CN106834760B - A kind of vacuum smelting method of Intermatallic Ti-Al compound - Google Patents

Abstract

The invention discloses a kind of vacuum smelting methods of Intermatallic Ti-Al compound; including selecting raw material; it is separately added into crucible and secondary charging bucket; the first inert gas tube and the second inert gas tube progress Argon on sidewall of crucible are utilized after heating; select different Argon opportunitys and pressure; ensure temperature in crucible in the early stage; rapid melting; ensure to be formed in formation air curtain wall at sidewall of crucible after complete melting; it protects it from reacting with aluminium alloy, forms stirring after trace element is added, its mixing is made to melt; so that aluminium alloy is stablized in cast, prevents volume gas and turbulent flow.

Description

A kind of vacuum smelting method of Intermatallic Ti-Al compound

Technical field

The invention belongs to materials processing technology fields, more particularly, to a kind of vacuum melting side of Intermatallic Ti-Al compound Method.

Background technology

Intermatallic Ti-Al compound density is small, and intensity is big, hardness is big, and high temperature resistance is strong, corrosion resistance and antifriction It is high to wipe performance, especially TiAl intermetallic compound is because having high specific strength, high specific stiffness, anti-corrosion, wear-resisting, high temperature resistant and excellent The advantages that different antioxygenic property, is becoming the good candidates structural wood in the fields such as contemporary aerospace industry, civilian industry One of material, especially has broad application prospects in blade of aviation engine field.3D printing or increasing material manufacturing are as close A kind of quick shaping process risen over year, using successively powdering, laser or electron beam melt molding mode, realize precision The finishing of component is molded, and the defects of avoid the shrinkage cavity shrinkage porosity of casting process appearance, is become a kind of emerging material and is added Work means.

Powder used in 3D printing at present, generally by vacuum pouring after melting at ingot casting, subsequent secondary smelting simultaneously uses The mode of atomization legal system powder obtains, and in vacuum melting and casting process, ensure the degree of purity of alloy melt, for subsequently making Properties of product during powder or even 3D printing are most important, and presently used vacuum melting generally passes through the crucible in induction furnace The mode that Dumpage type is poured into a mould after middle carry out vacuum induction melting, but the reactivity of Intermatallic Ti-Al compound in the liquid state is non- Chang Gao is easy to react with alumina crucible, brings field trash into and the oxygen content of melt is made to increase, shadow is caused to performance It rings.

Invention content

In order to solve the above technical problems, the present invention provides a kind of vacuum melting cast sides of Intermatallic Ti-Al compound Method improves degree of purity by the way of Argon step by step.

The complete technical solution of the present invention includes：

A kind of vacuum smelting method of Intermatallic Ti-Al compound, which is characterized in that include the following steps：

1) select the raw material of the Intermatallic Ti-Al compound component of wanted melting, including titanium sponge, aluminium block micro with remaining Element；

2) titanium sponge and part aluminium block are put into the crucible of vacuum induction melting furnace, remaining aluminium block is put into middle secondary charging In first feed bin of bucket, remaining trace element is put into second feed bin of secondary charging bucket；On crucible wall from bottom to top It is connected separately with the first inert gas tube and the second inert gas tube, the first inert gas tube and the second inert gas tube are two Root is distributed in crucible both sides, is surrounded by the metal probe of refractory material casing in the inert gas tube equipped with two outsides,

3) bell is covered, sealing vacuumizes, and opens induction heating apparatus and is heated；After the Melt molten of part, melt arrives When up to inert gas nozzle, contacting metal probe makes two metal probe forming circuits, control system control flow valve start to blow Argon；Specific maximum pressure value P is determined according to the specific location of inert gas tube_max, Argon is determined according to the speed of specific melting The argon gas rate of rise, specially molten metal contacts to probe when start to boost, uniformly increase to 0.9Pmax in 5min or so；

4) after the metal in crucible is completely melt, in certain temperature held for some time, secondary charging bucket is then overturn First feed bin makes remaining aluminium block enter melt, continues held for some time, overturns the second feed bin of secondary charging bucket, makes remaining Trace element enter melt, while Argon pressure value is increased to Pmax, continues thereafter with held for some time；

5) inert gas tube Argon pressure value is reduced to 0.8-0.9Pmax, held for some time, then cast is cast Ingot.

It includes Al that the alloy compositions, which are by atomic percent,：39-40%, Cr：1.2-1.5-%, Nb：1.6- 1.8%, Si：0.05-0.11%, Mo：0.2-0.3%, V：2.2-2.8%, B：0.03-0.04%, La：0.02-0.04%, it is remaining Amount is Ti.

Maximum pressure value in first inert gas tube and the second inert gas tube calculates as follows：

P_max=A ρ_TigH_i

In formula, Pmax is the inert gas maximum pressure value at this, ρ_TiFor the Intermatallic Ti-Al compound density of institute's melting, G is acceleration of gravity, H_iDistance for i-th of pipeline apart from crucible surface, A are the correction factor that value range is 1.2-1.5.

The present invention compared with the existing technology the advantages of be：

1. by being blown into inert gas, air curtain wall is formed at crucible wall surface, reduces connecing for aluminium alloy and sidewall of crucible It touches, the extent of reaction of Intermatallic Ti-Al compound liquid and crucible, simultaneous selection different Argon opportunity and pressure is reduced, first Phase ensures that temperature in crucible, rapid melting ensure to be formed at sidewall of crucible formation air curtain wall after complete melting, protect it from Aluminium alloy reacts, and stirring is formed after trace element is added, its mixing is made to melt, and so that aluminium alloy is stablized in cast, prevents from rolling up Gas and turbulent flow.

Specific implementation mode

The present invention will be further described With reference to embodiment.

The alloy compositions selected is include Al by atomic percent：39-40%, Cr：1.2-1.5-%, Nb：1.6- 1.8%, Si：0.05-0.11%, Mo：0.2-0.3%, V：2.2-2.8%, B：0.03-0.04%, La：0.02-0.04%, it is remaining Amount is Ti.

The titanium sponge that corresponding mass part is selected after mass percent is converted into according to said components, it is clear using acetone ultrasonic wave 10-15min is washed, the Al blocks of corresponding mass part is cut, surface and oil contaminant is cleaned after polishing off surface film oxide, remaining is each micro Elemental constituent is spare after being weighed,

The aluminium block of titanium sponge and 1/4 is put into the crucible of vacuum induction melting furnace, has secondary charging bucket above crucible, it should Secondary charging bucket includes two feed bins, and during remaining aluminium block is put into first feed bin, remaining trace element is put into second material In storehouse.

The first inert gas tube and the second inert gas tube, the first indifferent gas are connected separately on crucible wall from bottom to top Body pipe and the second inert gas tube are two, are distributed in crucible both sides, are surrounded by equipped with two outsides in the inert gas tube The metal probe of refractory material casing, the metal probe front end are mutually not in contact with each other at a distance of about 0.5-1cm, rear end connection Control system；

Bell is then covered, sealing is evacuated down to 10^-5-10^-6Pa opens induction heating apparatus and is heated, heating power For 250-300KW, aluminium in crucible is first begin to melt since fusing point is relatively low, and the molten aluminum of fusing forms molten bath and surrounds titanium sponge, And react with titanium, the fusing of titanium is accelerated, when melt reaches inert gas nozzle, contacting metal probe makes two gold Belong to probe forming circuit, control system control flow valve starts Argon, in the first inert gas tube and the second inert gas tube Maximum pressure value calculates as follows：

P_max=A ρ_TigH_i

In formula, Pmax is the inert gas maximum pressure value at this, ρ_TiFor the Intermatallic Ti-Al compound density of institute's melting, G is acceleration of gravity, H_iDistance for i-th of pipeline apart from crucible surface, A are the correction factor that value range is 1.2-1.5.

Determine the argon gas rate of rise of Argon according to the speed of specific melting, specially molten metal contacts to probe when start Boosting, uniformly increases to 0.9Pmax in 5min or so, hereafter remains unchanged, be due to melting initial stage metal using aforesaid way Not all fusings, the static pressure of melt is little, while preventing Argon amount excessive at the beginning from can so that temperature declined in crucible Greatly, smelting efficiency is influenced.

After metal in crucible is completely melt, 3-5min is kept the temperature at 1700 DEG C, then overturns the first material of secondary charging bucket Storehouse makes remaining aluminium block enter melt, after continuing melting heat preservation 5min, overturns the second feed bin of secondary charging bucket, keeps remaining micro- Secondary element enters melt, and Argon pressure value is increased to Pmax, continue thereafter with heat preservation melting 5min, using secondary charging mode be because If to be initially added trace alloying element, the evaporation capacity of trace element can be caused excessive by long-time melting, at sub-control Make existing deviation.The argon pressure being blown at this time reaches maximum value, in addition to entering in aluminium alloy, is formed at crucible wall surface Air curtain wall reduces contact of the aluminium alloy with sidewall of crucible, reduce Intermatallic Ti-Al compound liquid and crucible the extent of reaction it Outside, high pressure values also make argon gas enters inside aluminium alloy to be stirred simultaneously, make the trace alloying element of wherein secondary charging It is sufficiently mixed uniformly.

After melting, inert gas tube Argon pressure value is reduced to 0.8-0.9Pmax, with quiet with the aluminium alloy at this Pressure maintains balance to be advisable, and keeps the temperature 1-2min, so that the bubble in melt is escaped, and keep aluminium alloy steady, and then cast is cast Ingot.

The above is only presently preferred embodiments of the present invention, is not imposed any restrictions to the present invention, every according to the present invention Technical spirit changes any simple modification, change and equivalent structure made by above example, still falls within skill of the present invention In the protection domain of art scheme.

Claims (4)

1. a kind of vacuum smelting method of Intermatallic Ti-Al compound, which is characterized in that include the following steps：

1) raw material of the Intermatallic Ti-Al compound component of wanted melting, including titanium sponge, aluminium block and remaining trace element are selected；

2) titanium sponge and part aluminium block are put into the crucible of vacuum induction melting furnace, remaining aluminium block is put into middle secondary charging bucket In first feed bin, remaining trace element is put into second feed bin of secondary charging bucket；Distinguish from bottom to top on crucible wall It is connected with the first inert gas tube and the second inert gas tube, the first inert gas tube and the second inert gas tube are two, Crucible both sides are distributed in, are surrounded by the metal probe of refractory material casing in the inert gas tube equipped with two outsides；

3) bell is covered, sealing vacuumizes, and opens induction heating apparatus and is heated；After the Melt molten of part, melt reaches lazy Property gas nozzle when, contacting metal probe makes two metal probes forming circuit, control system control flow valve start Argon； The maximum pressure value Pmax that Argon is determined according to the specific location of inert gas tube determines Argon according to the speed of specific melting The argon gas rate of rise；

4) after the metal in crucible is completely melt, in certain temperature held for some time, the first of secondary charging bucket is then overturn Feed bin makes remaining aluminium block enter melt, continues held for some time, overturns the second feed bin of secondary charging bucket, keeps remaining micro- Secondary element enters melt, while Argon pressure value is increased to Pmax, continues thereafter with held for some time；

5) inert gas tube Argon pressure value is reduced to 0.8-0.9Pmax, held for some time, then cast obtains ingot casting.

2. method described in claim 1, which is characterized in that it includes Al that the alloy compositions, which are by atomic percent,：39- 40%, Cr：1.2-1.5-%, Nb：1.6-1.8%, Si：0.05-0.11%, Mo：0.2-0.3%, V：2.2-2.8%, B： 0.03-0.04%, La：0.02-0.04%, surplus Ti.

3. method described in claim 1, which is characterized in that in first inert gas tube and the second inert gas tube Maximum pressure value calculates as follows：

P_max=A ρ_TigH_i

In formula, Pmax is the inert gas maximum pressure value at this, ρ_TiFor the Intermatallic Ti-Al compound density of institute's melting, g is Acceleration of gravity, H_iDistance for i-th of pipeline apart from crucible surface, A are the correction factor that value range is 1.2-1.5.

4. method described in claim 1, which is characterized in that in step 3 rate of rise be specially molten metal contacts to probe when Start to boost, uniformly increases to 0.9Pmax. in 5min or so.