification and the lower-layer heat preservation, and is provided with the upper liquid level rod and the lower liquid level rod, so that the liquid level of the aluminum-lithium alloy in the furnace is conveniently controlled, and the purification process is ensured to be carried out smoothly; argon can be blown in along the circumferential direction by adopting a small-hole argon blowing mode to form fine and uniform argon bubbles, so that hydrogen in the melt can be removed conveniently; the filter screen is arranged on the drain pipe and can filter impurities; meanwhile, components such as the crucible and the like can avoid corrosion of the aluminum lithium alloy in a coating mode; the device and the method can reduce the hydrogen content of the aluminum lithium alloy by more than 20 times, obviously reduce the maximum inclusion size of the aluminum lithium alloy formed after casting, have good flaw detection results and greatly reduce the oxide content.
Drawings
FIG. 1 is a schematic structural diagram of an apparatus for deep purification of an aluminum-lithium alloy melt in an embodiment of the present invention;
in the figure, A, a purifying furnace, B a heat preserving furnace sealing gasket, C, a heat preserving furnace;
FIG. 2 is a schematic view of the purification furnace of FIG. 1;
FIG. 3 is a top view of FIG. 2;
FIG. 4 is a schematic view taken along line A-A of FIG. 2;
FIG. 5 is a schematic view of a connection structure of a rack and a drain pipe according to an embodiment of the present invention;
fig. 6 is a schematic view of a grid structure according to an embodiment of the present invention;
FIG. 7 is a schematic view of FIG. 6 taken from direction E-E;
FIG. 8 is a schematic view of FIG. 5 taken in the direction F;
FIG. 9 is a schematic view of the holding furnace of FIG. 1;
FIG. 10 is a top view of FIG. 9;
FIG. 11 is a schematic view taken along line H of FIG. 9;
in the figure, A, a draft tube, A, a holding furnace thermocouple, A, a holding furnace liquid level rod, A, a second screw tube, A, a first press cap, A, a second press cap, A, an argon tube, A, an argon tank, A, a purifying furnace body, A, a purifying furnace crucible, A, a fastening wedge, A, a third screw tube, A, a third press cap, A, a lower liquid level rod, A, a fourth screw tube, A, a fourth press cap, A, a fastening bolt, A, a purifying furnace thermocouple, A, a vacuum tube, A, an observation window, A, a press cap, A, an upper liquid level rod, A, an observation tube, A, a fifth press cap, A, a fifth screw tube, A, an upper plate gasket, A, a net rack, A-1, net rack top plate, A-2, net rack bottom plate, A-3, net rack support, A, filter screen, A, lower plate, A, measurement tube, A, a drain tube, a33-1, a fin, C1, an upper furnace body, C2, a liquid inlet pipe, C3, a holding furnace crucible, C4, a baffle, C5, an outflow port, C6, a fastening plate, C7, an outflow pipe, C8, a flow control drill, C9, a lower furnace body, C10, a second fastening nut, C11 and a second fastening bolt.
Detailed Description
In the embodiment of the invention, the draft tube A1, the purification furnace crucible A11, the net rack A28 and the drain tube A31 are made of pure titanium or TC4 titanium alloy.
In the embodiment of the invention, the second screw tube A4, the first screw tube A5, the first pressure cap A6, the second pressure cap A7, the argon tube A8, the argon tank A9, the third screw tube A13, the third pressure cap A14, the fourth screw tube A16, the fourth pressure cap A17, the fastening bolt A18, the gland A22, the fifth pressure cap A24, the fifth screw tube A25 and the lower plate A31 are made of 304 stainless steel.
In the embodiment of the invention, the liquid level rod A3, the lower liquid level rod A15 and the upper liquid level rod A23 of the heat preservation furnace are made of tungsten.
In the embodiment of the invention, the purification furnace thermocouple A19 and the holding furnace thermocouple A2 are sheathed thermocouples.
In the embodiment of the invention, an argon box A9 is fixedly welded with an argon pipe A8, and an upper plate A26 is fixedly welded with a vacuum pipe A20.
In the embodiment of the invention, an argon box A9, a draft tube A1 and a purification furnace crucible A11 are welded and fixed with each other.
In the embodiment of the invention, the upper plate A26 is respectively welded and fixed with the third screw tube A13, the fourth screw tube A16 and the fifth screw tube A25.
In the embodiment of the invention, the lower plate A30 is respectively welded and fixed with the second spiral tube A4 and the first spiral tube A5.
In the embodiment of the invention, the inner wall of each spiral tube is connected with a fixed thermocouple or a liquid level rod through threads and is filled with asbestos ropes for sealing and insulation, and the outer wall of each spiral tube is connected and pressed with a corresponding pressing cap through threads.
The material of the heat preservation furnace sealing gasket B in the embodiment of the invention is graphite packing.
In the embodiment of the invention, the second fastening bolt C11 is welded and fixed with the upper furnace body C1, two second fastening bolts C11 penetrate through the fastening plate 6, and two second fastening nuts C10 are respectively in threaded connection with one second fastening bolt C11 to press and fix the fastening plate 6.
In the embodiment of the invention, the material of the liquid inlet pipe C2, the holding furnace crucible C3, the baffle C4, the liquid outlet C5, the fastening plate C6 and the liquid outlet pipe C7 is pure titanium or TC4 titanium alloy.
In the embodiment of the invention, the material of the flow control brazing flux C8, the second fastening nut C10 and the second fastening bolt C11 is 304 stainless steel.
In the embodiment of the invention, the observation window A21 is made of tempered heat-resistant glass.
In the embodiment of the invention, the aperture of the filter screen A29 is 20-30 meshes, and the material is titanium.
In the embodiment of the invention, the inner diameters of the draft tube A1 and the draft tube A31 are both 40-60 mm.
In the embodiment of the invention, the vent holes are totally 4 rows from top to bottom, each row of vent holes are uniformly distributed along the circumferential direction of the draft tube A1, and the distance between two adjacent vent holes of each row of vent holes is 5 mm.
In the embodiment of the invention, when the circulating purification is carried out, the temperature of the aluminum lithium alloy melt in the device for deeply purifying the aluminum lithium alloy melt is controlled to be 680-750 ℃, and preferably 700-720 ℃.
One electrode of the power supply is grounded in the embodiment of the invention, namely the power supply is in conductive connection with the device for deeply purifying the aluminum-lithium alloy melt.
The aluminum lithium alloy treated in the embodiment of the invention is 2A97Al-Li alloy, 2195 aluminum lithium alloy or 1420Al-Li alloy.
The height of the channel opening below the baffle C4 is 20-40 mm, and the width is 50-80 mm. In the embodiment of the invention, the number of the fins A33-1 is three, the fins A33-1 are fan-shaped, the radian is 60 degrees, and the fins are uniformly distributed on the circumference of the top end of the drain pipe A33.
In the embodiment of the invention, a net rack A29 is composed of a net rack top plate A29-1, a net rack bottom plate A29-2 and three net rack support rods A29-3, the upper end and the lower end of each net rack support rod A29-3 are respectively fixedly connected with a net rack top plate A29-1 and a net rack bottom plate A29-2, and a filter screen A30 covers the outside of the net rack A29 and is fixed on the net rack top plate A29-1 and the net rack bottom plate A29-2; the net rack bottom plate A29-2 is provided with a through hole and a notch which are positioned inside the net rack support rod A29-3 and are respectively matched with the outer wall of the drainage pipe A33 and the wing piece A33-1.
When the rack is installed in the embodiment of the invention, the three notches of the rack A29 are aligned with the three fins A33-1 and then inserted, so that the fins A33-1 are positioned above the bottom plate A29-2 of the rack; the rack a29 is then rotated 60 deg. so that the spaces between the three tabs are aligned with the three notches.
In the embodiment of the invention, the height of the aluminum lithium alloy in the crucible A11 of the purifying furnace is controlled to be 200-400 mm, and the vacuum degree is controlled to be 500-1000 Pa.
In the embodiment of the invention, the flow speed of the aluminum-lithium alloy in the guide pipe A1 is 5-10 Kg/min, and the flow speed of the argon in the argon pipe A8 is 50-100L/min.
The following are preferred embodiments of the present invention.
Example 1
The structure of the device for deeply purifying the aluminum-lithium alloy melt is shown in figure 1 and comprises a purifying furnace A, a heat preservation furnace sealing gasket B and a heat preservation furnace C;
the structure of the purification furnace A is shown in FIG. 2, the top view is shown in FIG. 3, and the structure in the direction of A-A is shown in FIG. 4, and comprises a purification furnace crucible A11, a purification furnace body A10, an upper plate A27 and a lower plate A31; the purifying furnace body A10 is sleeved outside the side wall of the purifying furnace crucible A11, the top end of the purifying furnace crucible A11 is hermetically connected with the upper plate A27, a guide pipe A1 and a drain pipe A33 are arranged on the bottom plate of the purifying furnace crucible A11 to vertically communicate the bottom plate of the purifying furnace crucible A11, the guide pipe A1 and the drain pipe A33 penetrate through the lower plate A31 below the purifying furnace crucible A11, a net rack A29 is arranged at the top end of the drain pipe A33, and a filter screen A30 is covered outside the net rack A29; the argon box A9 is sleeved outside the draft tube A1, and the side wall of the draft tube A1 positioned inside the argon box A9 is provided with a plurality of vent holes; the interior of the argon box A9 is communicated with an argon pipe A8, and the argon pipe A8 is communicated with an argon gas source; the upper plate A27 is provided with a lower liquid level rod A15, an upper liquid level rod A23, a purification furnace thermocouple A19 and a vacuum tube A20; the vacuum tube A20 is used for communicating the interior of a purification furnace crucible A11 with a vacuum system, a lower liquid level rod A15, an upper liquid level rod A23 and a purification furnace thermocouple A19 are inserted into the interior of a purification furnace crucible A11, the bottom end of the upper liquid level rod A23 is higher than the bottom end of the lower liquid level rod A15, the height difference between the bottom end of the upper liquid level rod A23 and the bottom end of the lower liquid level rod A15 is 70-80% of the height of the interior space of the purification furnace crucible A11, the bottom end of the lower liquid level rod A15 is higher than a flow guide tube A1 and a flow discharge tube A33, and the bottom end of the lower liquid level rod A15 is higher than the bottom end of the purification furnace thermocouple A19; the lower plate A31 is provided with a heat preservation furnace thermocouple A2, a heat preservation furnace liquid level rod A3 and a measuring tube A32, and the measuring tube A32 is used for placing a hydrogen measuring instrument probe;
the structure of the holding furnace C is shown in FIG. 9, the top view is shown in FIG. 10, the H-direction structure is shown in FIG. 11, and the H-direction structure comprises an upper furnace body C1, a holding furnace crucible C3 and a lower furnace body C9; the upper furnace body C1 is sleeved outside the side wall of the holding furnace crucible C3, and the lower furnace body C9 is positioned below the bottom plate of the holding furnace crucible C3; a liquid inlet pipe C2 and an outflow port C5 are arranged on the side wall of the holding furnace crucible C3, and a flow control solder C8 is assembled in the outflow port C5; the heat-preserving furnace crucible C3 is hermetically connected with the lower plate A31 through a heat-preserving furnace sealing gasket B; the holding furnace thermocouple A2 and the holding furnace liquid level rod A3 are inserted into the holding furnace crucible C3; the bottom ends of the draft tube A1 and the drain tube A33 are positioned inside the crucible C3 of the holding furnace; the bottom end of the liquid level rod A3 of the holding furnace is higher than the bottom end of the thermocouple A2 of the holding furnace, and the bottom end of the thermocouple A2 of the holding furnace is higher than the bottom end of the draft tube A1; the bottom end of the drainage pipe A33 is higher than the bottom end of the draft pipe A1 and lower than the bottom end of the liquid level rod A3 of the holding furnace; wherein the upper liquid level rod A23 and the lower liquid level rod A15 are respectively insulated with the upper plate A27, and the liquid level rod A3 of the heat preservation furnace is insulated with the lower plate A31; a baffle C4 is arranged in the holding furnace crucible C3, the top edge of the baffle C4 is 20-30 mm lower than the top edge of the holding furnace crucible C3, the top edge of the baffle C4 is higher than the bottom end of the holding furnace thermocouple A2, and a passage opening is formed in the bottom edge of the baffle C4 to communicate the two sides of the baffle C4; the bottom edge of the baffle C4 is welded and fixed on the bottom plate of the furnace crucible C3, the side edge of the baffle C4 is welded and fixed on the side wall of the holding furnace crucible C3, and the baffle C4 divides the internal space of the holding furnace crucible C3 into two parts with equal volume; the liquid inlet pipe C2 and the liquid outlet C5 are respectively positioned at two sides of the baffle C4, the draft tube A1 and the discharge tube A33 are respectively positioned at two sides of the baffle C4, and the liquid inlet pipe C2 and the draft tube A1 are positioned at the same side of the baffle C4;
the inner side of the purifying furnace body A10 is provided with a heating resistance wire, the inner side of the upper furnace body C1 is provided with a heating resistance wire, and the upper part of the lower furnace body C9 is provided with a heating resistance wire;
the top end of the drain pipe A33 is provided with a net rack A29, and a filter screen A30 covers the outside of the net rack A29; the outer wall of the top end of the drainage pipe A33 is fixed with a plurality of wing pieces A33-1, a net rack A29 is composed of a net rack top plate A29-1, a net rack bottom plate A29-2 and a plurality of net rack support rods A29-3, the upper end and the lower end of each net rack support rod A29-3 are respectively fixedly connected with the net rack top plate A29-1 and the net rack bottom plate A29-2, the net rack bottom plate A29-2 is provided with through holes and notches, the through holes and the notches are respectively matched with the outer wall of the drainage pipe A33 and the wing pieces A33-1, the net rack A29 is sleeved outside the drainage pipe A33, the wing pieces A33-1 are positioned above the non-notch of the net rack bottom plate A29-2 through the rotation of the net rack A29, and the net rack A29 is detached through the rotation of the net rack A29; the net rack bottom plate A29-2 is positioned between the fin A33-1 and the bottom plate of the purification furnace crucible A11; the connecting structure is shown in fig. 5, the structure of the net rack A29 is shown in fig. 6, the structure of the E-E direction is shown in fig. 7, and the structure of the F direction is shown in fig. 8;
the liquid level rod A3 of the holding furnace is fixed on the lower plate A31 through a first spiral pipe A5 and a first pressing cap A6, and asbestos ropes are filled between the liquid level rod A3 of the holding furnace and the first spiral pipe A5 for sealing and insulation;
the holding furnace thermocouple A2 is fixed on the lower plate A31 through a second screw pipe A4 and a second pressing cap A7;
the top end of the crucible A11 of the purification furnace is sealed with the upper plate A27 through an upper plate gasket A28 and is pressed and fixed together through a fastening wedge A12;
the lower liquid level rod A15 is fixed on the upper plate A27 through a third screw pipe A13 and a third pressure cap A14, and an asbestos rope is filled between the lower liquid level rod A15 and the third screw pipe A13 for sealing and insulation;
the purification furnace thermocouple A19 is fixed on the upper plate A27 through a fourth screw tube A16 and a fourth pressing cap A17, and asbestos ropes are filled between the fourth screw tube A16 and the fourth pressing cap A17 for sealing;
an observation window A21 is arranged on the upper plate A27, the observation window A21 is fixed on an observation tube A24 through a gland A22 and a fastening bolt A18, and an observation tube A24 is fixed on the upper plate A27 in a welding mode;
the upper liquid level rod A23 is fixed on the upper plate A27 through a fifth solenoid A26 and a fifth pressure cap A25, and asbestos ropes are filled between the upper liquid level rod A23 and the fifth solenoid A26 for sealing and insulation;
a flow outlet pipe C7 is sleeved outside the flow outlet C5, and the flow outlet pipe C7 penetrates through the upper furnace body C1; the outer wall of the outlet pipe C7 is fixedly connected with a fastening plate C6, and the fastening plate C6 is fixed on the outer wall of the upper furnace body C1 through a second fastening nut C10 and a second fastening bolt C11; the flow control drill C8 is inserted into the flow outlet C5 through the flow outlet C7; the flow control brazing flux C8 inclines downwards by 5-10 degrees in the horizontal direction;
the inner walls of the crucible A11 of the purification furnace, the drain pipe A33 and the draft pipe A1 are coated with a coating for preventing aluminum-lithium alloy corrosion; the upper end surface and the lower end surface of the bleeder pipe A33 and the upper end surface and the lower end surface of the draft pipe A1 are coated with a coating for preventing aluminum-lithium alloy corrosion; the part of the outer wall of the bleeder pipe A33, which is positioned in the purification furnace crucible A11 and the holding furnace crucible C3, is coated with a coating for preventing the corrosion of the aluminum-lithium alloy; the part of the outer wall of the draft tube A1, which is positioned in the purification furnace crucible A11 and the holding furnace crucible C3, is coated with a coating for preventing aluminum-lithium alloy corrosion;
coating the inner wall of the holding furnace crucible C3 and the outer surface of the baffle C4 with a coating for preventing the corrosion of the aluminum-lithium alloy; the inner wall of the liquid inlet pipe C2, the inner wall of the liquid outlet C5, the inner wall of the liquid outlet pipe C7 and the outer surface of the flow control drill C8 are coated with a coating for preventing aluminum-lithium alloy corrosion; the end surface of the liquid inlet pipe C2 positioned in the holding furnace crucible C3 and the part of the outer wall of the liquid inlet pipe C2 positioned in the holding furnace crucible C3 are coated with a coating for preventing the corrosion of the aluminum lithium alloy;
the method comprises the following steps:
heating a purification furnace crucible A11 through a purification furnace body A10, heating a heat preservation furnace crucible C3 through an upper furnace body C1 and a lower furnace body C9, and preheating a purification furnace crucible A11 and a heat preservation furnace crucible C3 to 700-750 ℃;
the upper liquid level rod A23 is communicated with one pole of a first liquid level power supply, the other pole of the first liquid level power supply is grounded to form a first liquid level measuring circuit, and a first indicator lamp is arranged on the first liquid level measuring circuit; communicating the lower liquid level rod A15 with one pole of a second liquid level power supply, and grounding the other pole of the second liquid level power supply to form a second liquid level measuring circuit, wherein a second indicator light is arranged on the second liquid level measuring circuit; communicating a liquid level rod A3 of the heat preservation furnace with one pole of a third liquid level power supply, and grounding the other pole of the third liquid level power supply to form a third liquid level measurement circuit, wherein a third indicator lamp is arranged on the third liquid level measurement circuit;
introducing the smelted aluminum-lithium alloy melt with the temperature of 700-725 ℃ into a crucible C3 of a heat preservation furnace through a liquid inlet pipe C2; when the liquid level of the aluminum lithium alloy melt entering the holding furnace crucible C3 is contacted with a holding furnace liquid level rod A3, a third liquid level measuring circuit is communicated, a third indicator lamp is lightened, then the aluminum lithium alloy liquid is stopped being conveyed to the holding furnace crucible C3, and at the moment, the liquid level of the aluminum lithium alloy melt in the holding furnace crucible C3 is higher than the bottom ends of a flow guide pipe A1 and a flow discharge pipe A33;
communicating a vacuum tube A20 with a vacuum system, starting the vacuum system to vacuumize the crucible A11 of the purifying furnace, and leading the aluminum-lithium alloy melt to enter the crucible A11 of the purifying furnace along a draft tube A1 along with the rise of the vacuum degree in the crucible A11 of the purifying furnace; when the liquid level of the aluminum lithium alloy melt in the purification furnace crucible A11 is higher than the bottom end of the lower liquid level rod A15, the second liquid level measuring circuit is connected, and the second indicator lamp is lightened, so that the liquid level of the aluminum lithium alloy melt in the purification furnace crucible A11 is higher than the flow guide pipe A1 and the drain pipe A33; at the moment, the liquid level of the aluminum lithium alloy melt in the crucible C3 of the holding furnace is higher than the bottom end of the draft tube A1 and the bottom end of the bleeder tube A33;
under the condition that an argon gas pipe A8 is communicated with an argon gas source, argon gas is introduced into an argon gas box A9 through the argon gas pipe A8, the argon gas enters a guide pipe A1 through an air vent, fine argon gas bubbles are formed and mixed into the aluminum lithium alloy melt, the aluminum lithium alloy melt is dehydrogenated under the action of vacuum and the argon gas bubbles, and oxide impurities in the aluminum lithium alloy melt float upwards to a crucible A11 of a purification furnace; under the action of gravity, the aluminum-lithium alloy melt in the crucible A11 of the purification furnace enters a drain pipe A33 through a filter screen A30 and flows back to a crucible C3 of the holding furnace, and oxide impurities are trapped on the surface of the filter screen A30;
under the conditions of continuous vacuum pumping and argon gas introduction, when the liquid level of the aluminum lithium alloy melt in the crucible A11 of the purification furnace is contacted with the upper liquid level rod A23, the first liquid level measuring circuit is communicated, and the first indicator lamp is lightened; the liquid level of the aluminum lithium alloy melt in the crucible A11 of the purification furnace is reduced by reducing the vacuum degree, the first liquid level measuring electric furnace is disconnected, and the liquid level of the aluminum lithium alloy melt in the crucible A11 of the purification furnace is controlled to be positioned between the bottom end of the lower liquid level rod A15 and the bottom end of the upper liquid level rod A23 by adjusting the vacuum degree; at the moment, the liquid level of the aluminum lithium alloy melt in the crucible C3 of the holding furnace is higher than the bottom end of the draft tube A1 and the bottom end of the bleeder tube A33;
the aluminum lithium alloy melt flowing into the holding furnace crucible C3 from the drain pipe A33 is positioned on one side of the baffle C4; under the condition of continuous vacuum pumping, the mixture enters the other side of the baffle C4 from a passage opening at the bottom of the baffle C4 and then enters the crucible A11 of the purification furnace from the draft tube A1 to form circular purification;
the probe of the hydrogen measuring instrument penetrates through the measuring tube A32 and is inserted into the aluminum-lithium alloy melt; measuring the hydrogen content in the aluminum lithium alloy melt in the crucible C3 of the holding furnace by a probe of a hydrogen measuring instrument, and stopping vacuumizing and introducing argon when the hydrogen content is less than or equal to 0.10ppm to finish deep purification; pulling the flow control brazing flux C8 to discharge the aluminum lithium alloy melt from the outflow port C5 and introducing the aluminum lithium alloy melt into a crystallizer for continuous casting;
the treated aluminum-lithium alloy is 2A97Al-Li alloy, and comprises the components of, by mass, 4.19% of Cu, 0.41% of Mg, 0.43% of Li1.43% of Zr, 0.12% of Mn, 0.11% of Fe, 0.04% of Si, and the balance of Al;
the size of a crucible of a purifying furnace adopted is 300 (inner diameter) multiplied by 520mm, the size of a crucible of a holding furnace is 600 (inner diameter) multiplied by 300mm, the size of a draft tube is 50 (inner diameter) multiplied by 450mm, and the size of a discharge tube is 50 (inner diameter) multiplied by 400 mm;
during deep purification, the temperature of the aluminum lithium alloy when the aluminum lithium alloy is introduced into a crucible C3 of a holding furnace is 720 ℃, the temperature of the aluminum lithium alloy discharged from an outflow port C5 is 708 ℃, and the purification time is 20 min; when continuous casting is carried out, the casting speed is 90mm/min, the diameter of the prepared cast ingot is 176mm, the maximum slag inclusion size is 0.15mm, the area fraction of inclusions is 0.02 percent, the ultrasonic flaw detection result is A, and the hydrogen content is 0.08 ppm;
continuously casting the aluminum-lithium alloy with the same material by adopting a traditional chute argon protection continuous casting method, wherein the maximum slag inclusion size of the obtained cast ingot is 2.8mm, the area fraction of inclusions is 0.1%, the ultrasonic flaw detection result is B, and the hydrogen content is 2 ppm;
compared with the traditional chute argon protection continuous casting method, the 2A97 alloy ingot obtained by the embodiment has the advantages of reduced size of large oxide, reduced hydrogen content and good flaw detection result.
Example 2
The structure of the device for deeply purifying the aluminum lithium alloy melt is the same as that of the device in the embodiment 1;
the method is the same as example 1, except that:
(1) the treated aluminum-lithium alloy is 2195Al-Li alloy, and comprises the following components, by mass, 4.2% of Cu, 0.43% of Mg, 1.28% of Li, 0.13% of Zr, 0.38% of Ag, 0.09% of Fe, 0.04% of Si, and the balance of Al;
(2) during deep purification, the temperature of the aluminum lithium alloy when the aluminum lithium alloy is introduced into a crucible C3 of a holding furnace is 712 ℃, the temperature of the aluminum lithium alloy discharged from an outflow port C5 is 702 ℃, and the purification time is 20 min; when continuous casting is carried out, the casting speed is 70mm/min, and the diameter of the prepared cast ingot is 200 mm; the maximum slag inclusion size is 0.9mm, the area fraction of inclusions is 0.03 percent, the ultrasonic flaw detection result is A, and the hydrogen content is 0.08 ppm;
continuously casting the aluminum-lithium alloy with the same material by adopting a traditional chute argon protection continuous casting method, wherein the maximum slag inclusion size of the obtained cast ingot is 3.2mm, the area fraction of inclusions is 0.12%, the ultrasonic flaw detection result is B, and the hydrogen content is 2.6 ppm;
compared with the traditional chute argon protection continuous casting method, the 2195 alloy ingot obtained by the method has the advantages of reduced size of the oxide of the large block, reduced hydrogen content and good flaw detection result.
Example 3
The structure of the device for deeply purifying the aluminum lithium alloy melt is the same as that of the device in the embodiment 1;
the method is the same as example 1, except that:
(1) the treated aluminum-lithium alloy is 1420Al-Li alloy, which comprises the following components, by mass, 4.88% of Mg, 2.05% of Li, 0.13% of Zr, 0.12% of Fe, 0.11% of Si, and the balance of Al;
(2) during deep purification, the temperature of the aluminum lithium alloy when the aluminum lithium alloy is introduced into a crucible C3 of a holding furnace is 710 ℃, the temperature of the aluminum lithium alloy discharged from an outflow port C5 is 697 ℃, and the purification time is 30 min; when continuous casting is carried out, the casting speed is 50mm/min, and the diameter of the prepared cast ingot is 300 mm; the maximum slag inclusion size is 1.3mm, the area fraction of inclusions is 0.08 percent, the ultrasonic flaw detection result is A, and the hydrogen content is 0.10 ppm;
continuously casting the aluminum-lithium alloy with the same material by adopting a traditional chute argon protection continuous casting method, wherein the maximum slag inclusion size of the obtained cast ingot is 5.4mm, the area fraction of inclusions is 0.22%, the ultrasonic flaw detection result is B, and the hydrogen content is 2.8 ppm;
compared with the traditional chute argon protection continuous casting method, the 1420 alloy ingot obtained by the embodiment has the advantages of reduced size of oxides, reduced hydrogen content and good flaw detection result.

Claims (7)

1. A device for deeply purifying an aluminum-lithium alloy melt is characterized by consisting of a purifying furnace, a heat preservation furnace sealing gasket and a heat preservation furnace; the purification furnace comprises a purification furnace crucible, a purification furnace body, an upper plate and a lower plate; the purifying furnace body is sleeved outside the side wall of the purifying furnace crucible, the top end of the purifying furnace crucible is hermetically connected with the upper plate, the bottom plate of the purifying furnace crucible is provided with a flow guide pipe and a flow discharge pipe which are used for communicating the bottom plate of the purifying furnace crucible up and down, the flow guide pipe and the flow discharge pipe penetrate through the lower plate below the purifying furnace crucible, the top end of the flow discharge pipe is provided with a net rack, and a filter screen is coated outside the net rack; the argon box is sleeved outside the flow guide pipe, and a plurality of vent holes are formed in the side wall of the flow guide pipe positioned in the argon box; the inner part of the argon box is communicated with an argon pipe, and the argon pipe is communicated with an argon source; the upper plate is provided with a lower liquid level rod, an upper liquid level rod, a purification furnace thermocouple and a vacuum tube; the vacuum tube is used for communicating the interior of the purification furnace crucible with a vacuum system, the lower liquid level rod, the upper liquid level rod and the purification furnace thermocouple are inserted into the purification furnace crucible, the bottom end of the upper liquid level rod is higher than the bottom end of the lower liquid level rod, the height difference between the bottom end of the upper liquid level rod and the bottom end of the lower liquid level rod is 70-80% of the height of the interior space of the purification furnace crucible, the bottom end of the lower liquid level rod is higher than the flow guide tube and the flow discharge tube, and the bottom end of the lower liquid level rod is higher than the bottom end of the purification furnace thermocouple; the lower plate is provided with a heat preservation furnace thermocouple, a heat preservation furnace liquid level rod and a measuring pipe, and the measuring pipe is used for placing a hydrogen measuring instrument probe; the heat preservation furnace comprises an upper furnace body, a heat preservation furnace crucible and a lower furnace body; the upper furnace body is sleeved outside the side wall of the crucible of the heat preservation furnace, and the lower furnace body is positioned below the bottom plate of the crucible of the heat preservation furnace; a liquid inlet pipe and an outlet are arranged on the side wall of the crucible of the holding furnace, and a flow control drill rod is assembled in the outlet; the crucible of the holding furnace is hermetically connected with the lower plate through a sealing gasket of the holding furnace; the thermo-electric couple of the holding furnace and the liquid level rod of the holding furnace are inserted into the crucible of the holding furnace; the bottom ends of the flow guide pipe and the flow discharge pipe are positioned in the crucible of the holding furnace; the bottom end of the liquid level rod of the heat preservation furnace is higher than the bottom end of the thermocouple of the heat preservation furnace, and the bottom end of the thermocouple of the heat preservation furnace is higher than the bottom end of the flow guide pipe; the bottom end of the drainage pipe is higher than the bottom end of the flow guide pipe and lower than the bottom end of the liquid level rod of the heat preservation furnace; wherein the upper liquid level rod and the lower liquid level rod are respectively insulated from the upper plate, and the liquid level rod of the heat preservation furnace is insulated from the lower plate; a baffle is arranged in the crucible of the holding furnace, the top edge of the baffle is 20-30 mm lower than the top edge of the crucible of the holding furnace, the top edge of the baffle is higher than the bottom end of the thermocouple of the holding furnace, and a passage opening is formed in the bottom edge of the baffle to communicate the two sides of the baffle; the bottom edge of the baffle is welded and fixed on a bottom plate of the crucible of the furnace, the side edge of the baffle is welded and fixed on the side wall of the crucible of the holding furnace, and the baffle divides the internal space of the crucible of the holding furnace into two parts with equal volume; the liquid inlet pipe and the liquid outlet are respectively positioned at two sides of the baffle, the flow guide pipe and the flow discharge pipe are respectively positioned at two sides of the baffle, and the liquid inlet pipe and the flow guide pipe are positioned at the same side of the baffle; the top end of the drainage pipe is provided with a net rack, and the filter screen is coated outside the net rack; wherein 3 wing pieces are fixed on the outer wall of the top end of the drainage pipe, the net rack is composed of a net rack top plate, a net rack bottom plate and a plurality of net rack supporting rods, the upper end and the lower end of each net rack supporting rod are respectively fixedly connected with the net rack top plate and the net rack bottom plate, and the net rack bottom plate is provided with a notch which is respectively matched with the outer wall of the drainage pipe and the wing pieces, so that the net rack is sleeved outside the drainage pipe, the wing pieces are positioned above the non-notch parts of the net rack bottom plate through a rotating net rack, and the net rack is dismantled through the rotating net rack; the net rack bottom plate is positioned between the fin and the bottom plate of the purification furnace crucible.
2. The device for deeply purifying the aluminum-lithium alloy melt according to claim 1, wherein the number of the vent holes is at least 20, the vent holes are arranged in at least 1 row on the side wall of the draft tube in the argon box from top to bottom, the vent holes of each row are uniformly distributed along the circumferential direction of the draft tube, and the aperture of each vent hole is 0.5-1.5 mm.
3. The device for deeply purifying the aluminum-lithium alloy melt according to claim 1, wherein the upper plate is provided with an observation window, the observation window is fixed on the observation tube through a gland and a fastening bolt, and the observation tube is welded and fixed on the upper plate.
4. The device for deeply purifying the aluminum-lithium alloy melt according to claim 1, wherein the outflow pipe is sleeved outside the outflow port and penetrates through the upper furnace body; the outer wall of the outflow pipe is fixedly connected with a fastening plate, and the fastening plate is fixed on the outer wall of the upper furnace body through a second fastening nut and a second fastening bolt; the flow control drill rod penetrates through the flow outlet pipe and is inserted into the flow outlet; wherein the flow control drill rod inclines downwards by 5-10 degrees in the horizontal direction.
5. The apparatus for deep purification of aluminum-lithium alloy melt as claimed in claim 1, wherein the inner walls of the purification furnace crucible, the drain pipe and the draft pipe are coated with a coating material for preventing corrosion of aluminum-lithium alloy; coating aluminum-lithium alloy corrosion-resistant paint on the upper end surface and the lower end surface of the flow discharge pipe and the upper end surface and the lower end surface of the flow guide pipe; the part of the outer wall of the discharge pipe, which is positioned in the purification furnace crucible and the heat preservation furnace crucible, is coated with a coating for preventing aluminum-lithium alloy corrosion; the parts of the outer wall of the guide pipe, which are positioned in the purification furnace crucible and the heat preservation furnace crucible, are coated with the coating for preventing the aluminum-lithium alloy from being corroded.
6. The device for deeply purifying the aluminum-lithium alloy melt according to claim 1, wherein the aperture of the filter screen is 20-30 meshes.
7. A method for deeply purifying an aluminum-lithium alloy melt, which is characterized by comprising the following steps of:
(1) heating a purification furnace crucible through a purification furnace body, heating a heat preservation furnace crucible through an upper furnace body and a lower furnace body, and preheating the purification furnace crucible and the heat preservation furnace crucible to 700-750 ℃;
(2) the upper liquid level rod is communicated with one pole of a first liquid level power supply, the other pole of the first liquid level power supply is grounded, a first liquid level measuring circuit is formed, and a first indicator lamp is arranged on the first liquid level measuring circuit; communicating the lower liquid level rod with one pole of a second liquid level power supply, and grounding the other pole of the second liquid level power supply to form a second liquid level measuring circuit, wherein a second indicator light is arranged on the second liquid level measuring circuit; communicating the liquid level rod of the heat preservation furnace with one pole of a third liquid level power supply, and grounding the other pole of the third liquid level power supply to form a third liquid level measuring circuit, wherein a third indicator lamp is arranged on the third liquid level measuring circuit;
(3) introducing the smelted aluminum-lithium alloy melt with the temperature of 700-725 ℃ into a crucible of a heat preservation furnace through a liquid inlet pipe; when the liquid level of the aluminum lithium alloy melt entering the crucible of the holding furnace is contacted with the liquid level rod of the holding furnace, the third liquid level measuring circuit is communicated, the third indicator lamp is lightened, then the aluminum lithium alloy liquid is stopped being conveyed to the crucible of the holding furnace, and at the moment, the liquid level of the aluminum lithium alloy melt in the crucible of the holding furnace is higher than the bottom ends of the flow guide pipe and the flow discharge pipe;
(4) communicating the vacuum tube with a vacuum system, starting the vacuum system to vacuumize the crucible of the purification furnace, and allowing the aluminum-lithium alloy melt to enter the crucible of the purification furnace along a flow guide tube along with the increase of the vacuum degree in the crucible of the purification furnace; when the liquid level of the aluminum lithium alloy melt in the crucible of the purification furnace is higher than the bottom end of the lower liquid level rod, the second liquid level measuring circuit is communicated, the second indicator lamp is lightened, and the liquid level of the aluminum lithium alloy melt in the crucible of the purification furnace is higher than the flow guide pipe and the flow discharge pipe; at the moment, the liquid level of the aluminum lithium alloy melt in the crucible of the holding furnace is higher than the bottom end of the flow guide pipe and lower than the bottom end of the flow discharge pipe;
(5) under the condition that an argon pipe is communicated with an argon gas source, argon is introduced into an argon box through the argon pipe, the argon enters a guide pipe through an air vent, fine argon bubbles are formed and mixed into the aluminum-lithium alloy melt, the aluminum-lithium alloy melt is dehydrogenated under the action of vacuum and the argon bubbles, and oxide impurities in the aluminum-lithium alloy melt float upwards to a crucible of a purification furnace; under the action of gravity, the aluminum-lithium alloy melt in the crucible of the purification furnace enters the drain pipe through the filter screen and the net rack and flows back to the crucible of the holding furnace, and the oxide impurities are intercepted on the surface of the filter screen;
(6) under the conditions of continuous vacuum pumping and argon gas introduction, when the liquid level of the aluminum lithium alloy melt in the crucible of the purifying furnace contacts the upper liquid level rod, the first liquid level measuring circuit is communicated, and the first indicator lamp is lightened; the liquid level of the aluminum lithium alloy melt in the crucible of the purifying furnace is reduced by reducing the vacuum degree, the first liquid level measuring electric furnace is disconnected, and the liquid level of the aluminum lithium alloy melt in the crucible of the purifying furnace is controlled to be positioned between the bottom end of the lower liquid level rod and the bottom end of the upper liquid level rod by adjusting the vacuum degree; at the moment, the liquid level of the aluminum lithium alloy melt in the crucible of the holding furnace is higher than the bottom end of the flow guide pipe and lower than the bottom end of the flow discharge pipe;
(7) the aluminum lithium alloy melt flowing into the crucible of the holding furnace from the drainage pipe is positioned on one side of the baffle; under the condition of continuous vacuum pumping, the waste water enters the other side of the baffle from a passage opening at the bottom of the baffle and then enters a crucible of a purification furnace from a guide pipe to form circular purification;
(8) a probe of the hydrogen measuring instrument penetrates through the measuring tube and is inserted into the aluminum-lithium alloy melt; measuring the hydrogen content in the aluminum lithium alloy melt in the crucible of the holding furnace by a probe of a hydrogen measuring instrument, and stopping vacuumizing and introducing argon when the hydrogen content is less than or equal to 0.10ppm to finish deep purification; and pulling the flow control brazing rod to discharge the aluminum lithium alloy melt from the outflow port, and introducing the aluminum lithium alloy melt into a crystallizer for continuous casting.
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