A sealing and heat-insulating multifunctional flange plate for installation of a liquid-lifting pipe in anti-gravity casting

Abstract

The application relates to a sealing and heat-insulating multifunctional flange plate for a liquid lifting pipe used in anti-gravity casting. The flange plate is composed of an end part and a neck part. The end part is located on the upper end of the neck part and forms an annular interface structure. An annular groove is formed on the upper surface of the end part to install a graphite sealing ring. The neck part is divided into a straight cylinder section, an inclined surface section and a platform section from top to bottom. The sealing problem of the liquid lifting pipe passage between a smelting chamber and a mold chamber in anti-gravity casting can be solved, effective pressure difference between the two chambers can be ensured during mold filling, and metal liquid can smoothly fill the mold. The liquid lifting pipe can be accurately positioned during installation, the upper port of the liquid lifting pipe can be prevented from being misaligned with the inlet of the mold cavity, the mold can be prevented from being washed and eroded, and the metal liquid flow can be prevented from being turbulent, so that the service life of the mold and the metallurgical quality of the casting are improved. The heat-insulating problem of the liquid lifting pipe from preheating completion to mold filling completion is improved, the temperature loss speed is slowed down, the flowability of the metal liquid is ensured, and the forming quality and performance of the casting are improved.

Description

Technical Field

[0001] This invention relates to a multi-functional flange for installing, sealing, and insulating riser pipes in anti-gravity casting. Background Technology

[0002] Anti-gravity casting, a unique casting method, utilizes external pressure to force molten metal to rise against gravity through a riser tube into a mold, where it solidifies under controlled pressure. It is widely used in aerospace, automotive manufacturing, and many other fields where high-quality castings are required. Typically, an anti-gravity casting apparatus consists of a melting chamber, a mold chamber, and a partition plate, etc. Figure 1 As shown in the diagram. In this casting process, after the metal is melted in the melting chamber, the molten metal needs to be guided to the mold chamber through the riser pipe to achieve filling. Several key issues urgently need to be addressed in this process. First is the sealing problem. During the filling stage, the melting chamber and the mold chamber must maintain a complete seal, especially the riser pipe channel. If air leakage occurs, the necessary pressure difference ΔP cannot be established between the two chambers. This pressure difference is the key driving force for the molten metal to fill the mold; if the pressure difference cannot be established, the molten metal cannot fill the mold as expected, which will directly lead to casting failure and seriously affect production efficiency and casting output. Currently, although the industry recognizes the importance of sealing the riser pipe channel, there is still a lack of efficient and reliable sealing solutions, making it difficult to guarantee the sealing effect, becoming a major bottleneck restricting the development of anti-gravity casting technology.

[0003] Secondly, there is the issue of installation and positioning. During mold filling, the upper end of the riser pipe must be precisely matched and connected to the mold cavity inlet. However, in the actual installation of the riser pipe and mold, if effective positioning measures are lacking, misalignment between the upper end of the riser pipe and the mold cavity inlet is very likely to occur. This misalignment will lead to a series of adverse consequences. On the one hand, the molten high-temperature metal will erode the mold, greatly shortening its service life and increasing production costs. On the other hand, it may also cause instability at the front end of the molten metal flow during filling, resulting in turbulence, which in turn can lead to quality problems such as air entrapment and slag inclusions, seriously reducing the metallurgical quality of the casting and failing to meet the stringent quality requirements of high-end fields.

[0004] Another issue is the insulation of the riser pipe. The fluidity of molten metal during rising and filling is closely related to temperature. In most cases, the riser pipe needs to be preheated to a specific temperature depending on the alloy being smelted. However, the current challenge is that the temperature of the riser pipe dissipates rapidly between the completion of preheating and the completion of filling. This rapid temperature drop reduces the fluidity of the molten metal, leading to incomplete filling, cold shuts in the casting, and other defects, significantly affecting the molding quality and performance of the casting. Although some research has addressed the insulation of the riser pipe, a mature and effective insulation technology solution has not yet been developed, failing to meet actual production needs. Summary of the Invention

[0005] This invention addresses a series of issues related to the sealing, limiting, and heat preservation of the riser pipe in the anti-gravity casting process by providing a multi-functional flange for sealing and heat preservation of the riser pipe in anti-gravity casting.

[0006] This invention discloses a multi-functional flange for installing, sealing, and insulating riser pipes in anti-gravity casting, comprising an end and a neck. The end is located at the upper end of the neck, forming an annular interface structure. The upper surface of the end is machined with an annular groove for installing a graphite sealing ring. The neck is divided into a straight section, an inclined section, and a stepped section from top to bottom. The angle between the inclined surface of the inclined section and the vertical direction is α. The outer diameter of the straight section is D1, the inner diameter of the straight section is D2, the inner diameter of the bottom end of the inclined section is D4, and the inner diameter of the stepped section is D5; where D4 > D5.

[0007] Advantages of this invention:

[0008] This invention solves the sealing problem of the riser pipe channel between the melting chamber and the mold chamber in anti-gravity casting, ensuring an effective pressure difference between the two chambers during filling and guaranteeing smooth molten metal filling. It achieves precise positioning of the riser pipe during installation, preventing misalignment between the upper end of the riser pipe and the mold cavity inlet, avoiding mold erosion and turbulent molten metal flow, thus improving mold life and casting metallurgical quality. It also improves the heat preservation of the riser pipe from preheating to filling completion, slowing down temperature loss, ensuring molten metal fluidity, and improving casting quality and performance. Furthermore, it allows for the installation of riser pipes of different diameters, achieving multi-purpose functionality and significantly reducing casting production costs. Attached Figure Description

[0009] Figure 1 A schematic diagram of a multi-functional flange for installing a sealing and heat-insulating riser pipe in anti-gravity casting.

[0010] Figure 2 This is a schematic diagram of the riser tube described in Example 1;

[0011] Figure 3 A general schematic diagram showing the installation of the mold, riser pipe, and flange.

[0012] Figure 4 This is a schematic diagram of the riser pipe described in Example 2;

[0013] Figure 5 This is a schematic diagram showing the placement of the partition plate and sealing material on the device. Detailed Implementation

[0014] Specific Implementation Method 1: This implementation method is described in conjunction with the accompanying drawings. This implementation method provides a multi-functional flange for installing, sealing, and insulating riser pipes in anti-gravity casting, consisting of an end portion 1 and a neck portion 2. The end portion 1 forms an annular interface structure at the upper end of the neck portion 2. An annular groove 3 is machined on the upper surface of the end portion 1 for installing a graphite sealing ring 10. The neck portion 2 is divided from top to bottom into a straight cylindrical section 21, an inclined section 22, and a stepped section 23. The angle between the inclined surface of the inclined section 22 and the vertical direction is α. The outer diameter of the straight cylindrical section 21 is D1, the inner diameter of the straight cylindrical section 21 is D2, the inner diameter of the bottom end of the inclined section 22 is D4, and the inner diameter of the stepped section 23 is D5; where D4 > D5.

[0015] This implementation method is simple in design and easy to manufacture. At the same time, the high positioning accuracy avoids the molten high-temperature metal liquid from eroding the mold, thus improving the mold life. It also avoids the instability of the front end of the molten metal liquid entering the cavity inlet, which leads to turbulence and improves the metallurgical quality of the casting.

[0016] In this embodiment, refractory insulation cotton is filled between the riser pipe and the flange cylinder to ensure that the melt in the riser pipe solidifies last. This facilitates the continuous application of pressure to the molten metal in the cavity through the riser pipe until the molten metal in the cavity is completely solidified, thereby improving the feeding effect of the casting, reducing the number of shrinkage cavities and shrinkage porosity, and improving the quality of the casting.

[0017] This flange can be used for the installation and sealing of riser pipes of different diameters, making it a multi-purpose flange that can significantly reduce casting costs.

[0018] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: the end portion 1 has bolt connection holes 12 aligned with corresponding holes in the mold 5, and the end portion 1 and the mold 5 are fastened together by bolts; the lower end of the riser pipe 6 is inserted into the molten metal in the crucible 7, used to guide the molten metal 8 in the crucible 7 into the cavity 9 under the action of anti-gravity; the inclined section 22 limits the riser pipe 6; the part of the riser pipe 6 connected to the flange 4 is covered with refractory insulation cotton 11; the upper end of the riser pipe 6 is sealed to the inlet of the cavity 9 by a graphite sealing ring 10. Everything else is the same as in Specific Implementation Method One.

[0019] In this embodiment, the graphite sealing ring can be replaced with asbestos rope. The above materials have good sealing performance and can effectively fill the gap between the riser pipe and the mold cavity inlet, prevent gas leakage, and ensure that the melting chamber and the mold chamber remain sealed during the filling stage. This ensures that the necessary pressure difference ΔP to push the molten metal into the mold can be established between the two chambers, avoiding casting process failure due to gas leakage.

[0020] This embodiment uses bolt fixing, which further ensures the relative positional accuracy between the riser pipe and the mold. During filling, it maintains the correct connection between the upper end of the riser pipe and the mold cavity inlet, preventing problems such as molten metal erosion of the mold and instability at the front end of the molten metal flow caused by misalignment. This improves the metallurgical quality of the casting and extends the service life of the mold.

[0021] In this embodiment, the portion connecting the riser pipe to the flange is covered with refractory insulation cotton. The refractory insulation cotton has excellent thermal insulation properties, effectively reducing heat loss from the riser pipe during the period from preheating to filling completion, slowing down the rate of temperature decrease in the riser pipe, and allowing the molten metal to maintain good fluidity. This avoids defects such as poor molten metal fluidity, incomplete filling, and cold shuts in the casting caused by rapid temperature drops, thus improving the molding quality and performance of the casting.

[0022] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One in that the value of α is 10–30°. Everything else is the same as in Specific Implementation Method One.

[0023] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method Two in that the riser pipe 6 has a segmented structure that is wider at the top and narrower at the bottom. The outer diameter of the upper segment is d2, the inner diameter of the upper segment is d1, and the outer diameter of the lower segment is d3. Everything else is the same as in Specific Implementation Method Two.

[0024] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method Four in that the outer diameter d2 of the upper section is controlled between D4 and D5. Everything else is the same as in Specific Implementation Method Four.

[0025] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method Four in that the outer diameter d2 of the upper section is controlled within... Everything else is the same as in Specific Implementation Method Four.

[0026] The beveled structure provides excellent guidance, facilitating the installation of the riser pipe and preventing damage caused by friction between the outer surface of the riser pipe and the inner wall of the flange, especially for more fragile ceramic riser pipes. Furthermore, when the outer diameter d2 of the riser pipe is within the specified range, the beveled surface at the bottom of the flange can completely limit the riser pipe, ensuring a precise match and connection between the upper end of the riser pipe and the mold cavity inlet, preventing misalignment.

[0027] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Two in that the riser tube 6 has a three-section structure, narrow at both ends and wide in the middle. The outer diameter of the narrow section is b3, the inner diameter of the narrow section is b1, and the outer diameter of the middle section is b2. Everything else is the same as in Specific Implementation Method Two.

[0028] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Seven in that the outer diameter b3 of the intermediate section is controlled between D4 and D5. Everything else is the same as in Specific Implementation Method Seven.

[0029] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Method Seven in that the outer diameter b3 of the intermediate section is controlled within... Everything else is the same as in Specific Implementation Method Seven.

[0030] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Method Two in that: after the mold 5, riser pipe 6, and flange 4 are installed, the entire assembly is transferred into the mold chamber; then, the upper and lower tanks of the device begin to be vacuumed simultaneously. After the vacuum requirements are met, the riser pipe 6 begins to preheat, and at the same time, the lower tank begins to melt the material; after the material melting is completed and the riser pipe preheating is completed, the mold 5 descends as a whole. At this time, the straight cylinder of the flange 4 will pass through the middle partition plate 13 on the device, the inner diameter of the middle partition plate 13 being D. 3， Ensure D1 < D3; simultaneously, the lower surface of the upper end of flange 4 is completely pressed against the graphite sealing ring 10 placed on the middle partition 13, at which point the upper and lower tanks are completely isolated, and then the lower tank is vented or the upper tank is vented to complete the liquid raising and filling. Other aspects are the same as in specific implementation method two.

[0031] The beneficial effects of the present invention are verified through the following embodiments:

[0032] Example 1: A multi-functional flange for installing, sealing, and insulating riser pipes in anti-gravity casting consists of an end 1 and a neck 2. The end 1 is located at the upper end of the neck 2, forming an annular interface structure. An annular groove 3 is machined on the upper surface of the end 1 for installing a graphite sealing ring 10. The neck 2 is divided into a straight section 21, an inclined section 22, and a stepped section 23 from top to bottom. The angle between the inclined surface of the inclined section 22 and the vertical direction is α. The outer diameter of the straight section 21 is D1, the inner diameter of the straight section 21 is D2, the inner diameter of the bottom end of the inclined section 22 is D4, and the inner diameter of the stepped section 23 is D5. D4 > D5.

[0033] The end portion 1 is provided with bolt connection holes 12 that are aligned with the corresponding holes in the mold 5, and the end portion 1 and the mold 5 are fastened together by bolts; the lower end of the riser pipe 6 is inserted into the molten metal in the crucible 7, and is used to guide the molten metal in the crucible 7 into the cavity 9 under the action of anti-gravity; the inclined section 22 limits the riser pipe 6; the part of the riser pipe 6 connected to the flange 4 is covered with refractory insulation cotton 11; the upper end of the riser pipe 6 is sealed to the inlet of the cavity 9 by a graphite sealing ring 10;

[0034] The value of α is between 10 and 30°; the riser pipe 6 has a segmented structure that is wider at the top and narrower at the bottom, with the outer diameter of the upper segment being d2, the inner diameter of the upper segment being d1, and the outer diameter of the lower segment being d3; the outer diameter d2 of the upper segment is controlled between D4 and D5; this bevel facilitates the installation of the riser pipe (guiding function) and can prevent damage to the riser pipe (especially ceramic riser pipes) due to friction between the outer surface of the riser pipe and the inner wall of the flange. Furthermore, the outer diameter d2 of the riser pipe is maintained at... At this time, the inclined surface at the bottom of the flange can completely limit the riser pipe. Then, the upper mold and the upper end of the flange (with a graphite sealing ring placed in the groove) are fastened together with bolts. This ensures optimal sealing and matching between the riser pipe inlet and the mold cavity inlet. The upper end of the riser pipe is connected to the mold cavity inlet via a graphite sealing ring. See the overall installation diagram below. Figure 4 This approach serves two purposes: firstly, it prevents the molten metal from eroding the mold; secondly, it avoids instability at the front end of the molten metal flow entering the cavity, thus preventing turbulence and improving the metallurgical quality of the casting.

[0035] In addition, since the fluidity of molten metal during liquid lifting and filling is closely related to temperature, the riser pipe usually needs to be preheated (the preheating temperature depends on the smelting alloy, but should not exceed 900℃ to prevent the stainless steel flange from softening). However, if the riser pipe is not properly insulated after preheating, its temperature will drop rapidly. Filling the space between the flange and the riser pipe (above the flange bevel; without this bevel, a right-angle flange cannot guarantee precise positioning between the riser pipe installation and the refractory insulation cotton placement) with refractory insulation cotton can minimize the rate of temperature drop when the riser pipe is immersed in the molten metal in the crucible after preheating, reduce the temperature difference with the molten metal, and prevent some riser pipes with poor thermal shock resistance from cracking when immersed in the molten metal, causing filling failure. Meanwhile, good insulation of the riser tube during filling ensures that the melt inside the riser tube solidifies last. This maximizes the advantages of the anti-gravity casting process, which continuously applies pressure to the molten metal in the mold cavity through the riser tube until the molten metal in the mold cavity is completely solidified, improving the feeding effect of the casting, reducing the number of shrinkage cavities and shrinkage holes, and improving the quality of the casting.

[0036] Example 2: This example differs from Example 1 in that: when the inner diameter and wall thickness of the riser tube are small, the riser tube 6 has a three-section structure that is narrow at both ends and wide in the middle. The outer diameter of the narrow section is b3, the inner diameter of the narrow section is b1, and the outer diameter of the middle section is b3; the outer diameter b3 of the middle section is controlled between D4 and D5; the outer diameter b3 of the middle section is controlled within... This flange accommodates the installation and use requirements of various riser pipe diameters, achieving multiple uses with a single flange and significantly reducing the production cost of castings. Everything else is the same as in Example 1.

[0037] After the mold 5, riser pipe 6, and flange 4 are installed, the entire assembly is moved into the mold chamber. Then, the upper and lower tanks of the device are simultaneously evacuated. Once the vacuum requirements are met, the riser pipe 6 begins preheating, and the lower tank begins material melting. After the material melting is complete and the riser pipe preheating is finished, the mold 5 descends as a whole. At this point, the straight flange 4 will pass through the partition plate 13 on the device, the inner diameter of which is D. 3， Ensure that D1 < D3; at the same time, the lower surface of the upper end of the flange 4 is completely pressed against the graphite sealing ring 10 placed on the middle partition 13. At this time, the upper and lower tanks are completely isolated. Then, the lower tank is vented or the upper tank is vented to complete the liquid lifting and filling.

Claims

1. A multi-functional flange plate for installation of a riser for counter-gravity casting, characterized in that The flange plate is composed of an end part (1) and a neck part (2); the end part (1) is located on the upper end of the neck part (2) to form an annular interface structure, and an annular groove (3) is formed on the upper surface of the end part (1) to install a graphite sealing ring (10); the neck part (2) is divided into a straight cylinder segment (21), an inclined surface segment (22) and a platform segment (23) from top to bottom; the angle between the inclined surface of the inclined surface segment (22) and the vertical direction is α; the outer diameter of the straight cylinder segment (21) is D1, the inner diameter of the straight cylinder segment (21) is D2, the inner diameter of the bottom end of the inclined surface segment (22) is D4, and the inner diameter of the platform segment (23) is D5; D4>D5; The end part (1) is provided with bolt connecting holes (12) which are aligned with the corresponding hole positions of the mold (5), and the end part (1) is tightly connected with the mold (5) through bolts; the lower end of the liquid lifting pipe (6) is inserted into the metal liquid (8) in the crucible (7) to guide the metal liquid in the crucible (7) into the cavity (9) under the action of anti-gravity; the inclined surface segment (22) limits the liquid lifting pipe (6); the part of the liquid lifting pipe (6) connected with the flange plate (4) is covered with refractory insulation cotton (11); the upper end of the liquid lifting pipe (6) and the inlet of the cavity (9) are sealingly connected through the graphite sealing ring (10).

2. The multi-functional flange plate for installation of a liquid-lifting pipe for counter-gravity casting, according to claim 1, characterized in that The value of α is 10-30°.

3. The multi-functional sealing and heat-insulating flange plate for installation of a liquid-lifting pipe for counter-gravity casting according to claim 1, characterized in that The liquid lifting pipe (6) is a segmented structure with wide upper part and narrow lower part, the outer diameter of the upper part is d2, and the inner diameter of the upper part is d1, and the outer diameter of the lower part is d3.

4. The multi-functional flange plate for installation of a liquid-lifting pipe for counter-gravity casting, according to claim 3, characterized in that The outer diameter d2 of the upper part is controlled between D4 and D5.

5. The multi-functional sealing and heat-insulating flange plate for installation of a liquid-lifting pipe for counter-gravity casting according to claim 3, characterized in that The outer diameter d2 of the upper section is controlled to be 6. The multi-functional sealing and heat-insulating flange plate for installation of a liquid-lifting pipe for counter-gravity casting according to claim 1, characterized in that The liquid lifting pipe (6) is a three-segment structure with narrow ends and wide middle part, the outer diameter of the narrow segment is b3, the inner diameter of the narrow segment is b1, and the outer diameter of the middle segment is b2.

7. The multi-functional flange plate for installation of a liquid-lifting pipe for counter-gravity casting, according to claim 6, characterized in that The outer diameter b3 of the middle segment is controlled between D4 and D5.

8. The multi-functional flange plate for installation of a liquid-lifting pipe for counter-gravity casting, according to claim 6, wherein The outer diameter b3 of the intermediate section is controlled to be 9. The multi-functional flange plate for installation of a liquid-lifting pipe for counter-gravity casting, according to claim 1, characterized in that After the installation of the mold (5), the liquid-lifting pipe (6) and the flange plate (4) is completed, the whole is transferred into the mold chamber; then the upper and lower pots of the device start to synchronously pump vacuum, after meeting the vacuum requirement, the liquid-lifting pipe (6) starts to preheat, and at the same time the lower pot starts to smelt the material; after the material is melted and the liquid-lifting pipe preheating is completed, the mold (5) as a whole is lowered, at this time the straight cylinder of the flange plate (4) will pass through the middle partition plate (13) on the device, the inner diameter of the middle partition plate (13) is D 3， Ensure that D1 < D3; at the same time, the lower surface of the upper end of the flange plate (4) completely presses the graphite sealing ring (10) placed on the middle partition plate (13), at this time the upper and lower pots are completely isolated, then the lower pot is filled with gas or the upper pot is exhausted to complete the liquid lifting and mold filling.

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