Anti-gravity investment casting device and casting method suitable for titanium alloy

Abstract

The present invention provides a counter-gravity investment casting device and a casting method suitable for titanium alloys, belonging to the field of titanium alloy casting, and solves the sealing problem of existing counter-gravity forming devices and the problem that the riser tube and the runner inlet of the mold shell cannot be aligned. Among them, the lifting structure can drive the mold assembly to move in the vertical direction. The mold shell in the mold assembly is located in a sand box, and the sand box abuts the top surface of the flange sleeve. The flange sleeve is slidably penetrated through the mold bracket, and the upper pressure plate abuts the top of the sand box and is connected to the mold bracket. The water-cooled copper crucible is located below the riser tube, and the upper end of the riser tube is provided with a flange structure. The positioning and centering structure is used to make the runner inlet of the mold shell coaxial with the riser tube. The sealing structure includes a first sealing ring and a second sealing ring. The first sealing ring is located between the flange sleeve and the flange structure, and the second sealing ring is located between the flange sleeve and the middle partition. The device can align the runner inlet of the mold shell with the riser tube, and the lower working tank is completely sealed.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium alloy casting, and in particular relates to a counter-gravity investment casting device suitable for titanium alloy and a casting method thereof. Background Art

[0002] In the prior art, patent publication number CN103934431B discloses a device and method for counter-gravity forming of complex thin-walled castings of titanium and titanium alloys. This device aims to address key issues, such as the inability of the forming device to achieve the high-inert environment melting required for counter-gravity forming of titanium and titanium alloys. The device specifically discloses an upper tank body, a middle septum, a lower tank body, a hydraulic ejector, a power supply, a tiltable heating coil, a crucible, a vacuum system, a liquid level adjustment system, a circulating water cooling system, a smelting observation mechanism, a tamping mechanism, a feeding mechanism, a temperature measurement mechanism, a riser, a hydraulic drive system, a mold lifting system, a mold, and a spare mold. The upper and lower tank bodies are separated by a middle septum. The upper tank body is equipped with a mold lifting system, and the mold and riser are located within the mold lifting system. The lower tank body is equipped with a tiltable heating coil, a crucible, and a spare mold. The riser has a flat flange at the top that fits into a hole in the bottom of the mold, providing a tight seal between the upper tank body and the middle septum, and between the middle septum and the lower tank body. The patent application with application publication number CN117961029A discloses a vacuum low-pressure investment casting method for high-temperature alloys, which specifically discloses: a flange-like structure is provided at the uppermost end of the riser tube, which is arranged exactly on the low-pressure casting platform for placing the hole connecting the sand box and the smelting device, and a high-temperature sealing gasket is also provided between the flange-like structure at the uppermost end of the riser tube and the flange-like structure at the lower part of the mold shell.

[0003] However, these existing anti-gravity forming devices still have sealing problems. When the lower working tank is inflated, gas may leak from between the lower working tank and the sand box. In addition, there is a problem that the riser tube and the runner inlet of the mold shell cannot be aligned. The riser tube and the runner inlet of the mold shell are easily misaligned, causing turbulence of the titanium alloy melt at the runner inlet of the mold shell, resulting in metallurgical defects such as air entrapment and inclusions in the casting. Summary of the Invention

[0004] In view of this, in order to solve the sealing problem of the existing counter-gravity forming device and the problem that the riser tube and the runner inlet of the mold shell cannot be aligned, the present invention proposes a counter-gravity investment casting device suitable for titanium alloy and a casting method thereof.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A counter-gravity investment casting device suitable for titanium alloys, comprising:

[0007] Upper working tank, the bottom of which is provided with a middle partition;

[0008] The mold assembly is located in the upper working tank. The mold assembly includes an upper pressure plate, a sand box, a mold shell, a flange sleeve and a mold bracket. The mold shell is located in the sand box. The runner inlet of the mold shell is provided through the bottom through hole at the bottom center of the sand box. The sand box abuts against the top surface of the flange sleeve. The flange sleeve is slidably provided on the mold bracket. The upper pressure plate abuts against the top of the sand box. The upper pressure plate and the mold bracket are detachably connected. The bottom surface of the flange sleeve can abut against the middle partition plate.

[0009] A lifting structure is used to drive the mold assembly to move in a vertical direction;

[0010] The lower working tank is located below the upper working tank and is connected to the middle partition;

[0011] A water-cooled copper crucible and an induction coil are both located in the lower working tank, and the induction coil is arranged around the water-cooled copper crucible;

[0012] A rising pipe, a communicating hole is provided in the center of the flange sleeve, the rising pipe is passed through the communicating hole, a flange structure is provided at the upper end of the rising pipe, the rising pipe can be passed through the middle partition, the water-cooled copper crucible is located below the rising pipe, and the pouring channel inlet of the mold shell is located above the rising pipe;

[0013] A positioning and centering structure is used to arrange the runner inlet of the mold shell and the riser pipe coaxially;

[0014] The sealing structure includes a first sealing ring and a second sealing ring. The first sealing ring is located between the flange sleeve and the flange structure, and the second sealing ring is located between the flange sleeve and the middle partition.

[0015] As a preferred solution of the above-mentioned anti-gravity investment casting device suitable for titanium alloy, the positioning and centering structure includes a positioning base plate, a frustum, a plurality of positioning stops, a plurality of guide stops, and a sink groove arranged at the center of the top surface of the flange sleeve and connected to the communicating hole. The frustum is detachably arranged on the positioning base plate, and the plurality of positioning stops are fixedly arranged on the positioning base plate. The plurality of positioning stops are spaced around the frustum. When the sand box is placed on the positioning base plate, the plurality of positioning stops abut against the outer wall of the sand box. When the mold shell is placed in the sand box, the frustum is penetrated through the runner inlet of the mold shell, so that the runner inlet of the mold shell can be coaxially arranged with the sand box.

[0016] The flange structure is embedded in the sink, so that the riser pipe and the flange sleeve can be coaxially arranged;

[0017] Multiple guide blocks are fixed and spaced apart on the mold bracket. When the flange sleeve is placed on the mold bracket and the sand box is placed on the flange sleeve, the multiple guide blocks all abut against the outer wall of the flange sleeve and the outer wall of the sand box, so that the flange sleeve and the sand box can be coaxially arranged.

[0018] As a preferred solution of the above-mentioned counter-gravity investment casting device suitable for titanium alloys, the guide block is provided with a guide surface, which can guide the flange sleeve to be installed on the mold bracket and can guide the sand box to be placed above the flange sleeve.

[0019] As a preferred solution of the above-mentioned anti-gravity investment casting device suitable for titanium alloys, the bottom surface of the sink is provided with a first sealing groove, the first sealing ring is embedded in the first sealing groove, the middle partition is provided with a second sealing groove, and the second sealing ring is embedded in the second sealing groove.

[0020] As a preferred solution of the above-mentioned anti-gravity investment casting device suitable for titanium alloys, the top surface of the flange structure is provided with a third sealing groove, and a third sealing ring is embedded in the third sealing groove. The third sealing ring can seal the gap between the sand box and the flange structure.

[0021] As a preferred solution of the above-mentioned counter-gravity investment casting device suitable for titanium alloys, the inner diameter of the third sealing ring is smaller than the aperture of the bottom through hole of the sand box.

[0022] As a preferred solution of the above-mentioned anti-gravity investment casting device suitable for titanium alloys, water glass sand is filled between the inner wall of the sand box and the outer wall of the mold shell, and water glass sand is filled between the outer wall of the runner inlet of the mold shell and the inner wall of the bottom through hole of the sand box.

[0023] As a preferred solution of the above-mentioned counter-gravity investment casting device suitable for titanium alloys, the diameter of the bottom through hole of the sand box is 2 to 3 times the diameter of the runner inlet of the mold shell.

[0024] As a preferred solution of the above-mentioned counter-gravity investment casting device suitable for titanium alloys, the diameter of the lowermost end of the communicating hole of the flange sleeve is equal to the inner diameter of the middle partition.

[0025] As a preferred solution of the above-mentioned anti-gravity investment casting device suitable for titanium alloys, the lifting structure includes a synchronous motor and a screw transmission structure. The synchronous motor is fixedly arranged on the upper working tank. The input end and the output end of the screw transmission structure are respectively connected to the synchronous motor and the mold support. The synchronous motor drives the mold assembly to move in the vertical direction through the screw transmission structure.

[0026] As a preferred solution of the above-mentioned anti-gravity investment casting device suitable for titanium alloys, the sand box includes a cylindrical box body, an upper cover and a lower plate, the upper cover is connected to the upper end of the cylindrical box body by bolts, and the lower plate is connected to the lower end of the cylindrical box body by bolts.

[0027] The present invention also provides a counter-gravity investment casting method applicable to titanium alloys, which uses the above-mentioned counter-gravity investment casting device applicable to titanium alloys, comprising:

[0028] S1: Connect the mold bracket to the lifting structure, install the flange sleeve on the mold bracket, install the liquid riser on the flange sleeve, and use the positioning and centering structure to set the liquid riser and the flange sleeve coaxially;

[0029] S2: By positioning the centering structure, the runner inlet of the mold shell is set coaxially with the sand box;

[0030] S3: Fill the sand box with water glass sand to fix the position of the mold shell in the sand box;

[0031] S4: Perform CO2 blowing and hardening operation on the mold shell and water glass sand, and let it stand for a set time;

[0032] S5: Place the flask in a preheating furnace to preheat the flask and mold shell;

[0033] S6: The flask is transferred to the upper working tank and placed above the flange sleeve. The flask and the flange sleeve are coaxially arranged through the positioning and centering structure, so that the riser tube and the runner inlet of the mold shell are coaxially arranged;

[0034] S7: placing the upper pressing plate on the sand box and connecting it to the mold support to fix the position of the sand box;

[0035] S8: Perform vacuum operation on the upper working tank and the lower working tank;

[0036] S9: heating the riser pipe by a riser pipe preheating device;

[0037] S10: melting the titanium alloy material in a water-cooled copper crucible;

[0038] S11: Determine whether the titanium alloy material in the water-cooled copper crucible has been melted;

[0039] If yes, proceed to S12;

[0040] If not, return to S10;

[0041] S12: The lifting structure drives the mold assembly to move downward, and the lower end of the liquid riser is inserted into the water-cooled copper crucible;

[0042] S13: Perform filling operation.

[0043] As a preferred solution of the above-mentioned counter-gravity investment casting method for titanium alloy, the positioning and centering structure includes a positioning base plate, a frustum, and a plurality of positioning blocks. In S2, the runner inlet of the mold shell is coaxially arranged with the sand box through the positioning and centering structure, which includes:

[0044] The sand box is placed on the positioning base plate, and multiple positioning blocks are in contact with the outer wall of the sand box to limit the position of the sand box. At this time, the frustum is passed through the bottom through hole of the sand box;

[0045] The mold shell is placed in the sand box, and the frustum is penetrated through the runner inlet of the mold shell to define the position of the mold shell, so that the runner inlet of the mold shell is coaxially arranged with the sand box.

[0046] As a preferred solution of the above-mentioned anti-gravity investment casting method for titanium alloys, the lifting structure in S12 drives the mold assembly to move downward, including:

[0047] When the bottom surface of the flange sleeve contacts the middle partition, the lifting structure continues to drive the mold bracket to descend a set distance. At this time, the upper pressure plate, sand box and mold bracket descend together, and the flange sleeve does not move, which can squeeze the sealing structure to achieve complete sealing.

[0048] As a preferred solution of the above-mentioned anti-gravity investment casting method suitable for titanium alloys, filling the sand box with water glass sand in S3 includes: when the height of the casting is less than the set height, the water glass sand covers the mold shell, and a metal tube is provided on the mold shell, the metal tube is connected to the exhaust hole of the mold shell, and the mold shell is exhausted through the metal tube.

[0049] Compared with the prior art, the present invention provides a counter-gravity investment casting device and a casting method for titanium alloys, which have the following beneficial effects:

[0050] (1) The present invention provides a counter-gravity investment casting device suitable for titanium alloys and a casting method thereof. The counter-gravity investment casting device suitable for titanium alloys is provided with a positioning and centering structure, which can completely center the runner inlet of the mold shell and the riser, that is, the runner inlet of the mold shell and the riser are coaxially arranged, and the runner inlet of the mold shell coincides with the center line of the riser, thereby avoiding turbulence of the titanium alloy melt at the runner inlet of the mold shell due to misalignment of the riser and the runner inlet of the mold shell, resulting in metallurgical defects such as air entrapment and inclusions in the casting.

[0051] (2) The present invention provides a counter-gravity investment casting device suitable for titanium alloys and a casting method thereof. The counter-gravity investment casting device suitable for titanium alloys is provided with a sealing structure that can completely seal the lower working tank. When the lower working tank is inflated, the lower working tank needs to remain completely sealed so that the titanium alloy melt in the water-cooled copper crucible can be pushed up along the riser pipe by increasing the air pressure in the lower working tank. The first sealing ring is located between the flange sleeve and the flange structure to prevent the gas in the lower working tank from escaping along the gap between the riser pipe and the middle partition, the gap between the riser pipe and the flange sleeve, the gap between the flange structure and the flange sleeve, and the gap between the flange sleeve and the sand box. The second sealing ring is located between the flange sleeve and the middle partition, which can prevent the gas in the lower working tank from escaping along the gap between the riser pipe and the middle partition, and the gap between the middle partition and the flange sleeve, thereby preventing the upper working tank and the lower working tank from cross-gasing when the lower working tank is fed with air to establish a filling pressure difference, resulting in filling failure.

[0052] (3) The present invention provides a counter-gravity investment casting device and a casting method for titanium alloys. The counter-gravity investment casting device for titanium alloys adopts a water-cooled copper crucible (also called a water-cooled copper crucible induction shell furnace smelting) to smelt the titanium alloy. The inner wall of the water-cooled copper crucible is generally 400-500°C, and the molten titanium melt is about 1700°C. Due to the temperature gradient between the molten titanium melt and the inner wall of the water-cooled copper crucible, a shell of a certain thickness is formed on the outer surface of the titanium melt, which can avoid the pollution problem of the titanium alloy melt caused by using other ceramic crucibles to melt the titanium alloy, and can greatly ensure the metallurgical quality of the casting. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0054] Figure 1 It is a partial structural schematic diagram of a counter-gravity investment casting device for titanium alloys provided by a specific embodiment of the present invention;

[0055] Figure 2 yes Figure 1 Enlarged view of point A in the middle;

[0056] Figure 3 yes Figure 1 Enlarged view of point B in the middle;

[0057] Figure 4 1 is a schematic structural diagram of a counter-gravity investment casting device for titanium alloys provided in a specific embodiment of the present invention;

[0058] Figure 5It is a partial structural schematic diagram of a positioning and centering structure of a counter-gravity investment casting device for titanium alloys provided by a specific embodiment of the present invention;

[0059] Figure 6 This is an assembly diagram of a mold support, a flange sleeve, and a riser tube in a counter-gravity investment casting device for titanium alloys provided by a specific embodiment of the present invention;

[0060] Figure 7 This is an assembly diagram of a mold support, a flange sleeve, a riser tube, and a sand box in a counter-gravity investment casting device for titanium alloys provided by a specific embodiment of the present invention;

[0061] Figure 8 1 is a schematic structural diagram of a riser tube in a counter-gravity investment casting device for titanium alloys provided by a specific embodiment of the present invention;

[0062] Figure 9 It is a top view of a middle partition plate in a counter-gravity investment casting device suitable for titanium alloys provided in a specific embodiment of the present invention.

[0063] In the picture:

[0064] 1. Upper working tank;

[0065] 2. Lower the working tank;

[0066] 3. Mold assembly; 31. Sand box; 32. Mold shell; 33. Flange sleeve; 34. Mold bracket; 311. Upper cover; 312. Cylindrical box; 313. Lower plate; 331. Connecting hole; 321. Runner inlet; 322. Metal pipe;

[0067] 4. Lifting structure;

[0068] 5. Riser pipe; 51. Flange structure;

[0069] 6. Water-cooled copper crucible;

[0070] 7. Middle partition;

[0071] 81. Positioning base plate; 82. Round table; 83. Positioning stopper; 84. Guide stopper; 841. Guide surface;

[0072] 91. First sealing ring; 92. Second sealing ring;

[0073] 10. The third sealing ring;

[0074] 11. The third sealing groove;

[0075] 12. Riser pipe preheating device. DETAILED DESCRIPTION

[0076] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features therein can be combined with each other in the absence of conflict, and the embodiments described are only part of the embodiments of the present invention, not all of the embodiments.

[0077] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0078] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0079] In the description of this embodiment, terms such as "upper," "lower," and "right" are used to refer to positions or locations based on the positions or locations shown in the accompanying drawings. These terms are intended solely to facilitate description and simplify operation, and are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meaning.

[0080] See also Figure 1-9Describe this embodiment. The present invention provides a counter-gravity investment casting device suitable for titanium alloys and a casting method thereof. The counter-gravity investment casting device suitable for titanium alloys includes an upper working tank 1, a mold assembly 3, a lifting structure 4, a lower working tank 2, a water-cooled copper crucible 6, an induction coil, a rising pipe 5, a positioning and centering structure and a sealing structure. A middle partition 7 is provided at the bottom of the upper working tank 1. The lower working tank 2 is located below the upper working tank 1 and is connected to the middle partition 7. The mold assembly 3 is located in the upper working tank 1. The mold assembly 3 includes an upper pressure plate, a sand box 31, a mold shell 32, a flange sleeve 33 and a mold bracket 34. The mold shell 32 is located in the sand box 31. The runner inlet 321 of the mold shell 32 is penetrated through the bottom through hole at the bottom center of the sand box 31. The sand box 31 abuts against the top surface of the flange sleeve 33. The flange sleeve 33 is slidably penetrated through the mold bracket 34. The upper pressure plate abuts against the top of the sand box 31. The plate is detachably connected to the mold bracket 34, the bottom surface of the flange sleeve 33 can abut against the middle partition 7, the lifting structure 4 is used to drive the mold assembly 3 to move in the vertical direction, the water-cooled copper crucible 6 and the induction coil are both located in the lower working tank 2, and the induction coil is arranged around the water-cooled copper crucible 6. A connecting hole 331 is provided in the center of the flange sleeve 33, and the rising liquid pipe 5 is passed through the connecting hole 331. The rising liquid pipe 5 can be passed through the middle partition 7, and a flange structure 51 is provided at the upper end of the rising liquid pipe 5. The water-cooled copper crucible 6 is located below the rising liquid pipe 5, and the runner inlet 321 of the mold shell 32 is located above the rising liquid pipe 5. The positioning and centering structure is used to make the runner inlet 321 of the mold shell 32 coaxial with the rising liquid pipe 5. The sealing structure includes a first sealing ring 91 and a second sealing ring 92. The first sealing ring 91 is located between the flange sleeve 33 and the flange structure 51, and the second sealing ring 92 is located between the flange sleeve 33 and the middle partition 7.

[0081] In this anti-gravity investment casting apparatus for titanium alloys, the lower working tank 2 serves as the smelting chamber, and a water-cooled copper crucible 6 within the lower working tank 2 is used to melt the titanium alloy. Before smelting is completed, the lifting structure 4 drives the mold support 34 to be positioned above the upper working tank 1. The riser tube 5 and mold assembly 3 are first installed, and during installation, the riser tube 5 and the runner inlet 321 of the mold shell 32 are aligned using a positioning and centering structure. After smelting is completed, the lifting structure 4 drives the installed mold assembly 3 downward, and the riser tube 5 passes through the middle partition 7 and enters the water-cooled copper crucible 6. By inflating and pressurizing the lower working tank 2, the increasing air pressure within the lower working tank 2 propels the titanium alloy melt within the water-cooled copper crucible 6 up the riser tube 5 into the mold shell 32, performing the mold filling operation. During the inflation of the lower working tank 2, the lower working tank 2 must remain completely sealed to ensure that the increased air pressure in the lower working tank 2 can propel the titanium alloy melt within the water-cooled copper crucible 6 up the riser tube 5. The first sealing ring 91 is located between the flange sleeve 33 and the flange structure 51 to prevent the gas in the lower working tank 2 from escaping through the gaps between the riser tube 5 and the middle diaphragm 7, the gaps between the riser tube 5 and the flange sleeve 33, the gaps between the flange structure 51 and the flange sleeve 33, and the gaps between the flange sleeve 33 and the sand box 31. The second sealing ring 92 is located between the flange sleeve 33 and the middle diaphragm 7 to prevent the gas in the lower working tank 2 from escaping through the gaps between the riser tube 5 and the middle diaphragm 7, and the gaps between the middle diaphragm 7 and the flange sleeve 33. Thus, the sealing structure can completely seal the lower working tank 2, preventing cross-flow of gas between the upper and lower working tanks 1 and 2, which could cause filling failure when the lower working tank 2 is fed with air to establish a filling pressure differential. A positioning and centering structure is used to completely align the runner inlet 321 of the mold shell 32 with the riser tube 5, that is, the runner inlet 321 of the mold shell 32 and the riser tube 5 are coaxially arranged, and the runner inlet 321 of the mold shell 32 coincides with the center line of the riser tube 5, thereby avoiding turbulence of the titanium alloy melt at the runner inlet 321 of the mold shell 32 due to misalignment of the riser tube 5 and the runner inlet 321 of the mold shell 32, resulting in metallurgical defects such as air entrainment and inclusions in the casting. In addition, a water-cooled copper crucible 6 (also called a water-cooled copper crucible 6 induction shell furnace smelting) is used to smelt the titanium alloy. The inner wall of the water-cooled copper crucible 6 is generally 400-500°C, and the molten titanium melt is about 1700°C. Due to the temperature gradient between the molten titanium melt and the inner wall of the water-cooled copper crucible 6, a shell of a certain thickness is formed on the outer surface of the titanium melt, which can avoid the pollution problem of the titanium alloy melt caused by using other ceramic crucibles to melt the titanium alloy, and can greatly ensure the metallurgical quality of the casting.

[0082] like Figure 5-7As shown, optionally, the positioning and centering structure includes a positioning base plate 81, a circular table 82, a plurality of positioning blocks 83, a plurality of guide blocks 84, and a sink arranged at the center of the top surface of the flange sleeve 33 and connected to the connecting hole 331. The circular table 82 is detachably arranged on the positioning base plate 81, and the plurality of positioning blocks 83 are fixedly arranged on the positioning base plate 81. The plurality of positioning blocks 83 are spaced around the circular table 82. When the sand box 31 is placed on the positioning base plate 81, the plurality of positioning blocks 83 abut against the outer wall of the sand box 31. When the mold shell 32 is placed in the sand box 31, the circular table 82 is detachably arranged on the positioning base plate 81. The plurality of positioning blocks 83 are fixedly arranged on the positioning base plate 81. The plurality of positioning blocks 83 are spaced around the circular table 82. When the sand box 31 is placed on the positioning base plate 81, the plurality of positioning blocks 83 abut against the outer wall of the sand box 31. When the mold shell 32 is placed in the sand box 31, the circular table 82 is detachably arranged on the positioning base plate 81. The platform 82 is provided through the runner inlet 321 of the mold shell 32, which can make the runner inlet 321 of the mold shell 32 and the sand box 31 coaxially arranged; the flange structure 51 is embedded in the sink, which can make the riser pipe 5 and the flange sleeve 33 coaxially arranged; multiple guide blocks 84 are fixed and arranged at intervals on the mold bracket 34. When the flange sleeve 33 is placed on the mold bracket 34 and the sand box 31 is placed on the flange sleeve 33, the multiple guide blocks 84 all abut against the outer wall of the flange sleeve 33 and the outer wall of the sand box 31, which can make the flange sleeve 33 and the sand box 31 coaxially arranged.

[0083] By arranging the runner inlet 321 of the mold shell 32 coaxially with the flask 31, the riser pipe 5 coaxially with the flange sleeve 33, and the flange sleeve 33 coaxially with the flask 31, the runner inlet 321 of the mold shell 32 is aligned with the riser pipe 5, that is, the centerline of the runner inlet 321 of the mold shell 32 coincides with the centerline of the riser pipe 5. This prevents misalignment between the riser pipe 5 and the runner inlet 321 of the mold shell 32, which would otherwise cause the high-temperature titanium alloy melt to flush the mold shell 32 and cause turbulence in the titanium alloy melt at the runner inlet 321 of the mold shell 32, leading to metallurgical defects such as air entrapment and inclusions in the casting.

[0084] The outer surface of the mold shell 32 is very rough. After the mold shell 32 is placed in the flask 31, the bottom surface of the mold shell 32 does not fit in the flask 31. Therefore, after the mold shell 32 is naturally placed in the flask 31, it is impossible to ensure that the runner inlet 321 of the mold shell 32 is aligned with the flask 31, that is, the runner inlet 321 of the mold shell 32 coincides with the center line of the flask 31. In this embodiment, the runner inlet 321 of the mold shell 32 is aligned with the flask 31 using a positioning base 81, a round table 82, and multiple positioning blocks 83. After the flask 31 is placed on the positioning base 81, the multiple positioning blocks 83 abut against the outer wall of the flask 31, thereby limiting the position of the flask 31 and preventing the flask 31 from shaking when it is lifted, which could damage the mold shell 32. It is understood that the runner inlet 321 of the mold shell 32 is a cylindrical structure. The mold shell 32 is then placed in the flask 31. The runner inlet 321 of the mold shell 32 is mounted on the truncated cone 82, which can limit the runner inlet 321 of the mold shell 32. It is understood that the truncated cone 82 is located at the center of the circle formed by the plurality of positioning blocks 83, so that the runner inlet 321 of the mold shell 32 is aligned with the flask 31. The truncated cone 82 is detachably mounted on the positioning base plate 81. The size of the runner inlet 321 of the mold shell 32 will vary depending on the casting. Based on the diameter of the runner inlet 321 of the mold shell 32, a truncated cone 82 of appropriate size is selected and mounted on the positioning base plate 81. Optionally, the diameter of the truncated cone 82 is 0.5 to 1 mm smaller than the diameter of the runner inlet 321 of the mold shell 32, and the height of the truncated cone 82 is lower than the height of the runner inlet 321 of the mold shell 32.

[0085] The flange structure 51 is embedded in the trough, enabling the riser tube 5 to be coaxially arranged with the flange sleeve 33. In this embodiment, the outer diameter of the flange structure 51 at the upper end of the riser tube 5 is 0.5-1 mm smaller than the inner diameter of the trough of the flange sleeve 33, thereby aligning the riser tube 5 with the flange sleeve 33.

[0086] Multiple guide blocks 84 are fixed and spaced apart on the mold support 34. When the flange sleeve 33 is placed on the mold support 34 and the flask 31 is placed on the flange sleeve 33, the multiple guide blocks 84 abut the outer wall of the flange sleeve 33 and the outer wall of the flask 31, ensuring that the flange sleeve 33 and the flask 31 are coaxial. During testing, the flange sleeve 33 is not allowed to shift and must be fully positioned. The multiple guide blocks 84 abut the outer wall of the flange sleeve 33 to limit the flange sleeve 33. The multiple guide blocks 84 also abut the outer wall of the flask 31 to limit the flange sleeve 33, ensuring that the flange sleeve 33 and the flask 31 are aligned, i.e., the centerline of the flange sleeve 33 coincides with the centerline of the flask 31. In this embodiment, the outer diameter of the flask 31 is equal to the outer diameter of the upper end of the flange sleeve 33.

[0087] Optionally, the guide block 84 has a guide surface 841, which can guide the flange sleeve 33 to be installed on the mold support 34 and can guide the flask 31 to be placed above the flange sleeve 33. It is understandable that the guide surface 841 is provided on the side of the guide block 84 close to the flask 31.

[0088] like Figure 1-3 As shown, optionally, a first sealing groove is provided on the bottom surface of the sink, into which a first sealing ring 91 is embedded. The middle partition 7 is provided with a second sealing groove, into which a second sealing ring 92 is embedded. The first sealing groove and the second sealing groove respectively limit the positions of the first sealing ring 91 and the second sealing ring 92. After being respectively embedded in the first sealing groove and the second sealing ring 92, the first sealing ring 91 and the second sealing ring 92 still protrude from the first sealing groove and the second sealing groove by 2-3 mm. The first sealing ring 91 and the second sealing ring 92 are both graphite sealing rings, with an outer diameter and inner diameter difference of 10-20 mm.

[0089] like Figure 1 、 Figure 2 and Figure 8 As shown, the top surface of the flange structure 51 optionally includes a third sealing groove 11, within which a third sealing ring 10 is embedded. The third sealing ring 10 can seal the gap between the flask 31 and the flange structure 51. The third sealing groove 11 limits the position of the third sealing ring 10. Because the bottom surface of the runner inlet 321 of the mold shell 32 is also very rough and cannot be level, during the liquid filling stage, when the molten high-temperature titanium alloy passes between the riser tube 5 and the runner inlet 321 of the mold shell 32, it may flow into the gap on both sides under the action of pressure. The third sealing ring 10 can seal the gap between the flask 31 and the flange structure 51 to prevent the molten high-temperature titanium alloy from passing through. Optionally, the inner diameter of the third sealing ring 10 is smaller than the aperture of the bottom through-hole of the flask 31. This prevents the molten high-temperature titanium alloy from eroding the flask 31 or even damaging it.

[0090] Optionally, the outer diameter of the third sealing groove 11 is smaller than the outer diameter of the flange sleeve 33 to prevent the third sealing ring 10 from warping and deforming when the flange sleeve 33 is pressed downward.

[0091] Optionally, water glass sand is filled between the inner wall of the flask 31 and the outer wall of the mold shell 32, and between the outer wall of the runner inlet 321 of the mold shell 32 and the inner wall of the bottom through hole of the flask 31. The water glass sand not only serves to secure the mold shell 32 but also serves to insulate the mold shell 32 and the runner inlet 321 of the mold shell 32, thereby reducing temperature loss, facilitating the filling of the titanium alloy melt, and significantly improving the yield rate of titanium alloy castings produced by counter-gravity casting.

[0092] Optionally, the diameter of the bottom through hole of the sand box 31 is 2 to 3 times the diameter of the runner inlet 321 of the mold shell 32. To ensure sequential solidification of the titanium alloy casting, that is, the counter-gravity casting solidifies from top to bottom, a certain thickness of water glass sand is required at the runner inlet 321 of the mold shell 32 to provide thermal insulation. This ensures that the runner inlet 321 of the mold shell 32 solidifies last and continuously provides pressure for shrinkage compensation of the casting, thereby improving the metallurgical quality of the titanium alloy casting.

[0093] The riser pipe 5 has poor impact resistance and is easily damaged. In this embodiment, the diameter of the communication hole 331 gradually increases in the vertical upward direction. This can reduce the collision between the riser pipe 5 and the upper side of the flange sleeve 33 during installation, thereby preventing the riser pipe 5 from colliding with the flange sleeve 33.

[0094] Specifically, the angle α between the inner wall of the communicating hole 331 of the flange sleeve 33 and the bottom surface of the flange sleeve 33 is 10-30°.

[0095] Optionally, the diameter of the lowermost end of the communicating hole 331 of the flange sleeve 33 is equal to the inner diameter of the middle partition plate 7. This facilitates the complete centering of the flange sleeve 33 and the middle partition plate 7 when the flange sleeve 33 is installed.

[0096] Optionally, the lifting structure 4 includes a synchronous motor and a screw drive structure. The synchronous motor is fixedly mounted on the upper working tank 1. The input and output ends of the screw drive structure are respectively connected to the synchronous motor and the mold support 34. The synchronous motor drives the mold assembly 3 in a vertical direction through the screw drive structure. The specific structure of the screw drive structure belongs to the prior art and will not be described in detail here. A flange sleeve 33 is provided within the mold assembly 3 to reduce the length of the screw drive structure. The length of the screw drive structure is sufficient to allow the lower end of the flange sleeve 33 to abut against the middle partition 7 before the mold support 34 is lowered a set distance.

[0097] Optionally, the flask 31 comprises a cylindrical body 312, an upper cover 311, and a lower plate 313. The upper cover 311 is bolted to the upper end of the cylindrical body 312, and the lower plate 313 is bolted to the lower end of the cylindrical body 312. To achieve sequential solidification and installation requirements, the lower plate 313 of the flask 31 can be replaced with a suitable bottom through-hole diameter based on the size of the runner inlet 321 of the mold shell 32. To accommodate different castings, the bottom through-hole diameter and the truncated cone 82 in the centering structure of the lower plate 313 of the flask 31 can be customized to suit the casting, facilitating dimensional adjustment and significantly reducing the production cost of titanium alloy castings. Optionally, the upper cover 311 is equipped with lifting lugs.

[0098] The present invention also provides a counter-gravity investment casting method applicable to titanium alloys, which uses the above-mentioned counter-gravity investment casting device applicable to titanium alloys, comprising:

[0099] S1: Connect the mold support 34 to the lifting structure 4, install the flange sleeve 33 on the mold support 34, and install the liquid riser 5 on the flange sleeve 33. Using the positioning and centering structure, the liquid riser 5 and the flange sleeve 33 are coaxially arranged. Specifically, the flange structure 51 at the upper end of the liquid riser 5 is embedded in the recessed groove of the flange sleeve 33. The center line of the flange structure 51 coincides with the center line of the liquid riser 5, and the center line of the recessed groove coincides with the center line of the flange sleeve 33, thereby aligning the liquid riser 5 and the flange sleeve 33.

[0100] S2: By positioning the centering structure, the runner inlet 321 of the mold shell 32 is coaxially arranged with the flask 31. Specifically, by positioning the bottom plate 81, the round table 82 and a plurality of positioning blocks 83, the runner inlet 321 of the mold shell 32 can be coaxially arranged with the flask 31.

[0101] Specifically, the sand box 31 is placed on the positioning base plate 81, and multiple positioning blocks 83 are all in contact with the outer wall of the sand box 31 to limit the position of the sand box 31. At this time, the cone 82 is passed through the bottom through hole of the sand box 31; the mold shell 32 is placed in the sand box 31, and the cone 82 is passed through the runner inlet 321 of the mold shell 32 to limit the position of the mold shell 32, so that the runner inlet 321 of the mold shell 32 is coaxially arranged with the sand box 31.

[0102] S3: Fill the flask 31 with water glass sand to secure the mold shell 32 in place. Optionally, when the casting height is less than the set height, the water glass sand covers the mold shell 32. A metal tube 322 is provided on the mold shell 32, connecting it to the vent holes in the mold shell 32 for exhaust from the mold shell 32. When filling the flask 31 with water glass sand, the vent holes in the mold shell 32 must be covered to prevent the water glass sand from entering the mold shell 32. The water glass sand is made of quartz sand or reclaimed sand, with a particle size of 70-140 mesh. The water glass is sodium water glass, with a modulus of 2.0-2.3 in summer and 2.6-2.9 in winter; its density is 1.3-1.7 g / cm³. The mass ratio of water glass to quartz sand is approximately 5%-8%. After thoroughly mixing the water glass and quartz sand, fill the flask 31, gradually compacting the mixture. The filling height of the water glass sand depends on the height of the casting. When the height of the casting is less than 10 cm and the height of the runner inlet 321 of the mold shell 32 is 2~3 cm, the water glass sand needs to completely cover the mold shell 32 to prevent the high-temperature titanium alloy melt from pushing the mold shell 32 at a high filling speed, causing filling failure. At this time, the exhaust hole of the mold shell 32 is blocked with a metal tube 322, and the mold shell 32 is exhausted through the metal tube 322; when the height of the casting is greater than 10 cm, the filling height of the water glass sand can be lower than the exhaust hole. At this time, the exhaust hole can be simply covered with aluminum foil, etc., and only a gap needs to be left for exhaust.

[0103] S4: Perform a CO2 air-blow hardening operation on the mold shell 32 and the water glass sand, and let it stand for a set time. After the water glass sand is filled, create air-blow channels inside and around the mold shell 32. Then, blow CO2 gas at a pressure of 0.1-0.3 MPa for 30-60 seconds. After the blowing is completed, let it stand for 30 minutes to allow the CO2 gas to fully diffuse. After the CO2 air-blow hardening operation and standing, the water glass sand has a certain strength to support the mold shell 32 and keep it in place. Furthermore, the mold shell 32 is not strong and easily damaged. The CO2 air-blow hardening operation hardens the mold shell 32 and the water glass sand without applying external force to the mold shell 32, preventing damage to the mold shell 32.

[0104] Since the water glass sand between the mold shell 32 and the sand box 31 has been hardened, the position of the mold shell 32 relative to the sand box 31 no longer changes, so the sand box 31 is separated from the positioning base plate 81, and the runner inlet 321 of the mold shell 32 is separated from the frustum 82. The frustum 82 remains on the positioning base plate 81, and the position of the mold shell 32 relative to the sand box 31 remains unchanged. After that, only the sand box 31 and the mold shell 32 are transferred.

[0105] S5: Place the flask 31 in a preheating furnace to preheat the flask 31 and the mold shell 32. Specifically, after resting, the flask 31 is placed in the preheating furnace and dried at 200-400°C for 4 hours. The temperature in the furnace is then raised to the preheating temperature of the mold shell 32 and kept at this temperature for another 2 hours until the flask 31 and the mold shell 32 reach the preheating temperature.

[0106] S6: The flask 31 is transferred into the upper working tank 1 and placed above the flange sleeve 33. Using the positioning and centering structure, the flask 31 and the flange sleeve 33 are coaxially arranged, thereby aligning the riser pipe 5 with the runner inlet 321 of the mold shell 32. The riser pipe 5 and the flange sleeve 33 were already coaxially arranged in S1, and the runner inlet 321 of the mold shell 32 was already coaxially arranged in S2. Therefore, by aligning the flask 31 and the flange sleeve 33 in S6, the riser pipe 5 and the runner inlet 321 of the mold shell 32 can be coaxially arranged.

[0107] S7: Place the upper pressing plate on top of the flask 31 and connect it to the mold support 34 to fix the position of the flask 31. Use the lifting lugs to transfer the preheated flask 31 to the flange sleeve 33. Then install the upper pressing plate on top of the flask 31 and fix it to the mold support 34 with bolts. Apply pre-tightening force to the flask 31 until the upper pressing plate is fully tightened.

[0108] S8: Vacuum the upper working tank 1 and the lower working tank 2. The lower working tank 2 is vacuumed to the vacuum degree required for titanium alloy smelting.

[0109] S9: The riser pipe 5 is heated by the riser pipe preheating device 12. The riser pipe preheating device 12 is located in the upper working tank 1 and has an open state and a closed state. When the riser pipe 5 needs to be heated, the riser pipe preheating device 12 is controlled to be in the closed state, at which time the riser pipe preheating device 12 wraps around the riser pipe 5 and can heat the riser pipe 5. When the riser pipe 5 does not need to be heated, the riser pipe preheating device 12 is controlled to be in the open state, at which time the riser pipe 5 is separated from the riser pipe preheating device 12.

[0110] S10: The water-cooled copper crucible 6 is used to melt the titanium alloy material.

[0111] S11: Determine whether the titanium alloy material in the water-cooled copper crucible 6 has been melted;

[0112] If yes, proceed to S12;

[0113] If not, return to S10;

[0114] S12: The lifting structure 4 drives the mold assembly 3 downward, and the lower end of the liquid riser 5 is inserted into the water-cooled copper crucible 6. Before the titanium alloy material in the water-cooled copper crucible 6 of the lower working tank 2 melts, the synchronous motor drives the screw transmission structure to raise the mold assembly 3 to the highest point. After the titanium alloy material in the water-cooled copper crucible 6 of the lower working tank 2 melts and enters the liquid lifting and mold filling stage, the synchronous motor drives the screw transmission structure to lower the mold assembly 3 and the liquid riser 5 to the lowest point. The liquid riser 5 is synchronously inserted into the titanium alloy melt in the water-cooled copper crucible 6. At this time, the flange sleeve 33 will press on the middle partition 7.

[0115] Optionally, after the bottom surface of the flange sleeve 33 abuts the middle partition 7, the lifting structure 4 continues to drive the mold support 34 to descend a set distance. At this time, the upper pressure plate, the sand box 31 and the mold support 34 descend together, and the flange sleeve 33 does not move, which can squeeze the sealing structure to achieve complete sealing. When the flange sleeve 33 presses on the middle partition 7, the lifting structure 4 drives the mold assembly 3 and the liquid riser 5 to descend a set distance. In this embodiment, the set distance is 5mm. At this time, the flange sleeve 33 has already abutted against the middle partition 7, so the position of the flange sleeve 33 remains unchanged. The upper pressure plate is connected to the mold support 34, and the lifting structure 4 drives the mold support 34 to descend. The mold support 34 slides relative to the flange sleeve 33, so that the upper pressure plate and the sand box 31 descend together with the mold support 34, and will squeeze the first sealing ring 91, the second sealing ring 92 and the third sealing ring 10 again to achieve complete isolation, that is, the seal is completely in place. The first and second sealing rings 91, 92 prevent cross-flow between the upper and lower working tanks 1 and 2, which could cause filling failure, when the lower working tank 2 introduces air to establish a filling pressure differential. The third sealing ring 10 prevents the molten high-temperature titanium alloy from passing through the gap between the flask 31 and the flange structure 51, thus preventing the molten high-temperature titanium alloy from eroding or even damaging the flask 31.

[0116] S13: Perform the mold filling operation. After the mold filling is completed, the flange sleeve 33 does not need to be removed. Only the riser tube 5 needs to be replaced to proceed with the next casting. After the flask 31 is moved above the flange sleeve 33, only the upper pressure plate needs to be installed to complete the installation of the mold assembly 3. The entire process is convenient and efficient, and a completely sealed state can be achieved, ensuring smooth mold filling operation.

[0117] Obviously, the embodiments of the present invention disclosed above are intended only to help illustrate the present invention. The embodiments do not describe all details in detail, nor do they limit the present invention to specific embodiments. Numerous modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. It is not necessary and impossible to list all embodiments here.

Claims

1. A counter-gravity investment casting device suitable for titanium alloys, characterized in that: include: An upper working tank (1), wherein a middle partition plate (7) is provided at the bottom of the upper working tank (1); A mold assembly (3) is located in the upper working tank (1). The mold assembly (3) includes an upper pressing plate, a sand box (31), a mold shell (32), a flange sleeve (33) and a mold support (34). The mold shell (32) is located in the sand box (31). A runner inlet (321) of the mold shell (32) is provided through a bottom through hole at the bottom center of the sand box (31). The sand box (31) abuts against the top surface of the flange sleeve (33). The flange sleeve (33) is slidably provided through the mold support (34). The upper pressing plate abuts against the upper side of the sand box (31). The upper pressing plate and the mold support (34) are detachably connected. The bottom surface of the flange sleeve (33) can abut against the middle partition (7). A lifting structure (4), the lifting structure (4) is used to drive the mold assembly (3) to move in a vertical direction; A lower working tank (2), the lower working tank (2) is located below the upper working tank (1) and is connected to the middle partition (7); A water-cooled copper crucible (6) and an induction coil, wherein the water-cooled copper crucible (6) and the induction coil are both located in the lower working tank (2), and the induction coil is arranged around the water-cooled copper crucible (6); A rising pipe (5), a communicating hole (331) is provided at the center of the flange sleeve (33), the rising pipe (5) is passed through the communicating hole (331), a flange structure (51) is provided at the upper end of the rising pipe (5), the rising pipe (5) can be passed through the middle partition (7), the water-cooled copper crucible (6) is located below the rising pipe (5), and the pouring channel inlet (321) of the mold shell (32) is located above the rising pipe (5); A positioning and centering structure, the positioning and centering structure is used to arrange the runner inlet (321) of the mold shell (32) and the riser (5) coaxially; The sealing structure comprises a first sealing ring (91) and a second sealing ring (92). The first sealing ring (91) is located between the flange sleeve (33) and the flange structure (51), and the second sealing ring (92) is located between the flange sleeve (33) and the middle partition (7).

2. The anti-gravity investment casting device for titanium alloy according to claim 1, characterized in that: The positioning and centering structure includes a positioning base plate (81), a truncated cone (82), a plurality of positioning blocks (83), a plurality of guide blocks (84), and a sink arranged at the center of the top surface of the flange sleeve (33) and connected to the connecting hole (331); the truncated cone (82) is detachably arranged on the positioning base plate (81); the plurality of positioning blocks (83) are all fixedly arranged on the positioning base plate (81); the plurality of positioning blocks (83) are spaced around the truncated cone (82); when the sand box (31) is placed on the positioning base plate (81), the plurality of positioning blocks (83) are all in contact with the outer wall of the sand box (31); when the mold shell (32) is placed in the sand box (31), the truncated cone (82) is passed through the runner inlet (321) of the mold shell (32), so that the runner inlet (321) of the mold shell (32) can be coaxially arranged with the sand box (31); The flange structure (51) is embedded in the sink, so that the riser pipe (5) and the flange sleeve (33) can be coaxially arranged; A plurality of guide blocks (84) are fixed and spaced apart on the mold support (34). When the flange sleeve (33) is placed on the mold support (34) and the sand box (31) is placed on the flange sleeve (33), the plurality of guide blocks (84) all abut against the outer wall of the flange sleeve (33) and the outer wall of the sand box (31), so that the flange sleeve (33) and the sand box (31) can be coaxially arranged.

3. The anti-gravity investment casting device for titanium alloy according to claim 2, characterized in that: The guide block (84) is provided with a guide surface (841) capable of guiding the flange sleeve (33) to be installed on the mold support (34) and guiding the flask (31) to be placed above the flange sleeve (33).

4. The anti-gravity investment casting device for titanium alloy according to claim 2, characterized in that: The bottom surface of the sink is provided with a first sealing groove, the first sealing ring (91) is embedded in the first sealing groove, the middle partition (7) is provided with a second sealing groove, the second sealing ring (92) is embedded in the second sealing groove.

5. The anti-gravity investment casting device for titanium alloy according to claim 1, characterized in that: A third sealing groove (11) is provided on the top surface of the flange structure (51), a third sealing ring (10) is embedded in the third sealing groove (11), and the third sealing ring (10) can seal the gap between the sand box (31) and the flange structure (51).

6. The anti-gravity investment casting device for titanium alloy according to claim 5, characterized in that: The inner diameter of the third sealing ring (10) is smaller than the aperture of the bottom through hole of the sand box (31).

7. The anti-gravity investment casting device for titanium alloy according to claim 1, characterized in that: Water glass sand is filled between the inner wall of the sand box (31) and the outer wall of the mold shell (32), and water glass sand is filled between the outer wall of the runner inlet (321) of the mold shell (32) and the inner wall of the bottom through hole of the sand box (31).

8. The anti-gravity investment casting device for titanium alloy according to claim 1, characterized in that: The aperture of the bottom through hole of the sand box (31) is 2 to 3 times the aperture of the runner inlet (321) of the mold shell (32).

9. The anti-gravity investment casting device for titanium alloy according to claim 1, characterized in that: The hole diameter of the lowermost end of the communicating hole (331) of the flange sleeve (33) is equal to the inner diameter of the middle partition plate (7).

10. The anti-gravity investment casting device for titanium alloy according to claim 1, characterized in that: The lifting structure (4) includes a synchronous motor and a screw transmission structure. The synchronous motor is fixedly arranged on the upper working tank (1). The input end and the output end of the screw transmission structure are respectively connected to the synchronous motor and the mold support (34). The synchronous motor drives the mold assembly (3) to move in the vertical direction through the screw transmission structure.

11. The anti-gravity investment casting device for titanium alloy according to claim 1, characterized in that: The sand box (31) includes a cylindrical box body (312), an upper cover (311) and a lower plate (313), wherein the upper cover (311) is connected to the upper end of the cylindrical box body (312) by bolts, and the lower plate (313) is connected to the lower end of the cylindrical box body (312) by bolts.

12. A counter-gravity investment casting method for titanium alloys, characterized by: The anti-gravity investment casting device for titanium alloys according to any one of claims 1 to 11 comprises: S1: Connect the mold support (34) to the lifting structure (4), install the flange sleeve (33) on the mold support (34), install the liquid riser (5) on the flange sleeve (33), and arrange the liquid riser (5) and the flange sleeve (33) coaxially through the positioning and centering structure; S2: The runner inlet (321) of the mold shell (32) is coaxially arranged with the sand box (31) by positioning the centering structure; S3: Filling the sand box (31) with water glass sand to fix the position of the mold shell (32) in the sand box (31); S4: Performing a CO2 blowing hardening operation on the mold shell (32) and the water glass sand, and leaving them to stand for a set time; S5: placing the flask (31) in a preheating furnace to preheat the flask (31) and the mold shell (32); S6: The sand box (31) is transferred to the upper working tank (1) and placed above the flange sleeve (33). The sand box (31) and the flange sleeve (33) are coaxially arranged through the positioning and centering structure, so that the riser (5) and the runner inlet (321) of the mold shell (32) are coaxially arranged; S7: placing the upper pressing plate above the flask (31) and connecting it to the mold support (34) to fix the position of the flask (31); S8: performing a vacuum operation on the upper working tank (1) and the lower working tank (2); S9: heating the riser tube (5) by the riser tube preheating device (12); S10: melting the titanium alloy material in a water-cooled copper crucible (6); S11: Determine whether the titanium alloy material in the water-cooled copper crucible (6) has been melted; If yes, proceed to S12; If not, return to S10; S12: The lifting structure (4) drives the mold assembly (3) to move downward, and the lower end of the liquid riser (5) is inserted into the water-cooled copper crucible (6); S13: Perform filling operation.

13. The anti-gravity investment casting method for titanium alloy according to claim 12, characterized in that: The positioning and centering structure includes a positioning base plate (81), a truncated cone (82) and a plurality of positioning blocks (83). The process of S2 for coaxially arranging the runner inlet (321) of the mold shell (32) and the sand box (31) through the positioning and centering structure includes: The sand box (31) is placed on the positioning base plate (81), and a plurality of positioning blocks (83) are in contact with the outer wall of the sand box (31) to limit the position of the sand box (31). At this time, the round table (82) is passed through the bottom through hole of the sand box (31); The mold shell (32) is placed in the sand box (31), and the frustum (82) is penetrated through the runner inlet (321) of the mold shell (32) to limit the position of the mold shell (32), so that the runner inlet (321) of the mold shell (32) and the sand box (31) are coaxially arranged.

14. The anti-gravity investment casting method for titanium alloy according to claim 12, characterized in that: The lifting structure (4) in S12 drives the mold assembly (3) to move downward, including: When the bottom surface of the flange sleeve (33) contacts the middle partition (7), the lifting structure (4) continues to drive the mold support (34) to descend a set distance. At this time, the upper pressure plate, the sand box (31) and the mold support (34) descend together, and the flange sleeve (33) does not move, which can squeeze the sealing structure to achieve complete sealing.

15. The anti-gravity investment casting method for titanium alloy according to claim 12, characterized in that: In S3, filling the sand box (31) with water glass sand includes: when the height of the casting is less than the set height, the water glass sand covers the mold shell (32), and the mold shell (32) is provided with a metal pipe (322), the metal pipe (322) is connected to the exhaust hole of the mold shell (32), and the mold shell (32) is exhausted through the metal pipe (322).

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