CN100469913C - Liquid state hydrogen-replacing thinning solidifying tissue method in Ti-6Al-4V alloy induction shell smelting process - Google Patents

Abstract

A method for liquid hydrogenation refinement of solidification structure in the process of Ti-6Al-4V alloy induction skull melting relates to a liquid hydrogenation technology in the process of titanium alloy induction skull melting. The method solves the problem of slow speed of hydrogen permeation under titanium alloy atmosphere which is only applicable to the preparation of small specimen or thin specimen, but not to wide production. The detailed procedures of the method are as follows: the charging material of Ti-6Al-4V alloy is put into the crucible of an induction skull melter, heated and melted under the environment of high-purity argon and 400-700Pa pressure; pre-coated bars with the TiH2 of the weight accounting for 0.09 to 0.2 percent of the charging material are added in; when the hydrogen-contained titanium alloy in the crucible cools and the temperature drops below 300 DEG C, the charging material is vented off and cooled until the temperature equal to room temperature. The size of the Ti-6Al-4V alloy crystallization grain after the treatment of liquid hydrogenation with the method is smaller than 800 Mu m. The method is widely applicable in preparation of titanium alloys.

Description

The method that Ti-6Al-4V alloy induction skull melting process liquid state is put the hydrogen thinning solidification structure

Technical field

The present invention relates to titanium alloy induction skull melting process liquid state and put hydrogen technology and a kind of titanium alloy solidified structure thinning method.

Background technology

The Ti-6Al-4V alloy is one of titanium alloy of application quantity maximum, and this alloy can adopt casting and forging method to obtain member.Titanium alloy has higher relatively specific tenacity, and therefore anticorrosive preferably, anti-oxidant, anti-fatigue ability have all obtained extensive application in fields such as Aeronautics and Astronautics, navigation, chemical industry, health care, food and sports.The consumption of titanium alloy working (machining) efficiency very big and that titanium alloy mechanical property characteristics are caused is hanged down and is become current outstanding contradiction.

The first step of the process for processing of Ti-6Al-4V alloy, promptly solidified structure is thicker during casting titanium alloy ingot (foundry goods), and the mechanical property of foundry goods and the properties for follow of ingot casting are had disadvantageous effect.As-cast structure and the processing characteristics of improving titanium alloy for the refinement titanium alloy, usually adopt a kind of method that is called thermo-chemical treatment in the prior art, so-called thermo-chemical treatment is meant is infiltrating a certain amount of hydrogen in solid-state titanium alloy under certain temperature and the nitrogen atmosphere, because the existence of hydrogen makes titanium alloy as cast condition organize refinement to some extent, the plastic forming ability of titanium alloy increases.After realizing above-mentioned purpose, more hydrogenous titanium alloy is carried out vacuum annealing and remove hydrogen, just in the use of titanium alloy, do not have the harm of hydrogen.Thisly generally only be used for handling the less member of wall thickness in solid-state method of infiltrating down hydrogen in titanium alloy, this is because the solid-state hydrogen speed of oozing is slower, needs the long time for big thick member, and have hydrogen skewness phenomenon in member.

Summary of the invention

The objective of the invention is that to ooze hydrogen speed slow in order to solve solid-state down titanium alloy atmosphere, be only applicable to small sample or thin plate sample, the problem that can not be widely used in producing.

The method that Ti-6Al-4V alloy induction skull melting process liquid state of the present invention is put the hydrogen thinning solidification structure is:

Step 1, the furnace charge of Ti-6Al-4V alloy is packed in the crucible 4 of induction skull melting stove;

Step 2, take by weighing the TiH that contains quality of furnace charge described in the step 1 0.09%～0.2% ₂Prefabricated rods 2;

Step 3, the prefabricated rods 2 that step 2 is obtained are anchored on the lower end that is positioned at the feeding rod 1 of crucible 4 tops in the induction skull melting stove;

Step 4, close the door of the melting chamber 3 of induction skull melting stove, be evacuated to 10 ^-1～10 ^-2Pa, the anti-high-purity argon gas that fills be to 300-600Pa, 3 times repeatedly;

High-purity argon gas pressure is at 400～700Pa in step 5, the control melting chamber;

The power supply of the load coil 6 in step 6, the connection induction skull melting stove progressively increases power, improves the temperature of furnace charge in the crucible 4, and the furnace charge in crucible 4 all melts, and is incubated 5～7 minutes then;

Step 7, in molten bath 5, immerse prefabricated rods 2, after prefabricated rods 2 is immersed in the molten bath 5 fully, promote feeding rod 1 immediately, stop heating then;

Step 8, treat in the crucible 4 that furnace charges solidify and are cooled to below 300 ℃, vacuum breaker takes out the furnace charge that has solidified, the room temperature cooling;

Described prefabricated rods 2 is by TiH ₂Powder, Al-85%V master alloy powder and aluminium powder form are formed, described TiH ₂The mass ratio of powder, Al-85%V master alloy powder and aluminium powder form is:

$M_{{\mathrm{TiH}}_2}:M_{\mathrm{Al}-85\%V}:M_{\mathrm{Al}}=10.4:4.7:5.3$ 。

What use among the present invention is induction skull melting stove, its easier stable molten bath 5 that obtains.Induction skull melting technology is used more at the titanium alloy melting casting field at present, it adopts the copper crucible of distinguish to make the furnace charge fusing so that magnetic field affacts metal charge through crucible by Jiao Erre, and alternating magnetic field has stirring action to metal pool simultaneously so that composition and temperature are even.In melting process, exist and the essentially identical scull of charge composition between molten bath and the crucible, melt metal and sidewall of crucible are separated, thereby avoided the pollution of crucible material metal melt.

The present invention adopts in Ti-6Al-4V alloy induction skull melting process by introduce protium in melts of titanium alloy, be that liquid state is put hydrogen, the velocity of diffusion of hydrogen in melt is far longer than the velocity of diffusion in solid, therefore the present invention infiltrates hydrogen in the liquid titanium alloy in the titanium alloy melting process, the solidified structure that the liquid titanium alloy is infiltrated behind the hydrogen has obtained refinement, the average grain size that uses the Ti-6Al-4V alloy material macrostructure that method of the present invention obtains is less than 800 μ m, do not put the primary crystallization average grain size of the Ti-6Al-4V alloy graining tissue of hydrogen and reduced about 47% than carrying out liquid state, this will obviously improve the mechanical property of titanium alloy casting, and the properties for follow of improving titan alloy casting ingot has also been brought into play active effect.

Description of drawings

Fig. 1 is a structural representation of implementing experimental installation induction skull melting stove of the present invention, and wherein 7 is crucible supporting mechanism and circulating water channel; 8 is load coil supporting mechanism and circulating water channel; 9 sculls for the formation of induction melting process; Fig. 2 does not adopt method of the present invention to carry out liquid state to put the macroscopic view of the Ti-6Al-4V alloy of hydrogen and solidify and see that to organize photo, its average grain size be 1072 μ m; Fig. 3 adopts embodiment two described methods to carry out the Ti-6Al-4V alloy macroscopic view solidified structure photo that liquid state is put hydrogen; Fig. 4 adopts embodiment three described methods to carry out the Ti-6Al-4V alloy macroscopic view solidified structure photo that liquid state is put hydrogen; Fig. 5 adopts embodiment four described methods to carry out the Ti-6Al-4V alloy macroscopic view solidified structure photo that liquid state is put hydrogen; Fig. 6 adopts embodiment five described methods to carry out the Ti-6Al-4V alloy macroscopic view solidified structure photo that liquid state is put hydrogen; Fig. 7 is XRD (X-ray diffraction analysis) diffracting spectrum of Ti-6Al-4V alloy, wherein a curve is not adopt method of the present invention to carry out the XRD diffracting spectrum that liquid state is put the Ti-6Al-4V alloy of hydrogen processing, and the b curve is to adopt embodiment five described methods to carry out liquid state to put the XRD diffracting spectrum that hydrogen is handled Ti-6Al-4V alloy afterwards.

Embodiment

Embodiment one: the method that the Ti-6Al-4V alloy induction skull melting process liquid state of present embodiment is put the hydrogen thinning solidification structure is:

Step 1, the furnace charge of Ti-6Al-4V alloy is packed in the crucible 4 of induction skull melting stove;

Step 2, take by weighing the TiH that contains quality of furnace charge described in the step 1 0.09%～0.2% ₂Prefabricated rods 2;

Step 3, the prefabricated rods 2 that step 2 is obtained are anchored on the lower end that is positioned at the feeding rod 1 of crucible 4 tops in the induction skull melting stove;

Step 4, close the door of the melting chamber 3 of induction skull melting stove, be evacuated to 10 ^-1～10 ^-2Pa, the anti-high-purity argon gas that fills be to 300-600Pa, 3 times repeatedly;

High-purity argon gas pressure is at 400～700Pa in step 5, the control melting chamber 3;

The power supply of the load coil 6 in step 6, the connection induction skull melting stove progressively increases power, improves the temperature of furnace charge in the crucible 4, and the furnace charge in crucible 4 all melts, and is incubated 5～7 minutes then;

Step 7, in molten bath 5, immerse prefabricated rods 2, after prefabricated rods 2 is immersed in the molten bath 5 fully, promote feeding rod 1 immediately, stop heating then;

Step 8, treat in the crucible 4 that furnace charges solidify and are cooled to below 300 ℃, vacuum breaker takes out the furnace charge that has solidified, the room temperature cooling.

Porosity in the described prefabricated rods 2 of step 2 is 5～20%, and its moiety is TiH ₂Powder, Al-85%V master alloy powder and aluminium powder form, its making method is: with TiH ₂Powder, Al-85%V master alloy powder and aluminium powder form are in proportion $M_{{\mathrm{TiH}}_2}:M_{\mathrm{Al}-85\%V}:M_{\mathrm{Al}}=10.4:4.7:5.3$ After taking by weighing, mix; Utilizing pressing machine that it is pressed into sectional area is 5～8mm ²Pole or square rod; Be placed in 350 ℃ the vacuum insulation then and carried out vacuum in 10 minutes and take off adsorption treatment, be cooled to room temperature after taking off adsorption treatment.The powder particle diameter of described Al-85%V master alloy powder and aluminium powder form is 10～100 μ m.

TiH in the prefabricated rods 2 for preparing in the present embodiment ₂Content is 52%, can guarantee that the alloying element that prefabricated rods was introduced when liquid state was put hydrogen is identical with the Ti-6Al-4V alloy melt proportioning of furnace charge, and wherein aluminium powder is regulated the prefabricated rods composition on the one hand, plays the binding effect on the one hand in prefabricated rods.

Prefabricated rods 2 immersion process parameters are in step 7: the lowering speed that drops to titanium alloy molten bath 5 liquid levels from hanging position is 200～260cm/min, the speed that prefabricated rods 2 begins to immerse titanium alloy molten bath 5 is 50～80cm/min, i.e. dissolving after described prefabricated rods 2 is immersed in the molten bath 5, the hydrogen that decomposites is dissolved in the melts of titanium alloy; The speed that feeding rod 1 upwards lifts is 300～350cm/min.

After the step 7 in the present embodiment, hydrogenous melts of titanium alloy can be frozen into ingot casting or pour into foundry goods in crucible 4, with convenient follow-up use.

Embodiment two: the difference that present embodiment and embodiment one described Ti-6Al-4V alloy induction skull melting process liquid state are put the method for hydrogen thinning solidification structure is:

The TiH that in the prefabricated rods described in the step 22, contains quality of furnace charge described in the step 1 0.09%～0.11% ₂

In step 6, be heated to furnace charge all after the fusing, continue to be heated to overheated 40 ℃～80 ℃;

In step 7, after prefabricated rods 2 is immersed in the molten bath 5 fully and has promoted feeding rod 1, insulation 60s～90s, and then stop heating.

Referring to Fig. 3, the average grain size of the Ti-6Al-4V alloy material macrostructure that the method for employing present embodiment is prepared is 771 μ m.

Embodiment three: the difference that present embodiment and embodiment one described Ti-6Al-4V alloy induction skull melting process liquid state are put the method for hydrogen thinning solidification structure is:

The TiH that in the prefabricated rods described in the step 22, contains quality of furnace charge described in the step 1 0.12%～0.14% ₂

In step 6, be heated to furnace charge all after the fusing, continue to be heated to overheated 40 ℃～80 ℃;

In step 7, after prefabricated rods 2 is immersed in the molten bath 5 fully and has promoted feeding rod 1, insulation 60s～90s, and then stop heating.

Referring to Fig. 4, the average grain size of the Ti-6Al-4V alloy material macrostructure that the method for employing present embodiment is prepared is 612 μ m.

Embodiment four: the difference that present embodiment and embodiment one described Ti-6Al-4V alloy induction skull melting process liquid state are put the method for hydrogen thinning solidification structure is:

The TiH that in the prefabricated rods described in the step 22, contains quality of furnace charge described in the step 1 0.12%～0.14% ₂

In step 6, be heated to furnace charge all after the fusing, continue to be heated to overheated 40 ℃～80 ℃;

In step 7, after prefabricated rods 2 is immersed in the molten bath 5 fully and has promoted feeding rod 1, insulation 100s～150s, and then stop heating.

Referring to Fig. 5, the average grain size of the Ti-6Al-4V alloy material macrostructure that the method for employing present embodiment is prepared is 610 μ m.

Embodiment five: the difference that present embodiment and embodiment one described Ti-6Al-4V alloy induction skull melting process liquid state are put the method for hydrogen thinning solidification structure is:

The TiH that in the prefabricated rods described in the step 22, contains quality of furnace charge described in the step 1 0.16%～0.18% ₂

In step 6, be heated to furnace charge all after the fusing, continue to be heated to overheated 40 ℃～80 ℃;

In step 7, after prefabricated rods 2 is immersed in the molten bath 5 fully and has promoted feeding rod 1, insulation 100s～150s, and then stop heating.

Referring to Fig. 6, the average grain size of the Ti-6Al-4V alloy material macrostructure that the method for employing present embodiment is prepared is 560 μ m.

Claims (8)

1, the Ti-6Al-4V alloy induction skull melting process liquid state method of putting the hydrogen thinning solidification structure is characterized in that its concrete steps are:

Step 1, the furnace charge of Ti-6Al-4V alloy is packed in the crucible (4) of induction skull melting stove;

Step 2, take by weighing the TiH that contains quality of furnace charge described in the step 1 0.09%～0.2% ₂Prefabricated rods (2);

Step 3, the prefabricated rods (2) that step 2 is obtained are anchored on the lower end that is positioned at the feeding rod (1) of crucible (4) top in the induction skull melting stove;

Step 4, close the door of the melting chamber (3) of induction skull melting stove, be evacuated to 10 ^-1～10 ^-2Pa, the anti-high-purity argon gas that fills be to 300-600Pa, 3 times repeatedly;

Step 5, the interior high-purity argon gas pressure of control melting chamber (3) are at 400～700Pa;

The power supply of the load coil (6) in step 6, the connection induction skull melting stove progressively increases power, improves the temperature of furnace charge in the crucible (4), and the furnace charge in crucible (4) all melts, and is incubated 5～7 minutes then;

Step 7, in molten bath (5), immerse prefabricated rods (2), after prefabricated rods (2) is immersed in the molten bath (5) fully, promote feeding rod (1) immediately, stop heating then;

Step 8, treat that the interior furnace charge of crucible (4) solidifies and is cooled to below 300 ℃, vacuum breaker takes out the furnace charge that has solidified, the room temperature cooling;

Described prefabricated rods (2) is by TiH ₂Powder, Al-85%V master alloy powder and aluminium powder form are formed, described TiH ₂The mass ratio of powder, Al-85%V master alloy powder and aluminium powder form is: M _TiH2:M _Al-85%v: M _Al=10.4:4.7:5.3.

2, the Ti-6Al-4V alloy induction skull melting process liquid state according to claim 1 method of putting the hydrogen thinning solidification structure is characterized in that the porosity 5～20% of described prefabricated rods (2).

3, the Ti-6Al-4V alloy induction skull melting process liquid state according to claim 1 method of putting the hydrogen thinning solidification structure, the powder particle diameter that it is characterized in that described Al-85%V master alloy powder and aluminium powder form is 10～100 μ m.

4, the Ti-6Al-4V alloy induction skull melting process liquid state according to claim 1 method of putting the hydrogen thinning solidification structure, it is characterized in that in step 7, prefabricated rods (2) immerses the process parameter: the lowering speed that drops to titanium alloy molten bath (5) liquid level from hanging position is 200～260cm/min, and the speed that prefabricated rods (2) begins to immerse titanium alloy molten bath (5) is 50～80cm/min; The speed that feeding rod (1) upwards lifts is 300～350cm/min.

5, the Ti-6Al-4V alloy induction skull melting process liquid state according to claim 1 method of putting the hydrogen thinning solidification structure is characterized in that containing the TiH of quality of furnace charge described in the step 1 0.09%～0.11% in the prefabricated rods described in the step 2 (2) ₂

In step 6, be heated to furnace charge all after the fusing, continue to be heated to overheated 40 ℃～80 ℃ after, be incubated 5～7 minutes;

In step 7, after prefabricated rods (2) is immersed in the molten bath (5) fully and has promoted feeding rod (1), insulation 60s～90s, and then stop heating.

6, the Ti-6Al-4V alloy induction skull melting process liquid state according to claim 1 method of putting the hydrogen thinning solidification structure is characterized in that containing the TiH of quality of furnace charge described in the step 1 0.12%～0.14% in the prefabricated rods described in the step 2 (2) ₂

In step 6, be heated to furnace charge all after the fusing, continue to be heated to overheated 40 ℃～80 ℃ after, be incubated 5～7 minutes;

In step 7, after prefabricated rods (2) is immersed in the molten bath (5) fully and has promoted feeding rod (1), insulation 60s～90s, and then stop heating.

7, the Ti-6Al-4V alloy induction skull melting process liquid state according to claim 1 method of putting the hydrogen thinning solidification structure is characterized in that containing the TiH of quality of furnace charge described in the step 1 0.12%～0.14% in the prefabricated rods described in the step 2 (2) ₂

In step 6, be heated to furnace charge all after the fusing, continue to be heated to overheated 40 ℃～80 ℃ after, be incubated 5～7 minutes;

In step 7, after prefabricated rods (2) is immersed in the molten bath (5) fully and has promoted feeding rod (1), insulation 100s～150s, and then stop heating.

8, the Ti-6Al-4V alloy induction skull melting process liquid state according to claim 1 method of putting the hydrogen thinning solidification structure is characterized in that containing the TiH of quality of furnace charge described in the step 1 0.16%～0.18% in the prefabricated rods described in the step 2 (2) ₂

In step 6, be heated to furnace charge all after the fusing, continue to be heated to overheated 40 ℃～80 ℃ after, be incubated 5～7 minutes;

In step 7, after prefabricated rods (2) is immersed in the molten bath (5) fully and has promoted feeding rod (1), insulation 100s～150s, and then stop heating.

Images