CN113333765B - Spray forming and overspray powder collecting method and device - Google Patents

Abstract

The invention relates to a spray forming and over-sprayed powder collecting method and device, and belongs to the technical field of metal spray forming. The invention can quickly and effectively collect the over-sprayed powder in a grading way, thereby enlarging the application range and value of the over-sprayed powder; correspondingly, the device can effectively avoid melt oxidation, further improve the injection quality, and can carry out quick and effective fractional injection and collection on the over-sprayed powder while carrying out injection molding, thereby enlarging the application range and value of the over-sprayed powder. The collecting method comprises the following steps: (a) melt-blowing; (b) filtering and screening; (c) collecting the injection.

Description

Spray forming and overspray powder collecting method and device

Technical Field

The invention relates to a spray forming and over-sprayed powder collecting method and device, and belongs to the technical field of metal spray forming.

Background

Spray forming is to combine atomization of liquid metal and deposition of atomized droplets to produce a dense mass with rapid solidification

A new technique for organizing bulk materials. Has the characteristics of short flow, small product segregation degree and fine grain structure. Is cast with the tradition

Compared with the prior art, the method has obvious economic and technical advantages, and is widely used for developing and developing high-performance materials, such as aluminum alloy and high-temperature titanium

Alloys, metal matrix composites, and the like.

In the prior art, when the alloy liquid in the smelting furnace is transferred into the crucible, the surface alloy liquid is easily oxidized with air

Oxide scale is generated to affect the quality of the spray deposition product, and when the alloy liquid is continuously transferred into the drain ladle, the gold is scooped manually

The efficiency of liquid is low, which affects the production efficiency, and the liquid level in the crucible can not be ensured to affect the spraying effect.

In addition, in the spray forming process of the alloy, the yield of the spray deposition powder is between 70 and 85 percent, and a part of the spray deposition powder is oversprayed

The powder is gathered at the bottom of the deposition chamber, and in the process of recycling the over-sprayed powder, the particle size of the powder is smaller

The oxidation and deterioration may occur in the transfer process, especially the easy oxidation alloy powder such as titanium powder is seriously affected, and the other side is flour

The melt quality is not influenced by the component proportion in the recycling process, and the recycling operation process increases the production period and difficulty.

That is, the prior art has the following problems:

(1) Only the basic process and method of spray deposition are involved, and no attention is paid to melt refinement and melt transfer

And (4) performing protection treatment.

(2) The collection and subsequent treatment of the overspray powder in the prior spray forming technical patent are single, and the overspray powder is subsequently treated

The limitation of use is large.

Disclosure of Invention

The invention aims to provide a spray forming and over-sprayed powder collecting method, which is used for quickly and effectively collecting over-sprayed powder in a grading manner, so that the application range and the value of the over-sprayed powder are expanded; correspondingly, the invention provides a spray forming and overspray powder collecting device which can effectively avoid melt oxidation, further improve the spray quality, and can quickly and effectively perform classified injection and collection on the overspray powder while spray forming, thereby expanding the application range and value of the overspray powder.

The invention relates to a spray forming and over-sprayed powder collecting method, which comprises the following steps:

(a) Melt injection

Atomizing the smelted molten metal into a deposition chamber in a vacuum state, and spraying a part of the molten metal to the deposition disc

Forming a spray forming body, and forming overspray powder from the other part of the metal liquid;

(b) Filtering and screening

Screening and grading the overspray powder under a vacuum closed condition;

(c) Collection by injection

And mixing the binder with the graded overspray powder under the condition of protective gas.

Preferably, in step (c), the classified overspray powder can be directly packaged in a vacuum sealing mode without injection collection.

For the metal powder with weak oxidation degree, the metal powder can be directly packaged in a vacuum sealing way after being sieved in a grading way.

The invention relates to a device for realizing spray forming and over-sprayed powder collecting methods, which comprises the following steps: the bottom of the heat-preservation crucible is provided with a flow guide pipe, and the top of the heat-preservation crucible is provided with a sealing cover; the feeding mechanism is communicated with the heat-insulating crucible and is used for feeding materials to the heat-insulating crucible; the atomizer is connected to the tail end of the flow guide pipe; the deposition chamber is arranged at the outlet end of the atomizer, a deposition disc is arranged in the deposition chamber, a discharge channel is arranged at the bottom of the deposition chamber, and a vacuumizing tube is connected to the discharge channel; the screening bin is hermetically connected with the discharge channel; the screen is obliquely fixed on the inner wall of the screening bin; the first discharge pipe is arranged below the screen; a second discharge pipe arranged at the lower end of the screen mesh; and the powder mixing mechanism is hermetically connected with the first discharge pipe and the second discharge pipe respectively.

Preferably, the powder mixing mechanism comprises a first powder collecting box hermetically connected with the first discharge pipe; the second powder collecting box is hermetically connected with the second discharge port pipe; the first binder containing box is arranged on one side of the first powder collecting box; the second binder containing box is arranged on one side of the second powder collecting box; the first forming bin is hermetically connected with the first powder collecting box and the first binder containing box; the second forming bin is hermetically connected with the second powder collecting box and the second binder containing box; the first binder holds the case and the second binder holds and all is equipped with the protection gas and inserts the pipe on the case.

Preferably, the first powder collecting box and the first binder containing box are connected with the first forming bin in a sealing mode through connecting pipes, the second powder collecting box and the second binder containing box are connected with the second forming bin in a sealing mode through connecting pipes, and flow control valves are arranged on the four connecting pipes.

The protective gas is respectively introduced into the binders of the first binder containing box and the second binder containing box through the protective gas access pipe, so that air is prevented from entering the forming bin along with the binders to pollute the powder, powder spraying and quantitative mixing of the binders are realized by controlling a flow valve on the connecting pipe, and finally injection and collection of the over-sprayed powder are realized in the forming bin.

Preferably, the feeding mechanism comprises a smelting crucible, a cover plate and a protective gas tank body which are hermetically connected to the top of the smelting crucible, the protective gas tank body is communicated with the smelting crucible through a pipeline, and the smelting crucible is communicated with the heat-insulating crucible through a communicating pipe.

When the device works, the metal liquid in the melting crucible flows into the heat-insulating crucible through the communicating pipe under the pressure action of the protective gas in the protective gas tank, the protective gas effectively avoids melt oxidation, and the pressure regulating valve can be arranged to regulate the liquid level in the heat-insulating crucible.

Preferably, a vibration motor is arranged on the screening bin.

Under vibrating motor's effect, the powder that gets into the screening storehouse can be according to the particle diameter quick grading, and the powder that the particle diameter is less than the screen cloth aperture falls into first discharging pipe, and the powder that the particle diameter is greater than the screen cloth aperture gets into the second discharging pipe along the slope screen cloth.

Preferably, a filter plate is horizontally arranged in the heat-insulating crucible. The filter can filter the cinder and the metal residue that probably exists in the metal liquid, guarantees product quality to the honeycomb duct jam can be avoided to clean no foreign matter's fuse-element, improves and sprays formed body quality and improves production efficiency. The filter can be ceramic material, can select single-layer or multilayer filter according to the solution kind.

Preferably, the periphery of the heat-insulating crucible is provided with a heat-insulating layer.

Preferably, a grid is arranged in the discharge channel.

The working principle and the using process are as follows:

putting metal raw materials into a melting crucible for melting, and electromagnetically stirring the melt to ensure uniform components for the purpose of ensuring

The superheat degree of the melt can be adjusted according to the metal type to verify the quality of the injection molding body. Before the start of injection, the injection distance is adjusted to

300-500mm and the diameter of the draft tube is 3-10 mm; vacuumizing the jet deposition chamber, and heating and insulating the heat-insulating crucible and the filter plate at a temperature not lower than the melting point of the metal; after the metal liquid is smelted, introducing nitrogen or inert gas into the smelting crucible by the protective gas tank body, and allowing the metal liquid in the smelting crucible to enter the heat-insulating crucible through the communicating pipe under the action of gas pressure; the outer sides of the communicating pipe and the heat-preserving crucible are packaged by heat-preserving and heat-insulating materials.

After the spraying is started, the temperature of the atomizing gas is normal temperature, the pressure is 0.5-1.2 MPa, the flow rate of the metal liquid in the heat-insulating crucible is 7-15 kg/min, along with the start of the spraying forming, a part of the metal liquid is sprayed and deposited on a deposition disc under the action of an atomizer to form a spraying forming body, the other part of the metal liquid becomes over-sprayed powder and falls into the bottom of a deposition chamber, and flaky and blocky solids mixed in the powder enter a screening bin after being filtered by grids. The aperture of the screen mesh is 30 mu m, the powder on the screen mesh is classified and sieved under the vibration action of the vibration motor, the powder with the particle size smaller than the aperture of the screen mesh enters the first powder collecting box, and the powder with the particle size larger than the aperture of the screen mesh enters the second powder collecting box. When powder in the powder collection box is injected and collected, a proper binder is selected according to the type of metal powder, and protective gas is introduced into the binder containing box, so that the powder can be prevented from being polluted by air along with the binder; then quantitative mixing is realized by controlling the flow control valves on the connecting pipes of the powder collecting box and the binder containing box, and finally sealed collection is realized in the forming bin.

The invention has the beneficial effects that: through setting up feeding mechanism, effectively avoid the fuse-element oxidation, further improve injection quality, mix powder mechanism through the setting and spray when taking shape, can carry out quick effectual hierarchical injection to the powder of spraying and collect, enlarged the application scope and the value of the powder of spraying.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment;

FIG. 2 is a metallographic structure diagram of a spray formed body;

FIG. 3 is a macro-morphogram of over-sprayed powder before sieving;

FIG. 4 shows a first microstructure after sieving with a powder-spraying sieve;

FIG. 5 is a second microstructure after sieving with a powder-spraying sieve;

in the figure: 1. a heat preservation crucible; 2. a flow guide pipe; 3. a sealing cover; 4. an atomizer; 5. a deposition chamber; 6. a deposition tray; 7.

a discharge channel; 8. vacuumizing a tube; 9. screening the bin; 10. screening a screen; 11. a first discharge pipe; 12. a second discharge pipe; 13.

a first dust collecting box; 14. a second powder collecting box; 15. a first binder holding tank; 16. a second binder holding tank; 17. first of all

A forming bin; 18. a second forming bin; 19. a shielding gas access pipe; 20. a connecting pipe; 21. a flow control valve; 22. smelting a crucible; 23. a cover plate; 24. a protective gas tank body; 25. a communicating pipe; 26. a vibration motor; 27. a filter plate; 28. a heat-insulating layer; 29. a grid.

Detailed Description

The invention will be further described with reference to the accompanying drawings.

The spray forming and overspray powder collecting method provided by the invention comprises the following steps:

(a) Melt injection

Atomizing the smelted molten metal into a deposition chamber in a vacuum state, and spraying a part of molten metal to the deposition disc

Forming a spray forming body, and forming overspray powder by the other part of the metal liquid;

(b) Filtering and screening

Screening and grading the over-sprayed powder under a vacuum closed condition;

(c) Collection by injection

And mixing the binder with the classified overspray powder under the condition of protective gas.

As shown in fig. 1-5, the apparatus for implementing the above method according to the present invention includes: the bottom of the heat-preservation crucible 1 is provided with a flow guide pipe 2, and the top of the heat-preservation crucible is provided with a sealing cover 3; the feeding mechanism is communicated with the heat-insulating crucible 1 and is used for feeding materials to the heat-insulating crucible 1; the atomizer 4 is connected to the tail end of the draft tube 2; a deposition chamber 5 arranged at the outlet end of the atomizer 4, wherein a deposition disc 6 is arranged in the deposition chamber, a discharge channel 7 is arranged at the bottom of the deposition chamber, and a vacuumizing pipe 8 is connected on the discharging channel; the screening bin 9 is hermetically connected with the discharge channel 7; the screen 10 is obliquely fixed on the inner wall of the screening bin 9; a first discharge pipe 11 disposed below the screen mesh 10; a second discharge pipe 12 arranged at the lower end of the sieve screen 10; and a powder mixing mechanism hermetically connected with the first discharge pipe 11 and the second discharge pipe 12 respectively. The powder mixing mechanism comprises a first powder collecting box 13 hermetically connected with the first discharge pipe 11; a second dust collecting box 14 hermetically connected to the second discharge pipe 12; a first binder storage tank 15 provided on one side of the first dust collection tank 13; a second binder storage tank 16 provided on one side of the second powder collection tank 14; a first forming chamber 17 hermetically connected to the first powder collecting tank 13 and the first binder containing tank 15; and a second forming chamber 18 hermetically connected to the second dust collecting tank 14 and the second binder containing tank 16; and the first adhesive containing box 15 and the second adhesive containing box 16 are both provided with a protective gas access pipe 19. First album of powder case 13 and first binder hold case 15 and all pass through connecting pipe 20 and first shaping storehouse 17 sealing connection, second album of powder case 14 and second binder hold case 16 and all pass through connecting pipe 20 and second shaping storehouse 18 sealing connection, be equipped with flow control valve 21 on four connecting pipes 20. The feeding mechanism comprises a smelting crucible 22, a cover plate 23 and a protective gas tank 24 which are connected to the top of the smelting crucible 22 in a sealing mode, the protective gas tank 24 is communicated with the smelting crucible 22 through a pipeline, and the smelting crucible 22 is communicated with the heat-insulating crucible 1 through a communicating pipe 25. And a vibration motor 26 is arranged on the screening bin 9. A filter plate 27 is horizontally arranged in the heat-insulating crucible 1. An insulating layer 28 is arranged on the periphery of the insulating crucible 1. A grid 29 is arranged in the discharging channel 7.

In the embodiment, al-Zn-Mg-Cu series high-strength aluminum alloy is selected, and the alloy elements comprise the following components in percentage by mass: 11 to 13 percent of Zn, 2.2 to 2.4 percent of Mg, 1.0 to 1.2 percent of Cu, 0.142 percent of Mn, 0.052 percent of Fe, 0.045 percent of Si, 0.205 percent of Zr, 0.094 percent of Ni, less than or equal to 0.002 percent of Cr, less than or equal to 0.002 percent of Ti, and the balance of Al.

The melting temperature of the alloy is between 850 ℃ and 900 ℃, molten aluminum in a melting crucible enters a heat-preservation crucible under the gas pressure of a protective gas tank body after being refined by electromagnetic stirring and the like, and a spray forming body and overspray powder are obtained by spray forming; the spray forming process parameters are as follows: the atomization air pressure is 0.5-1.2 MPa, the flow rate of the metal liquid in the heat-insulating crucible is 7-15 kg/min, the spraying distance is 300-500mm, the diameter of the guide pipe is 3-10 mm, and the rotating speed of the deposition disc is 30-70 rpm; the adhesive is paraffin wax flux.

After the spray molded body was removed from the deposition plate, microstructure testing was performed by an Axio Imager M2M zeiss optical microscope and the grain size was tested using Axio vision software. As shown in FIG. 2, the average grain size was 45 μm as measured by the grain size in the metallographic photographs, and the grain morphology of the spray-molded article of the present invention had good uniformity of structure, and no significant macro-voids appeared although some voids appeared in the grain boundaries. FIG. 3 is a macroscopic morphology diagram of the overspray powder; fig. 4 and 5 are microstructure diagrams of metal powder in the first powder collecting tank and the second powder collecting tank, respectively.

The use process of the invention is as follows: the method comprises the following steps of putting a metal raw material into a melting crucible for melting, introducing nitrogen or inert gas into the melting crucible by a protective gas tank body after the metal liquid is melted, and allowing the metal liquid in the melting crucible to enter a heat-insulating crucible through a communicating pipe under the action of gas pressure. After the spraying is started, a part of the metal liquid is sprayed and deposited on the deposition disc under the action of the atomizer to form a spraying formed body, the other part of the metal liquid becomes over-sprayed powder and falls into the bottom of the deposition chamber, and flaky and blocky solids mixed in the powder enter the screening bin after being filtered by the grids. Powder on the screen mesh is sieved in grades under the vibration of the vibrating motor, powder with the particle size smaller than the aperture of the screen mesh enters the first powder collecting box, and powder with the particle size larger than the aperture of the screen mesh enters the second powder collecting box. When powder in the powder collection box is injected and collected, a proper binder is selected according to the type of metal powder, and protective gas is introduced into the binder containing box, so that the powder can be prevented from being polluted by air along with the binder; then quantitative mixing is realized by controlling the flow control valves on the connecting pipes of the powder collecting box and the binder containing box, and finally sealed collection is realized in the forming bin.

Of course, the foregoing is merely exemplary of the invention and is not to be construed as limiting the scope of the embodiments of the invention. The present invention is not limited to the above examples, and equivalent changes and modifications made by those skilled in the art within the spirit and scope of the present invention should be construed as being included in the scope of the present invention.

Claims (8)

1. A spray forming and overspray powder collecting device is characterized by comprising:

the bottom of the heat-preservation crucible (1) is provided with a flow guide pipe (2), and the top of the heat-preservation crucible is provided with a sealing cover (3);

the feeding mechanism is communicated with the heat-insulating crucible (1) and is used for feeding materials to the heat-insulating crucible (1);

an atomizer (4) connected to the end of the draft tube (2);

a deposition chamber (5) arranged at the outlet end of the atomizer (4), a deposition disc (6) is arranged in the deposition chamber, a discharge channel (7) is arranged at the bottom of the deposition chamber,

a vacuum-pumping pipe (8) is connected on the upper part;

a screening bin (9) hermetically connected with the discharge channel (7);

a screen (10) obliquely fixed on the inner wall of the screening bin (9);

a first discharge pipe (11) arranged below the screen (10);

a second discharge pipe (12) arranged at the lower end of the sieve (10);

and a powder mixing mechanism which is hermetically connected with the first discharging pipe (11) and the second discharging pipe (12) respectively; the powder mixing mechanism comprises a powder mixing mechanism,

a first powder collecting box (13) hermetically connected with the first discharging pipe (11);

a second powder collecting box (14) hermetically connected with the second discharge pipe (12);

a first binder containing box (15) arranged on one side of the first powder collecting box (13);

a second binder containing box (16) arranged on one side of the second powder collecting box (14);

a first forming bin (17) hermetically connected with the first powder collecting box (13) and the first binder containing box (15);

and a second forming bin (18) hermetically connected with the second powder collecting tank (14) and the second binder containing tank (16);

the first binder containing box (15) and the second binder containing box (16) are both provided with a protective gas access pipe (19);

first album of powder case (13) and first binder hold case (15) and all pass through connecting pipe (20) and first shaping storehouse (17) sealing connection, second album of powder case (14) and second binder hold case (16) and all pass through connecting pipe (20) and second shaping storehouse (18) sealing connection, all be equipped with flow control valve (21) on connecting pipe (20).

2. The spray-formed, overspray powder collection apparatus of claim 1, wherein: the feeding mechanism comprises a smelting crucible (22), a cover plate (23) and a protective gas tank body (24) which are connected to the top of the smelting crucible (22) in a sealing mode, the protective gas tank body (24) is communicated with the smelting crucible (22) through a pipeline, and the smelting crucible (22) is communicated with the heat-insulating crucible (1) through a communicating pipe (25).

3. A spray-forming, overspray powder collection apparatus as defined in claim 2, wherein: and a vibration motor (26) is arranged on the screening bin (9).

4. A spray-forming, overspray powder collection apparatus as defined in claim 2, wherein: a filter plate (27) is horizontally arranged in the heat-preservation crucible (1).

5. A spray formed, overspray powder collection apparatus as defined in claim 2, wherein: and a heat-insulating layer (28) is arranged on the periphery of the heat-insulating crucible (1).

6. A spray-forming, overspray powder collection apparatus as defined in claim 2, wherein: a grid (29) is arranged in the discharging channel (7).

7. A spray forming overspray powder collection method using the spray forming overspray powder collection apparatus of any of claims 1 to 6, wherein the spray forming overspray powder collection method comprises the steps of:

(a) Melt injection

Atomizing and spraying the smelted molten metal into a deposition chamber in a vacuum state, spraying a part of molten metal to a deposition plate to form a spray forming body, and forming overspray powder by the other part of molten metal;

(b) Filtering and screening

Screening and grading the over-sprayed powder under a vacuum closed condition;

(c) Collection by injection

And mixing the binder with the graded overspray powder under the condition of protective gas.

8. The spray-formed, overspray powder collection method of claim 7, wherein: in the step (c), the graded overspray powder is directly packaged in a vacuum sealing way without injection and collection.

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