CN1009256B - Smelting-casting equipment and method for aluminium lithium alloy - Google Patents

Abstract

The present invention provides a hydrogen fusion casting device and a method for easily oxidized alloy in protective gases. Two smelting systems are respectively protected by inert gases, a two-step refining method is completed in the same crucible, and the semi-continuous casting can be carried out. The device and the method of the present invention are suitable for laboratory research or mass production. A protective coating material containing magnesium oxide is developed and coated on the surface of a vessel tool making contact with alloy in the fusion casting process, so that the alloy is not polluted, and the vessel tool is not corroded. The present invention opens up a new way of using steel vessels made by easily oxidized alloy in a fusion casting mode.

Description

Smelting-casting equipment and method for aluminium lithium alloy

The present invention relates to a kind of improved easy oxide alloy protective atmosphere smelting-casting equipment and method thereof, particularly be applicable to Al-Li alloy smelting-casting equipment and method.

The Al-Li alloy light specific gravity, the lithium of every adding 1% in aluminium, alloy material proportion then reduce by 3% Young's modulus and improve 6%, and Al-Li alloy generally contains lithium 2～3% now, if the lithium of adding 1% can alleviate more than 10% than common aluminum alloy in aluminium, be kind of an extremely promising aerospace structured material.Because lithium is kind of a precious metal; chemical property is very active; very easily oxidization burning loss waste; Al-Li alloy under the founding state very easily with its surrounding medium generation chemical reaction; can corrode the furnace wall, pollute alloy, this just makes the chemical ingredients of alloy be difficult to control; and at semicontinuous casting interalloy liquid if meeting water can blast, therefore easily the founding of oxide alloy must be adopted special equipment and method.

At present have only manufacturer of a few family few in number to grasp founding Al-Li alloy technology in the world, and particular content holds in close confidence, in a U.S. Pat 4248630, described when melting aluminum base alloy ingot, add the method for alloying element, i.e. the manufacture method of Al-Li alloy.It at first places two smelting furnaces to lithium and aluminium respectively, carries out melting according to promptly fixed technological process, and the lithium stove will feed rare gas element protected.After treating that Metal Melting is good, open lithium stove one side valve door, its liquation is transported in the measuring apparatus, determine value, open valve again lithium liquid is transported in the holding furnace by alloy proportion.While opened molten aluminium furnace side valve, aluminum melt is transported in the holding furnace, thus, use mechanical stirring, after the alloy homogenizing, just during the check valve of opening holding furnace is again got the raw materials ready the input of alloy liquid, open the feed valve of the device of getting the raw materials ready when casting, alloy liquid is injected into finishes alloy cast ingot work in the casting equipment.This production method program is more, and complicated operation, alloy property are stable inadequately.Therefore make significant improvement in other part 4556535 pairs of aforesaid operations technology of U.S. Pat, adopt computer program control automatization, the concentration of alloy, the casting area of mold requires in the alloy data entry terminals such as lithium content; With aluminium, lithium cast flow rate temperature data input computer, realize producing whole automatizations again.If it is nonconforming that terminal detects alloy proportion automatically, then regulate the flow rate of lithium molten metal by feedback signal.Above-mentioned technology adds rare gas element and protects in the molten process of lithium, and its furnace wall and transport pipe use refractory materials or other material to make lining, here what undeclared " other materials " be, for the also undeclared requirement of instrument vessel material and the protection of contact Al-Li alloy liquid.Yet, used apparatus made of iron if both made when casting, just could make the alloy iron-holder reach 0.9%～2.3% more than! And apparatus also produced corrosion.This method only is applicable to large-scale production, and technical difficulty is big, and amount of investment is also big, and the consumption of rare gas element is also very big, refractory materials use cost height, and complex process also need be prepared the seam binding agent, is unsuitable for small serial production or experimental study and uses.

The objective of the invention is to avoid above-mentioned weak point, and make a kind ofly in same smelting furnace, carry out the continuous fusion-cast method of Al-Li alloy, and the equipment of this method of realization.

Of the present inventionly finish as follows: at first make the equipment that smelting system and casting system are arranged, smelting system is by body of heater (1), common irony crucible (2), feed rare gas element pipeline (3), the crucible cover (4) that has charging opening, feeding cover (5) is formed, and pipeline (3) is on crucible cover (4), and crucible (2) lower side has cast gate.Casting system is by chute shield cap (6), outer protective cover (7), chute (8), rare gas element passage (9), foam ceramic filter (10), open and close cast gate stopper (11), viewing window (12) is checked casting crystalline hole (13), handle hole (14), water inlet cooling tube (15), Crystallizer Alloy (16), casting machine compositions such as (17).Body of heater (1) also can use ready-made article with casting machine (17).Do not pollute yet corrosion tool not of alloy for founding in addition, adopt branch's protection of inert gas and two-step refining method, and non-ferrous metal and alloy casting protective coating thereof.

Be described in further detail below in conjunction with structure iron of the present invention:

The Al-Li alloy smelting-casting equipment that Fig. 1 the present invention adopts

With reference to Fig. 1; when carrying out founding work; at first irony crucible (2) and employed tool surfaces are smeared protective coating; this coating is formulated by magnesium oxide etc.; have strong adhesion, even compact is easy to characteristics such as cleaning; it can protect instrument not to be etched, and ensures that again alloy is not contaminated, the weave construction composition reaches gold standard.Next is to add the aluminium material in crucible (2), need not add a cover, and aluminum melting process melting under atmosphere routinely, and then use C ₂Cl ₆Carry out refining, remove on most of gas and the slag inclusion bonnet behind the crucible cover (4) and feeding cover (5), feed dry argon gas from pipeline (3), because air specific weight is lighter than argon gas, so just rushed to the top in atmosphere by row.Open feeding cover (5) adding lithium again and carry out refining; then remove gas and the impurity brought into when adding lithium; because of crucible cover (4) opening little; so the short period of time does not open and can cause severe oxidation; the consumption of argon is not understood many yet; this has just solved the contradiction of smelting operation and anti-oxidation; and under feeding cover (5) lid mouthful size constancy situation; can increase the volume of crucible as required; but can not influence rare gas element losing quantity and protection effect, outer protective cover (7) casts in assurance in the sealed vessel and carries out, and enters argon gas by passage (9) during casting; open stopper (11) then; liquid alloy passes filtering net (10) to crystallizer (6) through chute (8), arrives at last in the casting machine (17); this cast form needing have been avoided crucible (2) to tilt and has been made structure complicated; cast gate has certain distance to crucible (2) bottom, and this can make the bigger impurity of proportion again, is deposited on the bottom of crucible (2); avoid causing alloy defect, guaranteed metallurgical quality with the molten metal outflow.Shield cap (6) makes into two portions syndeton form for ease of dismounting.

Simple in structure through the smelting-casting equipment that uses the checking Al-Li alloy; cheap have only 1/5～1/6 of vacuum smelting furnace; easy to operate; adopt the two-step refining method to reduce the scaling loss of lithium effectively; the favorable protection measure is reduced to below 3% the burn out rate of lithium in addition; melting is used argon shield with casting branch; be in the protection of inert gas atmosphere when making in the alloy casting process and carry out; prevent the smelting metal oxidation and save the rare gas element consumption; the founding of 30kg Al-Li alloy ingot consumes 1/3～1/2 bottle of argon gas, and produced Al-Li alloy quality reaches world-class levels fully.

Claims (3)

1, a kind of casting method of Al-Li alloy; with aluminium, lithium melting respectively, the back determines the feed flow rate by proportioning, carries out mixing and stirring earlier; in the temporary device of getting the raw materials ready; so that casting, lithium is melted in blanketing with inert gas, and stove and defeated molten metal pipe are to use refractory liner; it is characterized in that: in same crucible (2), adopt conventional melting, refined aluminum; add lithium by proportioning again, feed rare gas element and carry out the founding of purified two-step refining method, refining be cast into the logical in good time protection method of rare gas element of branch.

2, a kind of for realizing the described Al-Li alloy smelting-casting equipment of claim 1, it is characterized in that using a surface to smear the common irony crucible (2) of protective coating, logical rare gas element pipeline (3) and charging opening are arranged on the crucible cover (4), on the material mouth feeding cover (5) is arranged, crucible (2) in the body of heater (1) has been located chute shield cap (6), stove outer protective cover (7), cast alloys chute (8), casting rare gas element pipeline (9), filter screen (10), the stopper (11) of keying cast gate waters material state observation window (12), check casting crystalline hole (13), pouring operation hole (14), water inlet cooled alloy pipe (15), crystallizer (16), casting machine (17), and the surface scribbles the irony instrument vessel of protective coating.

3, smelting-casting equipment according to claim 2 is characterized in that, under the situation of reinforced bore size constancy, the volume of crucible (2) can strengthen as required.