CN116197404A - Melting crucible and flipping pouring melting system for vacuum air atomization pulverization - Google Patents

Abstract

The invention discloses a smelting crucible and a turnover pouring smelting system for vacuum gas atomization powder preparation, wherein the smelting crucible comprises a crucible body and a heat insulation lining, an annular groove is formed in the inner wall of the heat insulation lining along the circumferential direction, a plurality of balls distributed along the circumferential direction of the annular groove are arranged in the annular groove, the crucible body is arranged in the heat insulation lining, the outer wall of the crucible body is abutted against the balls, and the crucible body can rotate relative to the heat insulation lining. When the smelting crucible is used for casting the metal melt, the crucible body automatically rotates along with the pouring of the smelting crucible, so that the pouring gate is always positioned below, the position of the metal melt relative to the pouring opening of the tundish is ensured to be unchanged, the liquid injection of the metal melt is always positioned on the same straight line with the central axis of the tundish in the casting process, the metal melt is prevented from splashing on the inner wall of the tundish or the position with lower temperature such as the ceramic pouring gate, and the like, so that the superheat loss is avoided, the atomization liquid guide tube is blocked, or the fine powder rate of gas atomization powder preparation is reduced.

Description

Melting crucible and flip casting melting system for vacuum air atomization pulverization

technical field

The invention relates to the technical field of vacuum air atomization powder making, in particular to a smelting crucible and an inverted pouring melting system for vacuum air atomization powder making.

Background technique

In recent years, with the continuous development of metal additive manufacturing technology, it has been widely used in many fields such as aerospace, medical, mold and automobile manufacturing. At present, the main technical route for preparing metal powder raw materials for additive manufacturing is vacuum air electrode induction gas atomization (VIGA). VIGA uses high-pressure argon to break and solidify the metal melt in the crucible into metal powder.

In the gas atomization process, in addition to the gas atomization nozzle, the alloy melting system plays a key role. The smelting system of industrial-grade gas atomization pulverization is usually realized by flip casting. The metal melt from the melting crucible is poured into the tundish by inverted casting. Since the position of the pouring port of the metal melt relative to the tundish changes during the turning process of the smelting crucible, part of the melt will fall on the lower middle and upper part of the tundish, resulting in a loss of superheat and thus affecting the yield of the powder .

Contents of the invention

The technical problem to be solved by the present invention is to provide a smelting crucible and an inverted pouring smelting system for vacuum air atomization pulverization in order to overcome the defects in the prior art.

The present invention solves the above technical problems through the following technical solutions:

The invention provides a smelting crucible, which comprises a crucible body and a heat insulating liner, an annular groove is arranged on the inner wall of the heat insulating liner along the circumferential direction, and a plurality of The crucible body is arranged in the heat-insulating liner, the outer wall of the crucible body is in contact with the ball and the crucible body can rotate relative to the heat-insulation liner.

In this scheme, the melting crucible adopts the above-mentioned structure. When pouring the metal melt, the crucible body will automatically rotate with the pouring of the melting crucible, so that the gate is always at the bottom to ensure that the metal melt is relatively close to the pouring port of the tundish. The position remains unchanged, so that the liquid injection of the metal melt is always on the same line as the central axis of the tundish during the casting process, so as to prevent the metal melt from splashing on the inner wall of the tundish or the ceramic sprue where the temperature is lower, causing excessive The loss of heat will lead to blockage of the atomization catheter, or reduce the fine powder rate of gas atomization powder making.

Preferably, the crucible body includes a melting inner crucible and a heat-insulating outer crucible, the melting inner crucible is arranged inside the heat-insulating outer crucible and is relatively fixed, and the outer surface of the heat-insulating outer crucible is in contact with the ball Abut.

In this solution, the crucible body is provided with a heat-insulating outer crucible to insulate the melting inner crucible, so as to avoid the influence of the temperature drop of the metal melt on the fine powder rate of gas atomization powder making.

Preferably, fused magnesia is filled between the melting inner crucible and the heat-insulating outer crucible.

In this solution, by filling the space between the melting inner crucible and the heat-insulating outer crucible with fused magnesia, the two can be relatively fixed and the relative movement of the two can be avoided.

Preferably, there are multiple annular grooves;

And/or, the annular groove is circular.

In this solution, the above-mentioned structure can make the rotation between the crucible body and the heat insulating liner more stable, and no rotation deviation will affect the pouring of the metal melt.

Preferably, the heat insulating bushing is made of ceramic material;

And/or, the balls are spherical pure zirconia ceramic balls.

Preferably, the two balls in the annular groove are in contact with each other.

The present invention also provides an inversion pouring melting system for vacuum air atomization pulverization, the inversion pouring melting system includes the above-mentioned melting crucible.

Preferably, the inverted pouring melting system further includes an induction coil, and the induction coil is arranged on the outer wall of the heat insulation bushing.

Preferably, the induction coil and the heat insulation bushing are relatively fixed through refractory cement.

Preferably, the inverted pouring melting system further includes an arc-shaped slide rail, a slider is provided on the bottom of the crucible body, and the slider is slidingly matched with the arc-shaped slide rail; the arc-shaped slide rail is set The sprue of the crucible body is turned downward when the slider slides from bottom to top along the arc-shaped slide rail.

In this solution, the above-mentioned structure can be used to better control the turning of the melting crucible, so that the gate of the melting crucible can be turned downward along a predetermined track, so that the metal melt can be smoothly poured into the tundish.

Preferably, the overturning pouring melting system further includes a rotating arm connected to the heat insulation bushing, and the rotating arm is used to drive the melting crucible along the preset track of the arc slide rail turn.

Preferably, the inverted pouring smelting system further includes a tundish, the tundish is arranged on the side of the crucible body whose opening is turned downward;

The tundish includes a tundish body made of graphite, the inner wall of the tundish body is coated with a refractory mortar layer, and the refractory mortar layer includes 85% magnesium oxide and 15% aluminum borate by weight.

Preferably, the thickness of the refractory cement layer is 8-10mm.

Preferably, the inner wall of the refractory mortar layer is coated with a magnesium oxide coating, and the magnesium oxide coating is mixed with liquid sodium silicate and evenly coated on the inner wall of the refractory mortar layer.

The positive progress effect of the present invention is that: when the melting crucible of the present invention is pouring the metal melt, the crucible body will automatically rotate with the pouring of the melting crucible, so that the gate is always at the bottom, ensuring the metal melt relative to the tundish. The position of the pouring port remains unchanged, so that the liquid injection of the metal melt is always on the same line as the central axis of the tundish during the casting process, so as to prevent the metal melt from splashing on the inner wall of the tundish or the ceramic gate, etc., where the temperature is lower. Cause the loss of superheat, lead to blockage of the atomization catheter, or reduce the fine powder rate of gas atomization pulverization.

Description of drawings

Fig. 1 is a perspective view of a crucible body in a preferred embodiment of the present invention.

Fig. 2 is a front view of a crucible body in a preferred embodiment of the present invention.

Fig. 3 is a schematic structural view of a thermal insulation bushing in a preferred embodiment of the present invention.

Fig. 4 is a schematic structural diagram of an inverted pouring melting system in a preferred embodiment of the present invention.

Fig. 5 is a schematic diagram of cooperation between the crucible body and the arc-shaped slide rail in a preferred embodiment of the present invention.

Fig. 6 is a schematic diagram of the coordinates of the crucible body when it is turned over in a preferred embodiment of the present invention.

Fig. 7 is a schematic structural diagram of an inverted pouring melting system according to a preferred embodiment of the present invention.

Fig. 8 is a schematic diagram of a tundish structure in a preferred embodiment of the present invention.

Explanation of reference signs:

Melting inner crucible 1

Insulated outer crucible 2

Fused magnesia 3

slider 4

ceramic base 401

ball head 402

Insulation bushing 5

Annular groove 501

Ball 502

Curved Rail 6

induction coil 7

swivel arm 8

Tundish 9

Tundish body 901

Refractory clay layer 902

Magnesium oxide coating 903

Detailed ways

The present invention is further illustrated below by means of examples, but the present invention is not therefore limited to the scope of the following examples.

As shown in Figures 1-3, this embodiment discloses a melting crucible, which includes a crucible body and a heat insulating liner 5. The inner wall of the heat insulating liner 5 is provided with an annular groove 501 along the circumference, and the annular groove 501 is provided with multiple A ball 502 is distributed along the circumferential direction of the annular groove 501. The crucible body is arranged in the heat-insulating liner 5. The outer wall of the crucible body is in contact with the balls 502 and the crucible body can rotate relative to the heat-insulation liner 5.

In this embodiment, the smelting crucible adopts the above-mentioned structure. When the molten metal is poured, the crucible body will automatically rotate with the pouring of the smelting crucible, so that the gate is always at the bottom to ensure the metal melt relative to the tundish 9. The position of the pouring port remains unchanged, so that the liquid injection of the molten metal is always on the same line as the central axis of the tundish 9 during the casting process, so as to avoid the molten metal splashing on the inner wall of the tundish 9 or the ceramic gate with a lower temperature. Position, resulting in loss of superheat, resulting in blockage of the atomization catheter, or reducing the fine powder rate of gas atomization powder.

In this embodiment, the heat insulating liner 5 is a cylindrical structure with both ends open, and the height of the heat insulating liner 5 may be smaller than that of the crucible body, or equal to or slightly greater than that of the crucible body.

As shown in Figures 1 and 2, the crucible body includes a melting inner crucible 1 and a heat-insulating outer crucible 2. The melting inner crucible 1 is arranged on the inner side of the heat-insulating outer crucible 2 and is relatively fixed. The outer surface of the heat-insulating outer crucible 2 is in contact with the ball 502 abutment. In this embodiment, the crucible body is provided with a heat-insulating outer crucible 2 to insulate the smelting inner crucible 1 to prevent the decrease in the temperature of the metal melt from affecting the fine powder rate of the gas atomization pulverization.

As shown in FIG. 2 , in this embodiment, fused magnesia 3 is filled between the melting inner crucible 1 and the heat-insulating outer crucible 2 . By filling the fused magnesia 3 between the smelting inner crucible 1 and the heat-insulating outer crucible 2, the two can be relatively fixed, and the relative movement of the two can be avoided.

In other embodiments, the melting inner crucible 1 and the heat-insulating outer crucible 2 can also be filled with other high-temperature-resistant materials, as long as the melting inner crucible 1 and the heat-insulating outer crucible 2 are relatively fixed and will not become loose due to high temperature. .

As shown in FIG. 3 , the inner wall of the heat insulating bush 5 is provided with a plurality of annular grooves 501 along the circumference, and the plurality of annular grooves 501 are evenly spaced along the height direction of the heat insulating bush 5 . The number of annular grooves 501 is reasonably arranged according to the size of the thermal insulation bushing 5 , which will not be described in detail here.

The annular groove 501 on the inner wall of the heat insulating liner 5 adopts the above-mentioned structure, which can make the rotation between the crucible body and the heat insulating liner 5 more stable, and no rotation deviation will affect the pouring of the molten metal.

In this embodiment, the thermal insulation bushing 5 is made of ceramic material. In other embodiments, the thermal insulation bushing 5 can also be made of other high temperature resistant thermal insulation materials. The selection of ceramic materials can be selected according to requirements, and will not be described in detail here.

In this embodiment, the ball 502 is a spherical pure zirconia ceramic ball. In other embodiments, the ball 502 can also be made of other high-temperature-resistant and wear-resistant materials.

In this embodiment, when the balls 502 are installed in the annular groove 501 , the balls 502 in the annular groove 501 are connected in pairs, that is, the annular groove 501 is filled with balls 502 . Of course, in other implementation manners, there may be gaps between the balls 502 , as long as the crucible body rotates smoothly relative to the heat insulating liner 5 .

As shown in FIGS. 4-6 , an embodiment of the present invention also provides an inversion pouring and melting system for vacuum atomization powder production, and the inversion pouring and melting system includes the above-mentioned melting crucible.

Wherein, the inverted pouring and smelting system further includes an induction coil 7 , and the induction coil 7 is arranged on the outer wall of the heat-insulation bushing 5 . The induction coil 7 and the thermal insulation bushing 5 are kept relatively fixed by the refractory mortar. The flip pouring smelting system heats and keeps warm the metal melt in the smelting crucible through the induction coil 7 .

The overturning pouring melting system also includes an arc-shaped slide rail 6 , a slide block 4 is provided at the bottom of the crucible body, and the slide block 4 is slidingly matched with the arc-shaped slide rail 6 . The arc-shaped slide rail 6 is arranged so that when the slider 4 slides from bottom to top along the arc-shaped slide rail 6, the sprue of the crucible body turns downward. By adopting the above structure, the inversion of the melting crucible can be better controlled, so that the gate of the melting crucible can be turned downward along a predetermined track, so that the metal melt can be poured into the tundish 9 smoothly. The curved slide rail 6 in this embodiment is made of stainless steel.

Specifically, in this embodiment, the slider 4 is fixed on the heat-insulating outer crucible 2 . The bottom of the heat-insulating outer crucible 2 is provided with a ceramic base 401. The ceramic base 401 is in the shape of a cone. The cone tip of the ceramic base 401 has a ball head 402. Rail 6. The ceramic base 401 and the ball head 402 form the slider 4 .

The inverted pouring melting system also includes a tundish 9, which is arranged on the side of the crucible body whose opening is turned downward. As shown in Figure 8, the tundish 9 includes a tundish body 901 made of graphite, and the inner wall of the tundish body 901 is coated with a refractory cement layer 902, and the refractory cement layer 902 includes 85% magnesia and 15% by weight. Aluminum borate. By setting the above-mentioned refractory clay layer 902, the tundish 9 is not easy to crack, and can effectively isolate the graphite from the metal melt, so as to prevent the metal melt from being polluted and affecting the fine powder rate of the metal gas atomization pulverization. Wherein, the thickness of the refractory cement layer 902 is preferably 8-10 mm, and of course it can also be adjusted according to the actual situation.

The inner wall surface of the refractory cement layer 902 of the tundish 9 is coated with a layer of magnesium oxide coating 903, and the magnesium oxide coating 903 is mixed with liquid sodium silicate and evenly coated on the inner wall of the refractory cement layer 902 to reduce other elements. Contaminate the metal melt, keep the chemical composition pure, and ensure the fine powder rate of metal gas atomization powder making.

The tundish 9 of the flip casting smelting system is induced by an intermediate frequency induction power supply, and is directly transferred to the refractory cement through heat conduction, which can make the middle and upper part of the inner wall of the tundish 9 reach a temperature above 1600°C, which is 100°C higher than the heat preservation temperature of the existing tundish 9 ℃-200℃, which is further beneficial to maintain a high degree of superheat in the process of metal melt, and improve the fine powder rate of metal gas atomization powder making.

The overturning pouring melting system also includes a rotating arm 8 connected to the heat insulation bushing 5 , and the rotating arm 8 is used to drive the melting crucible to rotate along the preset track of the arc-shaped slide rail 6 . In this embodiment, the rotating arm 8 is fixedly connected to the two ends of the induction coil 7 .

When the flipping pouring smelting system is in operation, the combination of the melting inner crucible 1 and the heat-insulating outer crucible 2 (ie, the crucible body) in the heat-insulating lining 5 is driven by the rotation of the rotating arm 8, not only making the crucible body relative to the heat-insulating lining The sleeve 5 rotates so that the gate of the crucible body is always at the bottom, and also makes the ball head 402 on the ceramic base 401 at the bottom of the combination of the melting inner crucible 1 and the heat-insulating outer crucible 2 slide along the arc-shaped slide rail 6, During the sliding process, the combination of the melting inner crucible 1 and the heat insulating outer crucible 2 will move axially along the heat insulating liner 5, so that the gate of the melting inner crucible 1 (that is, the metal melt pouring port) is always in the tundish. 9, so that the metal melt will not be cast on the wall of the tundish 9 during the pouring process and reduce its superheat.

As shown in Figures 5 to 7, the ball head 402 of the slider 4 at the bottom of the melting crucible is installed in the arc-shaped slide rail 6, and the slideway structure of the arc-shaped slide rail 6 can be designed through calculation, so that the melting inner crucible 1 The lowest point D of the gate is always on the central axis of the tundish 9 . Specifically as shown in Figure 5:

Known: ① The diameter of the inner crucible 1 in the smelting d=CD;

2. the coordinates (x _A , y _A ) of the rotational axis A of the induction coil 7;

③ The angle α between the axis of the melting inner crucible 1 and the horizontal line;

4. The total length I=BC of the melting inner crucible 1, the heat-insulating outer crucible 2, the ceramic base 401 and the ball head 402;

The coordinates (x _B , y _B ) of the contact point B between the ball head 402 and the curved slide rail 6 can be obtained, and the specific calculation process is as follows:

l _AC ＝x _A /cosα-d tanα

n _AB = n _BC -l _AC

x _B ＝x _A +l _AB cosα＝n _BC cosα+dsinα

y _B ＝y _A -l _AB sinα＝y _A -n _BC sinα+x _A tanα-d tanα sinα

The slide track structure of the arc slide rail 6 can be obtained by the coordinates of the contact point B between the ball head 402 and the arc slide rail 6 .

Although the specific implementation of the present invention has been described above, those skilled in the art should understand that this is only an example, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principle and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims (10)

1. The utility model provides a smelting crucible, its characterized in that includes crucible body and thermal-insulated bush, be equipped with the ring channel along circumference on the inner wall of thermal-insulated bush, be equipped with a plurality of edges in the ring channel the ball of ring channel circumference distribution, the crucible body is located in the thermal-insulated bush, the outer wall of crucible body with ball butt just the crucible body can rotate relative the thermal-insulated bush.

2. The melting crucible of claim 1, wherein the crucible body comprises an inner melting crucible and an outer insulating crucible, the inner melting crucible being disposed inside the outer insulating crucible and being relatively fixed, the outer surface of the outer insulating crucible being in abutment with the balls.

3. The melting crucible of claim 2 wherein fused magnesia is filled between the inner and outer melting crucibles.

4. The melting crucible of claim 1, wherein there are a plurality of annular grooves;

and/or the annular groove is in a circular shape;

and/or, the heat insulation lining is made of ceramic material;

and/or the ball is spherical pure zirconia ceramic beads;

and/or the balls in the annular grooves are connected in pairs.

5. A turnover casting smelting system for vacuum gas atomization pulverizing, characterized in that the turnover casting smelting system comprises a smelting crucible according to any one of claims 1 to 4.

6. The roll-over pour smelting system for vacuum atomization milling of claim 5 further comprising an induction coil disposed on an outer sidewall of the insulating sleeve.

7. The turnover casting smelting system for vacuum atomization pulverizing of claim 5, further comprising an arc-shaped slide rail, wherein a slide block is arranged at the bottom of the crucible body and is in sliding fit with the arc-shaped slide rail; the arc-shaped sliding rail is arranged so that when the sliding block slides from bottom to top along the arc-shaped sliding rail, the pouring gate of the crucible body turns downwards.

8. The turnover casting melting system for vacuum atomization pulverizing of claim 7, further comprising a rotating arm connected to the heat insulation bushing for driving the melting crucible to rotate along a preset track of the arc-shaped slide rail.

9. The turnover casting smelting system for vacuum atomization pulverizing of claim 5, further comprising a tundish provided at one side of the opening of the crucible body turned downward;

the tundish comprises a tundish body made of graphite, wherein the inner wall of the tundish body is coated with a refractory mortar layer, and the refractory mortar layer comprises 85% of magnesium oxide and 15% of aluminum borate in parts by weight.

10. The turnover casting smelting system for vacuum atomization pulverizing of claim 9, wherein the thickness of the refractory mortar layer is 8-10mm;

and/or the inner wall surface of the refractory mortar layer is coated with a magnesium oxide coating, and the magnesium oxide coating is mixed by liquid sodium silicate and uniformly coated on the inner wall of the refractory mortar layer.

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