A combined riser for low pressure casting of aluminum alloys and method of making and using the same

Abstract

The application discloses a combined liquid lifting pipe for low-pressure casting of an aluminum alloy, which comprises a liquid lifting lining pipe, the outer periphery of the liquid lifting lining pipe is fixedly connected with a liquid lifting base pipe, the outer periphery of the liquid lifting base pipe is fixedly connected with a liquid lifting sleeve pipe, the material of the liquid lifting base pipe and the liquid lifting sleeve pipe is graphite, and the material of the liquid lifting lining pipe is heat-resistant steel; the combined liquid lifting pipe is connected among components, effectively eliminates the gap between the combined liquid lifting pipe and different materials, and solves the problem that the metal base pipe and the non-metallic protective sheet of the composite material liquid lifting pipe are not combined well.

Description

Technical Field

[0001] This invention relates to the field of casting technology, and in particular to a combined riser pipe for low-pressure casting of aluminum alloys and its manufacturing and usage methods. Background Technology

[0002] Low-pressure casting is a casting method between gravity casting and pressure casting. Low-pressure casting allows for stable filling and solidification under pressure, significantly improving the quality of castings. It is particularly suitable for casting complex aluminum alloy parts. The riser pipe is one of the key components in low-pressure casting, its main function being to guide flow and compensate for shrinkage. Currently used riser pipes are mainly metal riser pipes and ceramic riser pipes. Metal riser pipes have good mechanical properties and excellent airtightness, but they are prone to deformation at high temperatures and the coating is easily peeled off, resulting in a short service life. Ceramic riser pipes are resistant to high temperatures and corrosion, but their mechanical properties are poor, making them easily broken, difficult to manufacture, and costly. There is also research on composite material riser pipes, which use a metal pipe as a skeleton, with non-metallic protective plates embedded inside and outside to protect the metal skeleton from corrosion by the high-temperature casting liquid. However, these composite riser pipes often have poor bonding between the metal skeleton and the non-metallic protective plates, resulting in poor thermal shock resistance and easy damage. Therefore, to fully utilize the advantages of composite material riser pipes in terms of material combination, research on the bonding strength between the metal base pipe and the non-metallic protective plates is extremely important. Summary of the Invention

[0003] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0004] In view of the problems existing in the above and / or existing riser tubes, the present invention is proposed.

[0005] Therefore, the purpose of this invention is to provide a combined riser pipe for low-pressure casting of aluminum alloy. This invention realizes the connection between the components of the combined riser pipe, effectively eliminates the gap between the different materials of the combined riser pipe, and solves the problem of poor bonding between the metal base pipe and the non-metallic protective plate of the composite material riser pipe.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a combined riser pipe for low-pressure casting of aluminum alloy, comprising a riser inner liner, a riser base pipe fixedly connected to the outer periphery of the riser inner liner, and a riser outer sleeve fixedly connected to the outer periphery of the riser base pipe, wherein the riser inner liner and the riser outer sleeve are both made of graphite, and the riser base pipe is made of heat-resistant steel.

[0007] As a preferred embodiment of the combined riser pipe for low-pressure casting of aluminum alloy in this invention, wherein: the upper end of the riser base pipe is fixed with a connecting step, and the outer periphery of the riser base pipe below the connecting step is fixed with an installation step.

[0008] As a preferred embodiment of the combined riser pipe for low-pressure casting of aluminum alloy in this invention, wherein: a plurality of first base pipe pin holes are arranged on the riser base pipe between the connecting step and the mounting step; a plurality of first inner liner pin holes corresponding one-to-one with the first base pipe pin holes are arranged on the riser inner liner pipe; a downwardly extending adapter step is fixed on the riser base pipe below the mounting step; a plurality of second base pipe pin holes are arranged on the riser base pipe below the adapter step; a plurality of sleeve pin holes corresponding one-to-one with the second base pipe pin holes are arranged on the riser outer sleeve; a plurality of second inner liner pin holes corresponding one-to-one with the second base pipe pin holes are arranged on the riser inner liner pipe; the first base pipe pin holes and the corresponding first inner liner pin holes form a first connecting hole; the sleeve pin holes, the corresponding second base pipe pin holes, and the corresponding second inner liner pin holes form a second connecting hole.

[0009] As a preferred embodiment of the combined riser pipe for low-pressure casting of aluminum alloy in this invention, wherein: a first phase change plug is provided at the first connection hole, a second phase change plug is provided at the second connection hole, the riser base pipe is connected to the riser inner liner pipe via the first phase change plug, and the riser outer sleeve pipe, the riser base pipe and the riser inner liner pipe are connected together via a plurality of second phase change plugs.

[0010] As another object of the present invention, the present invention provides a method for preparing a combined riser pipe for low-pressure casting of aluminum alloys, comprising the following steps:

[0011] 1. Processing the riser base pipe;

[0012] 2. Machining the riser liner;

[0013] 3. Machining the riser jacket;

[0014] 4. Assemble the inner riser liner, the base riser, and the outer riser jacket together.

[0015] As a preferred embodiment of the preparation method in this invention, the specific processing steps of step 1 are as follows:

[0016] 101. Heat-resistant steel bars are used, and each surface is rough-machined using a lathe with a 1mm allowance.

[0017] 102. Use a drilling machine and indexing equipment to process the bolt holes arranged in a circular array on the mounting table, as well as the first base pipe pin holes and the second base pipe pin holes arranged in a circular array on the riser base pipe.

[0018] 103. Aging to relieve processing stress;

[0019] 104. When semi-finishing on each surface using a lathe, leave a 0.5mm allowance;

[0020] 105. Quenching treatment;

[0021] 106. Use a turning machine with ceramic cutting tools to finish all surfaces to the required dimensions;

[0022] 107. Surface sandblasting treatment, followed by thorough cleaning and drying;

[0023] 108. Apply heat-resistant coating to the surface using a wet method and then dry.

[0024] As another objective of this invention, this invention provides a method for preparing a combined riser pipe for low-pressure casting of aluminum alloys, wherein the specific processing steps of step 2 are as follows:

[0025] 201. Use graphite tube material and use a lathe to turn the outer diameter and bore the inner end face of the inner hole to ensure that the outer diameter of the riser liner is 0.02-0.04mm smaller than the inner diameter of the riser base tube, and ensure that the total length of the riser liner is equal to that of the riser base tube.

[0026] 2-2. Using a drilling machine and indexing equipment, machine the pin holes on the outer periphery of the riser inner liner pipe. The position and number of these pin holes should correspond to the first and second pin holes on the riser base pipe.

[0027] As another objective of this invention, this invention provides a method for preparing a combined riser pipe for low-pressure casting of aluminum alloys, wherein the specific processing steps of step 3 are as follows:

[0028] 301. Graphite tube material is used. The outer diameter of the inner hole is bored using a turning machine to ensure that the outer diameter of the riser outer tube is smaller than the outer diameter of the matching step, so as to facilitate the installation of the combined riser tube. Ensure that the taper of the tapered hole below the riser outer tube is 45°, and that the bottom diameter of the tapered hole is equal to the inner diameter of the riser inner liner tube.

[0029] 302. Using a drilling machine and indexing equipment, machine the sleeve pin holes on the outer circumference of the lifting outer sleeve, the position and number of which are consistent with the second base pipe pin holes.

[0030] As another objective of this invention, this invention provides a method for preparing a combined riser pipe for low-pressure casting of aluminum alloys. In step 4, the specific assembly process is as follows:

[0031] 401. Install the riser liner into the inner hole of the riser base pipe, making them aligned along their length. Gently rotate the riser liner so that the pin hole on its outer surface is approximately coaxial with the first pin hole and the second pin hole on the base pipe.

[0032] 402. Insert the lifting outer sleeve into the lower end of the lifting base tube until the lifting base tube contacts the bottom surface of the inner hole of the lifting outer sleeve. Gently rotate the lifting outer sleeve so that the sleeve pin hole on its outer surface is approximately coaxial with the pin hole of the second base tube.

[0033] 403. Molten brass is poured into a combination of pin holes consisting of pin holes on the riser outer tube, riser base tube, and riser inner liner tube. After the molten brass cools and solidifies, a first phase change pin and a second phase change pin are formed. The first phase change pin locks the riser base tube and the riser inner liner tube, while the second phase change pin locks the riser outer tube, riser base tube, and riser inner liner tube. During casting, the molten brass also flows into the gaps in the assembly of the riser outer tube, riser base tube, and riser inner liner tube. After cooling, a thin layer of brass is formed.

[0034] 404. Grind the exposed parts of the first and second phase change pins after casting so that they are flush with the outer surface of the ring. Clean up dust and debris, spray a heat-resistant coating on the outer step end face of the first phase change pin, and then dry it.

[0035] As another objective of this invention, a method for preparing a combined riser pipe for low-pressure casting of aluminum alloys is provided. In step 403, a vacuum casting device is used to cast a riser base pipe, a riser outer sleeve, and a riser inner liner pipe together. The vacuum casting device includes a vacuum casting box, with an openable door connected to the front end of the vacuum casting box. A fixed center is fixedly connected to one end of the vacuum casting box in the left-right direction, and a movable center is connected to the other end of the vacuum casting box in the left-right direction. A mandrel is rotatably connected between the fixed center and the movable center. The combined riser pipe is fitted onto the mandrel via the riser inner liner pipe. One end of the mandrel rests against a fixed center in the left-right direction, and the outer circumference of the other end of the mandrel in the left-right direction has external threads. A nut is threaded onto the mandrel via the external threads. The nut presses the liquid-lifting base pipe and the liquid-lifting inner liner pipe tightly onto the liquid-lifting outer sleeve at the upper end of the tapered hole. A transmission screw is rotatably connected to the vacuum casting box above the combined liquid-lifting pipe. A movable plate that is slidably connected to the transmission screw is threaded onto the movable screw and is fixedly connected to the movable plate. A casting pipe is fixedly connected to the movable plate. An upper adapter is fixedly connected to the upper end of the vacuum casting box, and a lower adapter is connected to the upper end of the casting pipe. A connecting hose is fixedly connected between the upper adapter and the lower adapter.

[0036] Compared with existing technologies, this invention has the following technical advantages: it achieves the connection between the components of the combined riser pipe, effectively eliminating the gaps between different materials in the combined riser pipe, and solving the problem of poor bonding between the metal base pipe and the non-metallic protective plate of the composite material riser pipe; the riser pipe formed by vacuum casting has good anti-corrosion molding, and after cooling, a thin layer of brass is formed in the gaps between the components, which effectively supports the riser inner liner and riser outer sleeve assembled on the riser base pipe, resulting in excellent bonding force between the riser base pipe and the riser inner liner and riser outer sleeve, greatly improving the thermal shock resistance of the combined riser pipe, and greatly extending the service life of the combined riser pipe; it can be applied to the low-pressure casting of aluminum alloys. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0038] Figure 1 This is a diagram of the internal structure of the present invention.

[0039] Figure 2 This is a diagram of the internal structure of the liquid-lifting base tube in this invention.

[0040] Figure 3 This is a three-dimensional structural diagram of the liquid-lifting inner liner tube in this invention.

[0041] Figure 4 This is a three-dimensional structural diagram of the liquid-lifting outer jacket in this invention.

[0042] Figure 5 This is a diagram showing the internal structure of the heat preservation furnace when using the present invention.

[0043] Figure 6 for Figure 5 A magnified view of a portion of point A in the middle.

[0044] Figure 7 for Figure 5 A magnified view of a section at point B in the middle.

[0045] Figure 8 Front view of the vacuum casting equipment used to prepare the riser tube.

[0046] Figure 9 Internal structure diagram of the vacuum casting equipment used to prepare the riser tube.

[0047] Figure 10 for Figure 9 A magnified view of a section at point C.

[0048] In the diagram, 100 liters of liquid pipe, 101 liters of liquid outer sleeve, 101a tapered hole, 101b sleeve pin hole, 102 first phase change plug, 103 liters of liquid inner liner, 103a second inner liner pin hole, 103b first inner liner pin hole, 104 liters of liquid base pipe, 104a adapter step, 104a-1 second sealing groove, 104b mounting step, 104b-1 bolt hole, 104b-2 first sealing groove, 104c connecting step, 104d first base pipe pin hole, 104e second base pipe pin hole, 105 second phase change plug, 106 asbestos rope sealing strip, 107 metal sealing strip, 200 heat preservation furnace, 201 crucible 202. Crucible, 202. Cover plate, 203. Compressed air inlet pipe, 300. First fastening screw, 400. Vacuum casting equipment, 401. Viewing window, 402. Door, 403. Compressed air inlet pipe, 404. Upper adapter, 405. Vacuum gauge, 406. Solenoid valve, 407. Evacuation pipe, 408. Fastening seat, 409. Lever, 410. Rotary disc, 411. Vacuum casting box, 412. Fixed center, 413. Gear, 414. Moving plate, 415. Drive motor, 416. Casting pipe, 417. Connecting hose, 418. Second fastening screw, 419. Drive screw, 420. Movable center, 421. Fixed plate, 422. Return spring, 423. Support seat, 424. O-ring, 500. Mandrel, 600. Nut. Detailed Implementation

[0049] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0050] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0051] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0052] Example 1

[0053] Reference Figures 1-4This embodiment provides a combined riser pipe for low-pressure aluminum alloy casting. It combines a riser inner liner 103 made of graphite, a riser outer sleeve 101, and a riser base pipe 104 made of heat-resistant steel to form a riser pipe 100. Graphite has excellent high-temperature and corrosion resistance, as well as good lubricity and chemical stability, and outstanding resistance to thermal erosion. In operation, the aluminum alloy casting liquid flows in a laminar and horizontal state in the riser pipe 100. The good lubricity and chemical stability of the graphite pipe wall result in low resistance for the riser liquid in the riser pipe 100. The riser base pipe 104 ensures sufficient mechanical strength of the riser pipe 100 as a whole, while also ensuring good airtightness. Due to the heat-resistant coating sprayed on its surface, its heat resistance is also guaranteed.

[0054] A combined riser pipe for low-pressure casting of aluminum alloy includes a riser inner liner 103, a riser base pipe 104 fixedly connected to the outer periphery of the riser inner liner 103, and a riser outer sleeve 101 fixedly connected to the outer periphery of the riser base pipe 104. The riser inner liner 103 and the riser outer sleeve 101 are both made of graphite, and the riser base pipe 104 is made of heat-resistant steel.

[0055] Specifically, a connecting step 104c is fixed to the upper end of the riser base pipe 104, and an installation step 104b is fixed to the outer periphery of the riser base pipe 104 below the connecting step 104c. A plurality of first base pipe pin holes 104d are arranged on the riser base pipe 104 between the connecting step 104c and the installation step 104b. A plurality of first inner liner pipe pin holes 103b, corresponding one-to-one with the first base pipe pin holes 104d, is fixed to the riser base pipe 104 below the installation step 104b, and a plurality of second base pipe pin holes 104e are arranged on the riser base pipe 104 below the adaptation step 104a. A plurality of second base pipe pin holes 104e, one-to-one with the second base pipe pin holes 104e, are arranged on the riser outer sleeve pipe 101. The corresponding sleeve pin hole 101b, the riser inner liner tube 103 has several second inner liner tube pin holes 103a that correspond one-to-one with the second base tube pin hole 104e, the first base tube pin hole 104d and the corresponding first inner liner tube pin hole 103b form a first connecting hole, the sleeve pin hole 101b, the corresponding second base tube pin hole 104e and the corresponding second inner liner tube pin hole 103a form a second connecting hole, the first connecting hole is provided with a first phase change plug 102, the second connecting hole is provided with a second phase change plug 105, the riser base tube 104 is connected to the riser inner liner tube 103 through the first phase change plug 102, and the riser outer sleeve tube 101, the riser base tube 104 and the riser inner liner tube 103 are connected together through several second phase change plugs 105.

[0056] An annular first sealing groove 104b-2 is provided on the downward side of the mounting step 104b, and an annular second sealing groove 104a-1 is provided on the outer periphery of the fitting step 104a. The opening of the first sealing groove 104b-2 has a 45° chamfer. The outer diameter of the fitting step 104a is 0.1 mm smaller than the inner diameter of the corresponding mounting hole on the cover plate 202 of the heat preservation furnace 200.

[0057] The method of using riser tube 100 includes the following steps:

[0058] An asbestos rope sealing strip 106, made of woven asbestos rope, is installed in the second sealing groove 104a-1. The asbestos rope sealing strip 106 serves as the first seal, and its high temperature resistance effectively creates a sealing effect.

[0059] In the first sealing groove 104b-2, a metal sealing strip 107 made of copper is installed. The metal sealing strip 107 is about 0.2mm higher than the lower surface of the installation step 104b. The copper metal sealing strip 107 serves as the second seal. Since the melting point of copper is greater than that of aluminum alloy, it can effectively supplement the first seal and effectively ensure the sealing between the combined riser pipe 100 and the cover plate 202 of the heat preservation furnace 200.

[0060] The riser pipe 100 is installed into the mounting hole on the cover plate 202 at the upper end of the insulation furnace 200. The bolt holes 104b-1 arranged in a circular array on the mounting step 104b of the cover plate 202 and the threaded holes on the cover plate 202 are used to fasten the two with the first fastening screw 300. When fastening, the metal sealing strip 107, which is 0.2mm higher than the large surface below the mounting step 104b of the cover plate 202, is squeezed into the 45° chamfer of the first sealing groove 104b-2, which effectively solves the airtightness requirement of the installation of this combined riser pipe 100.

[0061] The steps for using the riser 100 are as follows: pour the molten aluminum alloy casting liquid into the crucible 201 in the holding furnace 200 (e.g., Figure 5The cover plate 202 of the holding furnace 200 is installed on the upper port of the holding furnace 200. Using fastening screws, the combined riser pipe 100, equipped with an asbestos rope sealing strip 106 and a metal sealing strip 107, is installed into the mounting hole on the cover plate 202 of the holding furnace 200. At this time, a sealed space is formed inside the holding furnace 200. The lower part of the combined riser pipe 100 is immersed in the molten aluminum alloy casting liquid, but the height of the aluminum alloy casting liquid does not exceed the riser outer sleeve of the combined riser pipe 100. At a height of 101, the casting port connecting step 104c above the combined riser pipe 100 is connected to the casting port below the low-pressure casting mold using external equipment. The external high-pressure air, after being dried, enters the holding furnace 200 through the compressed air inlet pipe 403203. Driven by the high-pressure air, the aluminum alloy casting liquid enters the inner liner pipe in a laminar flow and flat pushing state through the tapered hole 101a below the combined riser pipe 100, and then enters the mold cavity of the low-pressure casting mold in an anti-gravity state.

[0062] Example 2

[0063] Reference Figures 5-10 This embodiment is based on Embodiment 1, but differs from Embodiment 1 in that it provides a method for preparing a riser tube for low-pressure casting of aluminum alloy, which can further realize a reliable connection between the riser base tube 104, the riser inner liner tube 103 and the riser outer sleeve tube 101.

[0064] This invention provides a method for preparing a combined riser pipe for low-pressure casting of aluminum alloys, comprising the following steps:

[0065] 1. Machining the riser base pipe 104;

[0066] 2. Machining the liquid riser liner 103;

[0067] 3. Machining the liquid riser outer casing 101;

[0068] 4. Assemble the inner lifting liner 103, the base lifting pipe 104, and the outer lifting pipe 101 together and fix them in place.

[0069] The specific processing steps in step 1 are as follows:

[0070] 101. Heat-resistant steel bars are used, and each surface is rough-machined using a lathe with a 1mm allowance.

[0071] 102. Use a drilling machine and indexing equipment to process the bolt holes 104b-1 arranged in a circular array on the mounting table, and the first base pipe pin hole 104d and the second base pipe pin hole 104e arranged in a circular array on the riser base pipe 104.

[0072] 103. Aging to relieve processing stress;

[0073] 104. When semi-finishing on each surface using a lathe, leave a 0.5mm allowance;

[0074] 105. Quenching treatment;

[0075] 106. Use a turning machine with ceramic cutting tools to finish all surfaces to the required dimensions;

[0076] 107. Surface sandblasting treatment, followed by thorough cleaning and drying;

[0077] 108. Apply heat-resistant coating to the surface using a wet method and then dry.

[0078] The specific processing steps in step 2 are as follows:

[0079] 201. Graphite tube material is used, and the outer diameter of the inner hole is bored using a lathe to ensure that the outer diameter of the riser liner 103 is 0.02-0.04 mm smaller than the inner diameter of the riser base tube 104, and that the total length of the riser liner 103 is equal to that of the riser base tube 104.

[0080] 2-2. Using a drilling machine and indexing equipment, machine the liner pin holes on the outer periphery of the riser inner liner 103. The position and number of these holes are consistent with the first base pipe pin hole 104d and the second base pipe pin hole 104e on the riser base pipe 104.

[0081] The specific processing steps in step 3 are as follows:

[0082] 301. Graphite tube material is used, and the outer diameter of the inner hole is bored using a turning machine tool to ensure that the outer diameter of the lifting outer tube 101 is smaller than the outer diameter of the matching step 104a, so as to facilitate the installation of the combined lifting tube 100. The taper of the tapered hole 101a below the lifting outer tube 101 is 45°, and the bottom diameter of the tapered hole 101a is equal to the inner diameter of the lifting inner liner tube 103.

[0083] 302. Using a drilling machine and indexing equipment, machine the sleeve pin holes 101b on the outer periphery of the lifting outer sleeve 101, the number and location of which are consistent with the second base pipe pin holes 104e.

[0084] In step 4, the specific assembly process is as follows:

[0085] 401. Install the inner liner tube 103 into the inner hole of the base tube 104, making them aligned in the length direction. Gently rotate the inner liner tube 103 so that the pin hole of the inner liner tube on its outer surface is approximately coaxial with the first pin hole and the second pin hole of the base tube on the base tube 104.

[0086] 402. Insert the lifting outer sleeve 101 into the lower end of the lifting base tube 104 until the lifting base tube 104 contacts the bottom surface of the inner hole of the lifting outer sleeve 101. Gently rotate the lifting outer sleeve 101 so that the sleeve pin hole 101b on its outer surface is approximately coaxial with the second base tube pin hole 104e.

[0087] 403. Molten brass is poured into the combined pin holes consisting of the pin holes on the riser outer tube 101, the riser base tube 104, and the riser inner liner tube 103. After the brass cools and solidifies, a first phase change pin and a second phase change pin are formed. The first phase change pin is locked to the riser base tube 104 and the riser inner liner tube 103, and the second phase change pin is locked to the riser outer tube 101, the riser base tube 104, and the riser inner liner tube 103. When the brass is poured, it also flows into the gaps in the assembly of the riser outer tube 101, the riser base tube 104, and the riser inner liner tube 103. After cooling, a thin layer of brass is formed.

[0088] 404. Grind the exposed parts of the first and second phase change pins after casting so that they are flush with the outer surface of the ring. Clean up dust and debris, spray a heat-resistant coating on the outer step end face of the first phase change pin, and then dry it.

[0089] In step 403, a vacuum casting device 400 is used to cast the liquid-lifting base pipe 104, the liquid-lifting outer sleeve pipe 101, and the liquid-lifting inner liner pipe 103 together. The vacuum casting device 400 includes a vacuum casting chamber 411. The upper end of the vacuum casting chamber 411 is connected to a vacuum gauge 405, a solenoid valve 406 for maintaining pressure or releasing vacuum, and a vacuum extraction pipe 407. The vacuum extraction pipe 407 is connected to an external vacuum pump. The front end of the vacuum casting chamber 411 is connected to an openable door 402. A fixed top 412 is fixedly connected to one end of the vacuum casting chamber 411 in the left-right direction, and a guide seat is fixedly connected to the other end of the vacuum casting chamber 411 in the left-right direction. A movable top 420 is slidably connected to the guide seat, and the movable top 420 is away from the fixed top. Several reset elastic elements are arranged at one end of the tip 412. A fixed plate 421 is fixedly connected to the right side of the vacuum casting box 411. The end of the reset elastic element away from the movable tip 420 is connected to the fixed plate 421. A mandrel 500 is rotatably connected between the fixed tip 412 and the movable tip 420. A rotating disk 410 is rotatably connected to the fixed tip 412. A support base 423 is fixedly connected to the side wall of the vacuum casting box 411. A center hole is opened in the center of the support base 423. A rocker arm is rotatably connected to the support base 423 through the center hole. Several four-and-a-half "O" rings are provided on the inner wall of the center hole of the support base 423. The rocker arm also has four and a half "O" rings. The spacing between the two half "O" rings is consistent. An O-ring is installed in the "" type sealing ring to seal the rocker arm seat and rocker arm, and also to prevent the rocker arm from moving within the support base 423. One end of the rocker arm is outside the vacuum casting chamber 411, and the other end extends into the vacuum casting chamber 411 and is connected to a gear 413 that mates with the rotating disk 410. A lever 409 is fixedly connected to the right end of the rotating disk 410. The end of the mandrel 500 away from the connecting step 104c has a round hole that mates with the lever 409. The combined lifting tube fits onto the mandrel 500 through the lifting inner liner tube. One end of the mandrel 500 in the left-right direction rests on the fixed center 412, and the outer circumference of the other end of the mandrel 500 in the left-right direction has external threads. A nut 600 is threadedly connected to the mandrel 500 through the external threads. The mother tube 600 presses the liquid-lifting base tube 104 and the liquid-lifting inner liner tube 103 onto the liquid-lifting outer sleeve tube 101 at the upper end of the tapered hole 101a. A transmission screw 419 is rotatably connected inside the vacuum casting box 411 above the combined liquid-lifting tube 100. A transmission motor 415 is fixedly connected to the left side of the vacuum casting box 411. The transmission motor 415 is connected to the transmission screw 419. A movable plate 414 is threadedly connected to the transmission screw 419 and slidably connected inside the vacuum casting box 411. A fastening seat 408 is fixedly connected to the movable plate 414. A casting pipe 416 is fixedly connected to the fastening seat 408 via a second fastening screw 418. An upper adapter 404 is fixedly connected to the upper end of the vacuum casting box 411, and a lower adapter is connected to the upper end of the casting pipe 416.A connecting hose 417 is fixedly connected between the upper adapter 404 and the lower adapter.

[0090] When using a vacuum casting machine (400) to cast phase change anti-locking agents, the following steps are included:

[0091] Install the assembled combined riser tube 100 onto the mandrel 500, and tighten the combined riser tube 100 using the nut 600. Open the door 402 using the handle, insert the center hole at one end of the mandrel 500 into the movable center 420, and push the movable center 420 to the right to press the return spring 422, allowing the center hole at the other end of the mandrel 500 to be inserted into the fixed center 412. At the same time, insert the lever 409 on the rotating disk 410 into the round hole on the left side of the mandrel 500, releasing the pressure of the movable center 420 on the return spring 422. Under the action of the return spring 422... The fixed tip 412 and movable tip 420 are used to press the mandrel 500 together. The second fastening screw 418 is used to adjust the pouring pipe 416 to the ideal pouring height and lock it. The door 402 is closed using the handle, the solenoid valve 406 is closed, and the external vacuum pump is turned on. A vacuum is drawn into the vacuum pouring equipment 400 through the suction pipe 407. When the vacuum gauge 405 detects that the vacuum level inside the vacuum pouring equipment 400 meets the operational requirements, the vacuum pump is turned off. If the vacuum level is lower than the operational requirements, the vacuum pump is turned on. The combined type can be clearly seen through the viewing window 401 (located on the door 402). The position of the pin hole on the riser pipe 100 is adjusted by manually rotating the disc-shaped handle on the outside of the rocker arm to make the pin hole perpendicular to the casting pipe 416. This controls the start of the drive motor 415, which drives the casting pipe 416 above the pin hole to be cast via the drive screw 419. The controller opens or closes the external supply of casting liquid, allowing the molten brass to flow through the upper adapter 404, connecting hose 417, lower adapter, and casting pipe 416, pouring the molten brass into the pin hole. After the brass cools and solidifies, the first... The phase change pin or the second phase change pin is controlled by opening and closing the drive motor 415, which drives the moving plate 414 to move the pouring pipe 416 to achieve multi-point pouring. When all the pin holes on the same vertical plane are poured, the rocker arm is rotated to make the unpoured pin holes perpendicular to the pouring pipe 416. Repeating the above pouring steps will pour all the pin holes. The exposed parts of the first and second phase change pins after casting are ground to make them flush with the outer circumference. Dust and debris are cleaned, and a heat-resistant coating is sprayed on the outer step end face of the first phase change pin, followed by drying.

[0092] Because it is vacuum casting, the pins are well formed. After cooling, a thin layer of brass is formed in the gaps between the components, which effectively supports the inner liner 103 and the outer liner 101 assembled on the riser base tube 104. This results in excellent bonding between the riser base tube 104 and the inner liner 103 and the outer liner 101, greatly improving the thermal shock resistance of the combined riser tube 100 and extending its service life. After casting is completed, the vacuum is released by opening the solenoid valve 406 through the controller, the door 402 is opened, the mandrel 500 is taken out, the nut 600 is loosened, and the combined riser tube 100 is removed.

[0093] When the combined riser tube 100 needs to be disassembled for maintenance, the combined riser tube 100 is placed in the furnace and heated until the melting point of brass is reached. After the first phase change pin and the second phase change pin are completely liquefied, the molten brass liquid is poured out, and the combined riser tube 100 can be disassembled.

[0094] The vacuum casting equipment 400 in this embodiment effectively solves the problems of air bubbles and incomplete casting in ordinary casting, and effectively eliminates the gap between the different materials of the combined riser tube 100, thereby solving the problem of poor bonding between the metal base tube and the non-metallic protective sheet of the composite material riser tube 100.

[0095] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a combined riser pipe for low-pressure casting of aluminum alloy, characterized in that: The combined riser pipe for low-pressure casting of aluminum alloy includes a riser inner liner (103), a riser base pipe (104) fixedly connected to the outer periphery of the riser inner liner (103), and a riser outer sleeve (101) fixedly connected to the outer periphery of the riser base pipe (104). Both the riser inner liner (103) and the riser outer sleeve (101) are made of graphite, and the riser base pipe (104) is made of heat-resistant steel. The upper end of the riser base pipe (104) is fixed... There is a connecting step (104c), and an installation step (104b) is fixed on the outer periphery of the riser base pipe (104) below the connecting step (104c). A plurality of first base pipe pin holes (104d) are arranged on the riser base pipe (104) between the connecting step (104c) and the installation step (104b). A plurality of first inner liner pipes corresponding one-to-one with the first base pipe pin holes (104d) are arranged on the riser inner liner pipe (103). The mounting step (104b) has a pin hole (103b). A downwardly extending adapter step (104a) is fixed on the lifting base pipe (104) below the mounting step (104b). Several second base pipe pin holes (104e) are arranged on the lifting base pipe (104) below the adapter step (104a). Several sleeve pin holes (101b) corresponding one-to-one with the second base pipe pin holes (104e) are arranged on the lifting outer sleeve (101). The liquid liner tube (103) has a plurality of second liner tube pin holes (103a) that correspond one-to-one with the second base tube pin holes (104e). The first base tube pin hole (104d) and the corresponding first liner tube pin hole (103b) form a first connecting hole. The sleeve pin hole (101b), the corresponding second base tube pin hole (104e) and the corresponding second liner tube pin hole (103a) form a second connecting hole. Includes the following steps, 1. Machining the riser base pipe (104); 2. Machining the liquid riser liner (103); 3. Machining the riser jacket (101); 4. Assemble the inner lifting liner (103), the base lifting pipe (104), and the outer lifting pipe (101) together; the specific assembly process is as follows:

401. Install the lifting liner (103) into the inner hole of the lifting base pipe (104) so ​​that the two are aligned in the length direction. Gently rotate the lifting liner (103) so that the pin hole of the liner on its outer circumference is approximately coaxial with the first pin hole and the second pin hole of the base pipe on the lifting base pipe (104).

402. Insert the lifting outer tube (101) into the lower end of the lifting base tube (104) until the lifting base tube (104) contacts the bottom surface of the inner hole of the lifting outer tube (101). Gently rotate the lifting outer tube (101) so that the sleeve pin hole (101b) on its outer circumference is approximately coaxial with the second base tube pin hole (104e).

403. Molten brass is poured into the combined pin holes consisting of the pin holes on the riser outer tube (101), riser base tube (104), and riser inner liner tube (103). After the brass cools and solidifies, a first phase change pin and a second phase change pin are formed. The first phase change pin is pinned to the riser base tube (104) and the riser inner liner tube (103), and the second phase change pin is pinned to the riser outer tube (101), riser base tube (104), and riser inner liner tube (103). When the brass is poured, it also flows into the gaps in the assembly of the riser outer tube (101), riser base tube (104), and riser inner liner tube (103). After cooling, a thin layer of brass is formed.

404. Grind the exposed parts of the first and second phase change pins after casting so that they are flush with the outer surface of the ring. Clean up dust and debris, spray a heat-resistant coating on the outer step end face of the first phase change pin, and then dry it.

2. The method for preparing a combined riser pipe for low-pressure casting of aluminum alloy as described in claim 1, characterized in that: A first phase change pin (102) is provided at the first connection hole, and a second phase change pin (105) is provided at the second connection hole. The liquid riser base pipe (104) is connected to the liquid riser liner pipe (103) via the first phase change pin (102). The liquid riser outer sleeve pipe (101), the liquid riser base pipe (104), and the liquid riser liner pipe (103) are connected together via several second phase change pins (105).

3. The method for preparing a combined riser pipe for low-pressure casting of aluminum alloy as described in claim 2, characterized in that: The specific processing steps in step 1 are as follows:

101. Heat-resistant steel bars are used, and each surface is rough-machined using a lathe with a 1mm allowance.

102. Use a drilling machine and indexing equipment to process the bolt holes (104b-1) arranged in a circular array on the mounting table, as well as the first base pipe pin hole (104d) and the second base pipe pin hole (104e) arranged in a circular array on the riser base pipe (104).

103. Aging to relieve processing stress; 104. When semi-finishing on each surface using a lathe, leave a 0.5mm allowance; 105. Quenching treatment; 106. Use a turning machine with ceramic cutting tools to finish all surfaces to the required dimensions; 107. Surface sandblasting treatment, followed by thorough cleaning and drying; 108. Apply heat-resistant coating to the surface using a wet method and then dry.

4. The method for preparing a combined riser pipe for low-pressure casting of aluminum alloy as described in claim 1, characterized in that: The specific processing steps in step 2 are as follows:

201. Using graphite tube material, the outer diameter of the inner hole is bored by turning the outer diameter of the tube on a lathe to ensure that the outer diameter of the riser liner (103) is 0.02-0.04 mm smaller than the inner diameter of the riser base tube (104), and that the total length of the riser liner (103) is equal to that of the riser base tube (104).

202. Using a drilling machine and indexing equipment, machine the second inner liner pin hole (103a) and the first inner liner pin hole (103b) on the outer periphery of the riser inner liner (103), the position and number of which are consistent with the first base pipe pin hole (104d) and the second base pipe pin hole (104e) on the riser base pipe (104).

5. The method for preparing a combined riser pipe for low-pressure casting of aluminum alloy as described in claim 1, characterized in that: The specific processing steps in step 3 are as follows:

301. Graphite tube material is used, and the outer diameter of the inner hole is bored by turning the outer diameter of the machine tool to ensure that the outer diameter of the liquid riser outer tube (101) is smaller than the outer diameter of the matching step (104a) so as to facilitate the installation of the combined liquid riser tube (100). The taper of the tapered hole (101a) below the liquid riser outer tube (101) is 45°, and the bottom hole diameter of the tapered hole (101a) is equal to the inner diameter of the liquid riser inner liner tube (103).

302. Using a drilling machine and indexing equipment, machine the sleeve pin holes (101b) on the outer periphery of the lifting outer sleeve (101), the number of which are consistent with the number of the second base pipe pin holes (104e).

6. The method for preparing a combined riser pipe for low-pressure casting of aluminum alloy as described in claim 1, characterized in that: In step 403, a vacuum casting device (400) is used to cast the riser base pipe (104), the riser outer sleeve pipe (101), and the riser inner liner pipe (103) together. The vacuum casting device (400) includes a vacuum casting box (411), the front end of which is connected to an openable door (402). A fixed center (412) is fixedly connected to one end of the vacuum casting box (411) in the left-right direction. The empty casting box (411) has a movable tip (420) that can move in the left and right direction connected to the other end. A mandrel (500) is rotatably connected between the fixed tip (412) and the movable tip (420). The combined riser pipe (100) is fitted onto the mandrel (500) through the riser liner pipe (103). One end of the mandrel (500) in the left and right direction rests on the fixed tip (412). The mandrel (500) in the left and right direction rests on the fixed tip (412). The outer circumference of the other end in the direction has an external thread, and the mandrel (500) is threaded with a nut (600) via the external thread. The nut (600) presses the riser base pipe (104) and the riser inner liner pipe (103) onto the riser outer sleeve pipe (101) at the upper end of the tapered hole (101a). A transmission screw (419) is rotatably connected inside the vacuum casting box (411) above the combined riser pipe (100). The transmission screw (419) is threaded with a... A movable plate (414) is slidably connected inside the vacuum casting box (411). A fastening seat (408) is fixedly connected to the movable plate (414). A casting pipe (416) is fixedly connected to the fastening seat (408). An upper adapter (404) is fixedly connected to the upper end of the vacuum casting box (411). A lower adapter is connected to the upper end of the casting pipe (416). A connecting hose (417) is fixedly connected between the upper adapter (404) and the lower adapter.

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