Anti-gravity investment precision casting molten metal self-sealing device and method

Abstract

The invention provides an anti-gravity molten metal self-sealing device and method for investment casting, and belongs to the technical field of investment casting, the device comprises a sand box, a ceramic shell, a sealing ring, a middle partition plate and a ceramic riser tube, the sand box is provided with a first groove, and the side face of the first groove is provided with a first inclined guide face; the ceramic shell is provided with an outer conical surface; a conical through hole is formed in the sealing ring, a first surface of the sealing ring is a plane, a second inclined guide surface is arranged on the combined outer edge of the first surface, a second surface of the sealing ring is an annular boss, and a cooling medium is introduced into the sealing ring; a second groove is formed in the middle partition plate, and a mounting through hole is formed in the middle partition plate; the ceramic riser tube is of a cylindrical structure, and the head is provided with a mounting boss. The method comprises the steps that the ceramic shell is buckled in the sand box; a sealing ring and a middle partition plate are assembled; the ceramic shell falls on the ceramic riser tube; a cooling medium is introduced into the sealing ring; and the riser tube is inserted into the crucible. The assembly precision of the ceramic shell and the riser tube is effectively guaranteed in the investment precision casting process, and the self-sealing performance of molten metal is improved.

Description

Technical Field

[0001] This invention relates to the field of anti-gravity casting technology, and in particular to an apparatus and method that can effectively improve the assembly accuracy of ceramic mold shells and riser pipes, as well as the sealing performance of molten metal during investment casting. Background Technology

[0002] Currently, anti-gravity investment casting is an advanced casting technology where molten metal fills and solidifies from bottom to top along a riser pipe under gas pressure. Leveraging its advantages of stable and controllable molten metal filling and pressure-enhanced feeding, it has been widely used in casting complex thin-walled parts of lightweight alloys such as aluminum and magnesium alloys, and is gradually expanding into the field of high-temperature alloys. High-temperature alloys, widely used in hot-end components of high-end equipment, have high density and melting points, requiring even higher metal filling temperatures and holding pressures for anti-gravity investment casting. The assembly point between the ceramic mold and the riser pipe, as the front end of the high-temperature, high-pressure molten metal filling process, is highly susceptible to molten metal leakage. The sealing technologies used in traditional lightweight alloy anti-gravity casting are no longer sufficient to meet the process requirements. Furthermore, to achieve lightweighting goals, high-temperature alloy castings in high-end equipment in the aerospace, aviation, and marine industries tend towards thinner walls and integral designs, with large-area thin-walled structures exceeding 1mm in wall thickness. To ensure complete filling of the casting, further increases in molten metal filling temperatures and holding pressures are needed, posing further challenges to high-temperature, high-pressure molten metal sealing technology. Patent CN114888239A proposes a two-stage wedge-shaped sealing structure for anti-gravity casting of high-temperature alloys, which ensures a good seal between the riser tube and the ceramic mold shell. However, the two-stage wedge-shaped structure relies heavily on the precise assembly of the riser tube and the ceramic mold shell, as well as the temperature resistance of the wedge-shaped sealing gasket, and there is still a certain risk of molten metal leakage.

[0003] Therefore, how to effectively ensure the assembly accuracy of the ceramic mold shell and the riser tube and improve the self-sealing performance of the molten metal during the investment casting process is an urgent problem to be solved in the industry. Summary of the Invention

[0004] A primary objective of this invention is to overcome at least one of the deficiencies of the prior art and to provide an anti-gravity investment casting molten metal self-sealing device and method that can effectively ensure the assembly accuracy of the ceramic mold shell and the riser pipe and improve the self-sealing performance of the molten metal during the investment casting process.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: According to one aspect of the present invention, a self-sealing device for anti-gravity investment casting molten metal is provided, comprising: A sand box containing sand, with a first groove at the opening and a first inclined guide surface on the side of the first groove; A ceramic shell is fastened inside the sand box and wrapped inside the sand. The opening of the ceramic shell corresponds to the opening of the sand box, and the outer edge of the opening of the ceramic shell is provided with an outer conical surface. A sealing ring, wherein the sealing ring has a tapered through hole inside, the first surface of the sealing ring is a plane, the first surface is combined with the outer edge having a second inclined guide surface, the second surface of the sealing ring is a circular boss, the first surface and the second surface are opposite to each other, a cooling medium flows through the sealing ring, the first surface matches the first groove, the second inclined guide surface matches the first inclined guide surface, and the tapered through hole matches the outer tapered surface; A partition plate is provided with a second groove, which is elastically connected to the annular boss. The bearing surface of the partition plate abuts against the sealing ring and the bottom of the sand box. The partition plate has a mounting through hole. The ceramic riser tube is a cylindrical structure with a mounting boss at its head. The mounting boss is sandwiched between the middle partition and the ceramic shell, and its outer edge abuts against the tapered through hole. The central hole of the ceramic riser tube is connected to the opening of the ceramic shell.

[0006] According to a specific embodiment of the present invention, a spring is sandwiched between the second groove and the annular boss.

[0007] According to one specific embodiment of the present invention, there are 3-8 springs, which are evenly distributed in a circular symmetrical manner.

[0008] According to a specific embodiment of the present invention, the side fitting gap between the second groove and the annular boss is 1-5mm.

[0009] According to one specific embodiment of the present invention, the sealing ring has a hollow structure inside, and the hollow structure has an inlet and an outlet.

[0010] According to a specific embodiment of the present invention, the clearance between the sealing ring and the top surface of the circular boss is 2-8 mm.

[0011] According to a specific embodiment of the present invention, the fitting clearance between the outer diameter of the ceramic riser tube and the mounting through hole is greater than the side fitting clearance between the second groove and the annular boss.

[0012] According to a specific embodiment of the present invention, the ceramic shell is provided with a first convex-concave structure, and the ceramic riser tube is provided with a second convex-concave structure, wherein the first convex-concave structure and the second convex-concave structure are engaged in a snap-fit ​​connection.

[0013] According to a specific embodiment of the present invention, the first convex-concave structure includes a first convex ring and a first annular groove, and the second convex-concave structure includes a second convex ring and a second annular groove, wherein the first convex ring engages with the second annular groove, and the first annular groove engages with the second convex ring.

[0014] According to another aspect of the present invention, a self-sealing method for anti-gravity investment casting molten metal is provided, using the above-described anti-gravity investment casting molten metal self-sealing device, comprising the following steps: S1. The ceramic shell is placed in the sand box; S2. The sealing ring and the partition plate are assembled, and the ceramic riser tube is placed on the sealing ring and in the center hole of the partition plate. S3. The ceramic shell is placed on the ceramic riser tube and the assembly is completed; S4. Cooling medium is introduced into the sealing ring; S5. The ceramic riser tube is inserted into the crucible, and the pressure drives the molten metal to rise along the ceramic riser tube to complete the filling and solidification of the casting.

[0015] As can be seen from the above technical solution, the advantages and positive effects of the anti-gravity investment casting molten metal self-sealing device and method of the present invention are as follows: This invention ensures the assembly accuracy between the ceramic riser pipe and the ceramic shell through wedge-shaped guidance, and improves the self-sealing effect of molten metal leakage by adopting a cooling and sealing structure, which greatly improves the safety and reliability of the equipment process. Attached Figure Description

[0016] Figure 1 A schematic diagram of the overall structure of an embodiment of the anti-gravity investment casting molten metal self-sealing device of the present invention.

[0017] Figure 2 for Figure 1 Enlarged view of section A.

[0018] Figure 3 A schematic diagram of the structure of the ceramic mold shell and sand box in an embodiment of the self-sealing device for anti-gravity investment casting of molten metal according to the present invention.

[0019] Figure 4 A schematic diagram of the sealing ring structure of an embodiment of the anti-gravity investment casting molten metal self-sealing device of the present invention.

[0020] Figure 5 A schematic diagram of the partition structure in one embodiment of the anti-gravity investment casting molten metal self-sealing device of the present invention.

[0021] Figure 6 A schematic diagram of the ceramic riser structure of an embodiment of the anti-gravity investment casting molten metal self-sealing device of the present invention.

[0022] Figure 7A schematic diagram of the assembly structure of the ceramic shell and the riser pipe in an embodiment of the anti-gravity investment casting molten metal self-sealing device of the present invention.

[0023] Figure 8 A schematic diagram of the assembly structure of the sealing ring, partition plate and spring in an embodiment of the anti-gravity investment casting molten metal self-sealing device of the present invention.

[0024] Drawing number explanation: 1. Sand box; 11. First inclined guide surface; 2. Ceramic shell; 21. Outer conical surface; 22. First convex-concave structure; 3. Sealing ring; 31. Inlet; 32. Outlet; 33. Second inclined guide surface; 34. Conical through hole; 35. Circular boss; 36. First surface; 37. First positioning groove; 4. Middle partition plate; 41. Groove; 42. Mounting through hole; 43. Second positioning groove; 5. Ceramic riser pipe; 51. Outer edge; 52. Mounting boss; 53. Second convex-concave structure; 6. Spring. Detailed Implementation

[0025] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that the invention will be thorough and complete, and the concept of the exemplary embodiments will be fully conveyed to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed description will be omitted.

[0026] like Figures 1 to 8 As shown, according to one aspect of the present invention, an anti-gravity investment casting molten metal self-sealing device is provided, comprising a sand box 1, a ceramic mold shell 2, a sealing ring 3, a partition plate 4, and a ceramic riser pipe 5.

[0027] In this embodiment, the sand box 1 contains sand, and the opening of the sand box 1 has a first groove, and the side of the first groove has a first inclined guide surface 11.

[0028] In this embodiment, the ceramic shell 2 is fastened inside the sand box 1 and wrapped inside the sand. The opening of the ceramic shell 2 corresponds to the opening of the sand box 1, and an outer conical surface 21 is provided on the outer edge of the opening of the ceramic shell 2.

[0029] In this embodiment, the sealing ring 3 has a tapered through hole 34 inside. The first surface 36 of the sealing ring is flat, and the first surface 36 has a second inclined guide surface 33 combined with its outer edge. The second surface of the sealing ring is a circular boss 35. The first surface 36 and the second surface are opposite each other. A cooling medium flows through the sealing ring. The first surface 36 mates with the first groove, and the second inclined guide surface 33 mates with the first inclined guide surface 11. The tapered through hole 34 mates with the outer tapered surface 21. The sealing ring 3 is made of copper alloy.

[0030] In this embodiment, a second groove 41 is provided on the partition plate 4, the second groove 41 is elastically connected to the annular boss 35, the bearing surface of the partition plate 4 abuts against the bottom of the sealing ring 3 and the sand box 1, and the partition plate 4 has an installation through hole 42.

[0031] In this embodiment, the ceramic riser tube 5 is a cylindrical structure with a mounting boss 52 at the head. The mounting boss 52 is sandwiched between the middle partition plate 4 and the ceramic shell 2, and the outer edge 51 abuts against the tapered through hole 34. The central hole of the ceramic riser tube 5 is connected to the opening of the ceramic shell 2.

[0032] In this embodiment, a spring 6 is sandwiched between the second groove 41 and the annular boss 35, and the spring 6 is disposed between the first positioning groove 37 and the second positioning groove 43.

[0033] In this embodiment, there are 3-8 springs 6, which are evenly distributed in a symmetrical arrangement around the center, for example, 4 springs.

[0034] In this embodiment, the side fitting gap between the second groove 41 and the annular boss 35 is 1-5mm, for example 3mm or 4mm.

[0035] In this embodiment, the sealing ring 3 has a hollow structure inside, and the hollow structure has an inlet 31 and an outlet 32.

[0036] In this embodiment, the clearance between the sealing ring 3 and the top surface of the annular boss 35 is 2-8mm, for example, 5mm or 6mm.

[0037] In this embodiment, the fitting clearance between the outer diameter of the ceramic riser tube 5 and the mounting through hole 42 is 2-8mm, for example, 4mm or 6mm.

[0038] In this embodiment, the ceramic shell 2 is provided with a first convex-concave structure 22, and the ceramic riser tube 5 is provided with a second convex-concave structure 53, and the first convex-concave structure 22 and the second convex-concave structure 53 are engaged.

[0039] In this embodiment, the first convex-concave structure 22 includes a first convex ring and a first annular groove, and the second convex-concave structure 53 includes a second convex ring and a second annular groove. The first convex ring engages with the second annular groove, and the first annular groove engages with the second convex ring.

[0040] According to another aspect of the present invention, a self-sealing method for anti-gravity investment casting molten metal is provided, using the above-described anti-gravity investment casting molten metal self-sealing device, comprising the following steps: S1. The ceramic shell 2 is placed in the sand box 1; S2, sealing ring 3 and partition plate 4 are assembled, and ceramic riser tube 5 is placed on sealing ring 3 and in the center hole of partition plate 4; S3. The ceramic shell 2 is placed on the ceramic riser tube 5 and the assembly is completed; S4. Cooling medium is introduced into the sealing ring 3; S5. The ceramic riser tube 5 is inserted into the crucible, and the pressure drives the molten metal to rise along the ceramic riser tube 5 to complete the casting filling and solidification.

[0041] As can be seen from the above technical solution, the advantages and positive effects of the anti-gravity investment casting molten metal self-sealing device and method of the present invention are as follows: This invention ensures the assembly accuracy between the ceramic riser tube and the ceramic shell through wedge-shaped guidance and flexible assembly gap, and adopts a cooling and sealing structure to improve the self-sealing effect of molten metal leakage, which greatly improves the safety and reliability of the equipment process.

[0042] In this invention, the ceramic shell 2 and the ceramic riser tube 5 are assembled with flexible guiding function and allow for a certain degree of assembly error; in addition, the sealing ring 3 is water-cooled and has a self-sealing function for metal liquid leakage, which alleviates the problem of sealing high-temperature metal liquid under pressure conditions in the prior art. The device is efficient and simple, and improves production efficiency.

[0043] Those skilled in the art should understand that the specific structures and processes shown in the above detailed embodiments are merely exemplary and not restrictive. Furthermore, those skilled in the art can combine the various technical features described above in various possible ways to form new technical solutions or make other modifications, all of which fall within the scope of this invention.

Claims

1. A counter gravity investment casting metal liquid self-sealing device, characterized in that, It comprises: a sand box containing sand, having a first groove at its opening, and a first inclined surface on the side of the first groove; a ceramic mold shell, which is clamped in the sand box and wrapped in the sand, and has an outer taper surface on the edge of its opening; a sealing ring, which has a tapered through hole inside, a first flat surface, a second inclined surface on the joint edge of the first surface, and a second surface in the form of a circular ring boss, the first surface being opposite to the second surface, the sealing ring containing cooling medium, the first surface being matched with the first groove, the second inclined surface being matched with the first inclined surface, and the tapered through hole being matched with the outer taper surface; a middle partition plate, which is provided with a second groove, and elastically connected with the circular ring boss, the load bearing surface of the middle partition plate abutting against the sealing ring and the bottom of the sand box, and the middle partition plate having a mounting through hole; a ceramic riser, which is in the form of a cylinder, and has a mounting boss at its head, the mounting boss being clamped between the middle partition plate and the ceramic mold shell, and the outer edge abutting against the tapered through hole, and the central hole of the ceramic riser being communicated with the opening of the ceramic mold shell.

2. The anti-gravity investment casting metal liquid self-sealing device according to claim 1, characterized in that: Springs are clamped between the second groove and the circular ring boss.

3. The anti-gravity investment casting metal liquid self-sealing device according to claim 2, characterized in that: The number of the springs is 3-8, and they are arranged in a circular central symmetry.

4. A counter gravity investment cast metal liquid self-sealing device according to claim 2 or 3, characterized in that: The side gap between the second groove and the circular ring boss is 1-5 mm.

5. The anti-gravity investment casting metal-liquid self-sealing device according to claim 1, characterized in that: The sealing ring is in the form of a hollow structure, and has an inlet and an outlet.

6. The anti-gravity investment casting metal liquid self-sealing device according to claim 5, characterized in that: The gap between the sealing ring and the top surface of the circular ring boss is 2-8 mm.

7. The anti-gravity investment casting metal-liquid self-sealing device according to claim 1, characterized in that: The gap between the outer diameter of the ceramic riser and the mounting through hole is larger than the side gap between the second groove and the circular ring boss.

8. The anti-gravity investment casting metal-liquid self-sealing device according to claim 1, characterized in that: The ceramic mold shell is provided with a first convex-concave structure, and the ceramic riser is provided with a second convex-concave structure, the first convex-concave structure and the second convex-concave structure being clamped and matched.

9. The anti-gravity investment casting metal-liquid self-sealing device according to claim 8, characterized in that: The first convex-concave structure comprises a first convex ring and a first ring groove, and the second convex-concave structure comprises a second convex ring and a second ring groove, the first convex ring being matched with the second ring groove, and the first ring groove being matched with the second convex ring.

10. A method of self-sealing of a metal melt against gravity die casting, characterized in that: The anti-gravity permanent mold casting metal liquid self-sealing device according to any one of claims 1-9 is used, comprising the following steps: S1, clamping the ceramic mold shell in the sand box; S2, assembling the sealing ring and the middle partition plate, and placing the ceramic riser in the sealing ring and the central hole of the middle partition plate; S3, placing the ceramic mold shell on the ceramic riser and completing the assembly; S4, introducing the cooling medium into the sealing ring; S5, inserting the ceramic riser into the crucible, and driving the metal liquid to rise along the ceramic riser under pressure to complete the casting of the casting and solidification.

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