Melting crucible and tumble pouring melting system for vacuum gas atomization powder making

Abstract

The present invention discloses a smelting crucible and a tumble pouring smelting system for vacuum gas atomization powder making, wherein the smelting crucible comprises a crucible body and a heat-insulating bushing, wherein an annular groove is provided on the inner wall of the heat-insulating bushing in the circumferential direction, wherein a plurality of balls distributed along the circumferential direction of the annular groove are provided in the annular groove, wherein the crucible body is arranged in the heat-insulating bushing, wherein the outer wall of the crucible body abuts against the balls and the crucible body can rotate relative to the heat-insulating bushing. When the smelting crucible of the present invention is used for pouring molten metal, the crucible body will automatically rotate with the tipping of the smelting crucible, so that the pouring port is always at the bottom, so that the pouring port of the molten metal relative to the tundish is kept unchanged, and then the liquid injection of the molten metal is always in the same straight line with the central axis of the tundish during the casting process, so as to avoid the molten metal splashing on the inner wall of the tundish or the ceramic pouring port and other places with lower temperature, resulting in superheat loss, resulting in blockage of the atomization liquid guide tube, or reducing the fine powder rate of gas atomization powder making.

Description

Technical Field

[0001] The invention relates to the technical field of vacuum gas atomization powder making, and in particular to a smelting crucible and a tumbling pouring smelting system for vacuum gas atomization powder making. Background Art

[0002] 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 gas electrode induction atomization (VIGA). VIGA uses high-pressure argon gas to crush and solidify the metal melt in the crucible into metal powder.

[0003] In the gas atomization process, in addition to the gas atomization nozzle, the alloy smelting system plays a key role. The smelting system of industrial-grade gas atomization powder making is usually achieved by flip casting. The molten metal in the melting crucible is poured into the tundish by flip casting. Since the position of the molten metal relative to the pouring port of the tundish changes during the flipping of the melting crucible, part of the melt will fall into the middle and upper parts of the tundish with lower temperature, causing superheat loss, thereby affecting the powder yield. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defects in the prior art and provide a smelting crucible and a tumble pouring smelting system for vacuum gas atomization powder making.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] The present invention provides a smelting crucible, comprising a crucible body and a thermal insulation sleeve, wherein an annular groove is circumferentially arranged on the inner wall of the thermal insulation sleeve, a plurality of balls are circumferentially distributed in the annular groove, the crucible body is arranged in the thermal insulation sleeve, the outer wall of the crucible body abuts against the balls and the crucible body can rotate relative to the thermal insulation sleeve.

[0007] In the present scheme, the melting crucible adopts the above-mentioned structure. When pouring the molten metal, the crucible body will automatically rotate as the melting crucible is tilted, so that the pouring gate is always at the bottom, ensuring that the position of the molten metal relative to the pouring gate of the tundish remains unchanged, thereby ensuring that the liquid injection of the molten metal is always in the same line with the central axis of the tundish during the casting process, thereby preventing the molten metal from splashing on the inner wall of the tundish or the ceramic pouring gate and other lower temperature locations, causing superheat loss, resulting in blockage of the atomization liquid guide tube, or reducing the fine powder rate of gas atomization powder making.

[0008] Preferably, the crucible body comprises a smelting inner crucible and an insulating outer crucible, the smelting inner crucible is arranged inside the insulating outer crucible and is relatively fixed, and the outer surface of the insulating outer crucible abuts against the ball.

[0009] In this solution, the crucible body is provided with an insulating outer crucible to insulate the inner crucible for smelting, so as to prevent the temperature of the molten metal from decreasing and affecting the fine powder rate of gas atomization powder making.

[0010] Preferably, the space between the inner smelting crucible and the outer insulating crucible is filled with fused magnesia sand.

[0011] In this solution, by filling fused magnesia sand between the inner smelting crucible and the outer insulating crucible, the two can be relatively fixed to avoid relative movement between the two.

[0012] Preferably, there are multiple annular grooves;

[0013] And / or, the annular groove is in a circular ring shape.

[0014] In this solution, the above structure is adopted to make the rotation between the crucible body and the heat-insulating bushing more stable, and no rotation deviation will occur to affect the pouring of the molten metal.

[0015] Preferably, the thermal insulation bushing is made of ceramic material;

[0016] And / or, the balls are spherical pure zirconia ceramic beads.

[0017] Preferably, the balls in the annular groove are connected to each other in pairs.

[0018] The present invention also provides a tumble pouring smelting system for vacuum gas atomization powder making, wherein the tumble pouring smelting system comprises the smelting crucible as described above.

[0019] Preferably, the tumble pouring and smelting system further comprises an induction coil, and the induction coil is arranged on the outer side wall of the thermal insulation bushing.

[0020] Preferably, the induction coil and the thermal insulation bushing are kept relatively fixed by refractory cement.

[0021] Preferably, the flip pouring smelting system also includes an arc-shaped slide rail, and a slider is provided at the bottom of the crucible body, and the slider slidably cooperates with the arc-shaped slide rail; the arc-shaped slide rail is configured so that when the slider slides from bottom to top along the arc-shaped slide rail, the pouring mouth of the crucible body flips downward.

[0022] In this solution, the above structure is adopted to better control the turning of the melting crucible, so that the pouring mouth of the melting crucible turns downward along a predetermined trajectory, so that the molten metal can be smoothly poured into the tundish.

[0023] Preferably, the tumble pouring smelting system further comprises a rotating arm, wherein the rotating arm is connected to the heat insulating bushing, and the rotating arm is used to drive the smelting crucible to rotate along a preset track of the arc-shaped slide rail.

[0024] Preferably, the tumble pouring smelting system further comprises a tundish, which is arranged on the side of the crucible body with its opening turned downward;

[0025] The tundish comprises a tundish body made of graphite, the inner wall of the tundish body is coated with a refractory clay layer, and the refractory clay layer comprises 85% by weight of magnesium oxide and 15% by weight of aluminum borate.

[0026] Preferably, the thickness of the refractory clay layer is 8-10 mm.

[0027] Preferably, the inner wall surface of the refractory clay layer is coated with a magnesium oxide coating, and the magnesium oxide coating is mixed with liquid sodium silicate and uniformly coated on the inner wall of the refractory clay layer.

[0028] The positive and progressive effect of the present invention is that when the melting crucible of the present invention is used for pouring molten metal, the crucible body will automatically rotate as the melting crucible is tilted, so that the pouring mouth is always at the bottom, ensuring that the position of the molten metal relative to the pouring mouth of the tundish remains unchanged, thereby ensuring that the liquid injection of the molten metal is always in the same straight line with the central axis of the tundish during the casting process, thereby preventing the molten metal from splashing on the inner wall of the tundish or the ceramic pouring mouth and other locations with lower temperatures, causing superheat loss, resulting in blockage of the atomization liquid guide tube, or reducing the fine powder rate of gas atomization powder making. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 FIG. 4 is a three-dimensional diagram of a crucible body according to a preferred embodiment of the present invention.

[0030] Figure 2 It is a front view of the crucible body of a preferred embodiment of the present invention.

[0031] Figure 3 It is a schematic structural diagram of a heat-insulating bushing according to a preferred embodiment of the present invention.

[0032] Figure 4 It is a schematic structural diagram of a tumble pouring and smelting system according to a preferred embodiment of the present invention.

[0033] Figure 5 Schematic diagram of the cooperation between the crucible body and the arc-shaped slide rail in a preferred embodiment of the present invention.

[0034] Figure 6 Schematic diagram of coordinates of the crucible body when it is turned over in a preferred embodiment of the present invention.

[0035] Figure 7It is a schematic structural diagram of a tumble pouring and smelting system according to a preferred embodiment of the present invention.

[0036] Figure 8 This is a schematic diagram of the structure of the tundish according to a preferred embodiment of the present invention.

[0037] Description of reference numerals:

[0038] Melting inner crucible 1

[0039] Insulated outer crucible 2

[0040] Fused magnesia 3

[0041] Slider 4

[0042] Ceramic base 401

[0043] Ball head 402

[0044] Thermal insulation bushing 5

[0045] Annular groove 501

[0046] Ball 502

[0047] Curved slide rail 6

[0048] Induction coil 7

[0049] Rotating arm 8

[0050] Tundish 9

[0051] Tundish body 901

[0052] Refractory clay layer 902

[0053] Magnesium oxide coating 903 DETAILED DESCRIPTION

[0054] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the following examples.

[0055] like Figure 1-3 As shown, this embodiment discloses a smelting crucible, including a crucible body and an insulating sleeve 5, an inner wall of the insulating sleeve 5 is provided with an annular groove 501 along the circumferential direction, a plurality of balls 502 distributed along the circumferential direction of the annular groove 501 are provided in the annular groove 501, the crucible body is arranged in the insulating sleeve 5, the outer wall of the crucible body is in contact with the balls 502, and the crucible body can rotate relative to the insulating sleeve 5.

[0056] In this embodiment, the melting crucible adopts the above-mentioned structure. When pouring the molten metal, the crucible body will automatically rotate with the tilting of the melting crucible, so that the pouring gate is always at the bottom, ensuring that the position of the molten metal relative to the pouring port of the tundish 9 remains unchanged, thereby ensuring that the liquid injection of the molten metal is always in the same line with the central axis of the tundish 9 during the casting process, thereby preventing the molten metal from splashing on the inner wall of the tundish 9 or the ceramic pouring gate and other locations with lower temperatures, causing superheat loss, resulting in blockage of the atomization liquid guide tube, or reducing the fine powder rate of gas atomization powder making.

[0057] In this embodiment, the heat insulating bushing 5 is a cylindrical structure with openings at both ends. The height of the heat insulating bushing 5 can be less than the height of the crucible body, or can be equal to or slightly greater than the height of the crucible body.

[0058] like Figure 1 and Figure 2 As shown, the crucible body includes a smelting inner crucible 1 and an insulating outer crucible 2. The smelting inner crucible 1 is arranged on the inner side of the insulating outer crucible 2 and is relatively fixed. The outer surface of the insulating outer crucible 2 abuts against the ball 502. In this embodiment, the crucible body is provided with an insulating outer crucible 2 to insulate the smelting inner crucible 1 to prevent the temperature of the molten metal from decreasing and affecting the fine powder rate of gas atomization powder making.

[0059] like Figure 2 As shown, in this embodiment, fused magnesia sand 3 is filled between the inner smelting crucible 1 and the insulating outer crucible 2. By filling the fused magnesia sand 3 between the inner smelting crucible 1 and the insulating outer crucible 2, the two can be relatively fixed to avoid relative movement between the two.

[0060] In other embodiments, the inner melting crucible 1 and the insulating outer crucible 2 may also be filled with other high temperature resistant materials, as long as the inner melting crucible 1 and the insulating outer crucible 2 are relatively fixed and will not loosen due to high temperature.

[0061] like Figure 3 As shown, a plurality of annular grooves 501 of annular structure are arranged circumferentially on the inner wall of the heat insulating bushing 5, and the plurality of annular grooves 501 are evenly spaced along the height direction of the heat insulating bushing 5. The number of annular grooves 501 is reasonably arranged according to the size of the heat insulating bushing 5, and will not be described in detail here.

[0062] The annular groove 501 on the inner wall of the heat-insulating bushing 5 adopts the above structure, which can make the rotation between the crucible body and the heat-insulating bushing 5 more stable, and will not cause rotation deviation to affect the pouring of the molten metal.

[0063] In this embodiment, the heat insulating bushing 5 is made of ceramic material. In other embodiments, the heat insulating bushing 5 can also be made of other high temperature resistant heat insulating materials. The selection of ceramic material can be selected according to demand, and will not be described in detail here.

[0064] In this embodiment, the ball 502 is a spherical pure zirconium oxide ceramic ball. In other embodiments, the ball 502 can also be made of other high temperature resistant and wear-resistant materials.

[0065] In this embodiment, when the balls 502 are installed in the annular groove 501, the balls 502 in the annular groove 501 are connected to each other, that is, the annular groove 501 is full of balls 502. Of course, in other embodiments, gaps can be left between the balls 502 as long as the stable rotation of the crucible body relative to the insulation bushing 5 is not affected.

[0066] like Figure 4-6 As shown, an embodiment of the present invention further provides a tumble pouring smelting system for vacuum gas atomization powder making, and the tumble pouring smelting system includes the above-mentioned smelting crucible.

[0067] The tumble pouring smelting system further comprises an induction coil 7, which is arranged on the outer wall of the heat insulating bushing 5. The induction coil 7 and the heat insulating bushing 5 are relatively fixed by refractory cement. The tumble pouring smelting system heats and keeps the molten metal in the smelting crucible warm by the induction coil 7.

[0068] The overturned pouring smelting system also includes an arc-shaped slide rail 6. A slider 4 is provided at the bottom of the crucible body, and the slider 4 slides with the arc-shaped slide rail 6. The arc-shaped slide rail 6 is configured so that when the slider 4 slides from bottom to top along the arc-shaped slide rail 6, the pouring mouth of the crucible body turns downward. By adopting the above structure, the turning of the smelting crucible can be better controlled, so that the pouring mouth of the smelting crucible turns downward along a predetermined trajectory, so that the molten metal can be smoothly poured into the tundish 9. The arc-shaped slide rail 6 in this embodiment is made of stainless steel.

[0069] Specifically, in this embodiment, the slider 4 is fixed on the insulating outer crucible 2. A ceramic base 401 is provided at the bottom of the insulating outer crucible 2. The ceramic base 401 is conical, and the conical tip of the ceramic base 401 has a ball head 402. The ball head 402 has a diameter of about 60 mm-100 mm, and the ball head 402 is inserted into the arc-shaped slide rail 6. The ceramic base 401 and the ball head 402 constitute the slider 4.

[0070] The tumble pouring smelting system further includes a tundish 9, which is arranged on the side of the crucible body with its opening turned downward. Figure 8As shown, 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 clay layer 902, and the refractory clay layer 902 includes 85% by weight of magnesium oxide and 15% by weight of aluminum borate. By providing the above-mentioned refractory clay layer 902, the tundish 9 is not easy to crack, and the graphite can be effectively isolated from the contact with the metal melt, so as to avoid the metal melt being contaminated and affecting the fine powder rate of the metal gas atomization powder. Among them, the thickness of the refractory clay layer 902 is preferably 8-10mm, and of course it can also be adjusted according to actual conditions.

[0071] The inner wall surface of the refractory clay layer 902 of the tundish 9 is coated with a layer of magnesium oxide coating 903. The magnesium oxide coating 903 is mixed with liquid sodium silicate and evenly coated on the inner wall of the refractory clay layer 902 to reduce the contamination of the metal melt by other elements, maintain the purity of the chemical composition, and ensure the fine powder rate of metal gas atomization powder making.

[0072] The tundish 9 of the tumble pouring smelting system is induced by a medium-frequency induction power supply and directly transferred to the refractory clay by 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-200°C higher than the insulation temperature of the existing tundish 9, further helping to maintain a high superheat in the metal melt process and improve the fine powder rate of metal gas atomization powder making.

[0073] The tumble pouring smelting system further comprises a rotating arm 8, which is connected to the heat insulating bushing 5 and is used to drive the smelting crucible to rotate along a preset track of the arc-shaped slide rail 6. In this embodiment, the rotating arm 8 is fixedly connected to two ends of the induction coil 7.

[0074] When the flip pouring smelting system is working, the rotating arm 8 drives the combination of the inner smelting crucible 1 and the outer smelting crucible 2 (i.e., the crucible body) in the insulating sleeve 5 to rotate, which not only makes the crucible body rotate relative to the insulating sleeve 5 so that the pouring mouth of the crucible body is always located at the bottom, but also makes the ball head 402 on the ceramic base 401 at the bottom of the combination of the inner smelting crucible 1 and the outer smelting crucible 2 slide along the arc-shaped slide rail 6. During the sliding process, the combination of the inner smelting crucible 1 and the outer smelting crucible 2 will simultaneously rotate along the central axis of the insulating sleeve 5, so that the pouring mouth of the inner smelting crucible 1 (i.e., the pouring port of the molten metal) is always on the central axis of the tundish 9, so that the molten metal will not be cast on the wall of the tundish 9 during the pouring process, thereby reducing its superheat.

[0075] like Figures 5 to 7 As shown, the ball head 402 of the slider 4 at the bottom of the melting crucible is installed in the arc-shaped slide rail 6. The slideway structure of the arc-shaped slide rail 6 can be designed by calculation so that the lowest point D of the pouring port of the melting inner crucible 1 is always on the central axis of the tundish 9. Figure 5 As shown:

[0076] Known: ① The diameter of the inner crucible 1 is d = CD;

[0077] ② The coordinates of the rotation axis A of the induction coil 7 (x A ,y A );

[0078] ③ Angle α between the axis of the inner crucible 1 and the horizontal line;

[0079] ④ The total length l of the melting inner crucible 1, the insulating outer crucible 2, the ceramic base 401 and the ball head 402 is BC;

[0080] The coordinates (x B ,y B ), the specific calculation process is as follows:

[0081] l AC =x A / cosα-d tanα

[0082] l AB = l BC -l AC

[0083] x B =x A +l AB cosα=l BC cosα+dsinα

[0084] y B =y A -l AB sinα=y A -l BC sinα+x A tanα-dtanαsinα

[0085] The slideway structure of the arc-shaped slideway 6 can be obtained through the coordinates of the contact point B between the ball head 402 and the arc-shaped slideway 6 .

[0086] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A tumble pouring smelting system for vacuum gas atomization powder making, characterized in that: The tumble pouring smelting system includes a smelting crucible, the smelting crucible includes a crucible body and a heat-insulating bushing, an annular groove is circumferentially provided on the inner wall of the heat-insulating bushing, a plurality of balls are circumferentially distributed in the annular groove, the crucible body is arranged in the heat-insulating bushing, the outer wall of the crucible body abuts against the balls, and the crucible body can rotate relative to the heat-insulating bushing; The overturning pouring and melting system further comprises an arc-shaped slide rail, a slider is provided at the bottom of the crucible body, and the slider is slidably matched with the arc-shaped slide rail; the arc-shaped slide rail is configured so that when the slider slides from bottom to top along the arc-shaped slide rail, the pouring port of the crucible body turns downward; The tumble pouring smelting system further comprises a rotating arm, the rotating arm being connected to the heat insulating bushing, and the rotating arm being used to drive the smelting crucible to rotate along a preset track of the arc-shaped slide rail; The tumble pouring smelting system also includes a tundish, which is arranged on the side of the crucible body with its opening turned downward, and a pouring gate is provided on the crucible body. The crucible body is configured to rotate relative to the insulating bushing when the smelting crucible slides along the arc-shaped slide rail, so that the pouring gate is always located at the bottom and remains on the central axis of the tundish.

2. The tumble pouring smelting system for vacuum gas atomization powder making according to claim 1, characterized in that: The tumble pouring and smelting system further comprises an induction coil, and the induction coil is arranged on the outer side wall of the thermal insulation bushing.

3. The tumble pouring smelting system for vacuum gas atomization powder making according to claim 1, characterized in that: The tundish comprises a tundish body made of graphite, the inner wall of the tundish body is coated with a refractory clay layer, and the refractory clay layer comprises 85% by weight of magnesium oxide and 15% by weight of aluminum borate.

4. The tumble pouring smelting system for vacuum gas atomization powder making according to claim 3, characterized in that: The thickness of the refractory clay layer is 8-10 mm; And / or, the inner wall surface of the refractory clay layer is coated with a magnesium oxide coating, and the magnesium oxide coating is mixed with liquid sodium silicate and uniformly coated on the inner wall of the refractory clay layer.

5. The tumble pouring smelting system for vacuum gas atomization powder making according to claim 1, characterized in that: The crucible body comprises a smelting inner crucible and an insulating outer crucible. The smelting inner crucible is arranged inside the insulating outer crucible and is relatively fixed. The outer surface of the insulating outer crucible abuts against the ball.

6. The tumble pouring smelting system for vacuum gas atomization powder making according to claim 5, characterized in that: The space between the inner smelting crucible and the outer insulating crucible is filled with fused magnesia sand.

7. The tumble pouring smelting system for vacuum gas atomization powder making according to claim 1, characterized in that: There are multiple annular grooves; And / or, the annular groove is in the shape of a circular ring; And / or, the thermal insulation bushing is made of ceramic material; And / or, the balls are spherical pure zirconia ceramic balls; And / or, the balls in the annular groove are connected to each other in pairs.

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