Combined riser tube for low-pressure casting of aluminum alloy and manufacturing and using method of combined riser tube

Abstract

The invention discloses a combined riser tube for aluminum alloy low-pressure casting. The combined riser tube comprises a riser liner tube, a riser base tube is fixedly connected to the periphery of the riser liner tube, a riser outer sleeve is fixedly connected to the periphery of the riser base tube, the riser base tube and the riser outer sleeve are both made of graphite, and the riser liner tube is made of heat-resistant steel; according to the combined riser tube, all parts of the combined riser tube are connected, gaps of combination between different materials of the combined riser tube are effectively eliminated, and the problem that a metal base tube and a non-metal protection piece of a composite riser tube are not well combined is solved.

Description

Technical Field

[0001] The invention relates to the technical field of casting, in particular to a combined liquid riser for low-pressure casting of aluminum alloy and a manufacturing and using method thereof. Background Art

[0002] Low-pressure casting is a casting method between gravity casting and pressure casting. Low-pressure casting has stable mold filling and crystallization and solidification under pressure holding state, which greatly improves the quality of castings. It is especially suitable for casting complex aluminum alloy parts. The riser tube is one of the key components in low-pressure casting, and its main function is to guide and compensate for shrinkage. The riser tubes currently used mainly include metal riser tubes and ceramic riser tubes. Metal riser tubes have good mechanical properties and good air tightness, but they are easy to deform at high temperatures and the coating is easy to fall off, so their service life is short. Ceramic riser tubes are resistant to high temperature and corrosion, but their mechanical properties are poor and easy to break, making them difficult to manufacture and costly. At present, there are also studies on composite material riser tubes, which use metal tubes as skeletons and inlay non-metallic guards inside and outside to achieve the purpose of protecting the metal skeleton from the erosion of high-temperature casting liquid. This type of composite riser tube usually has poor combination of metal skeleton and non-metallic guard, poor thermal shock resistance and easy damage. Therefore, in order to give full play to the advantages of composite material riser tubes in terms of material combination, it is extremely important to study the bonding strength between the metal base tube and the non-metallic guard of the composite material riser tube. Summary of the invention

[0003] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

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

[0005] Therefore, the purpose of the present invention is to provide a combined riser tube for low-pressure casting of aluminum alloys. The present invention realizes the connection between the various components of the combined riser tube, effectively eliminates the gap between different materials of the combined riser tube, and solves the problem of poor bonding between the metal base tube and the non-metallic guard plate of the composite material riser tube.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a combined riser tube for low-pressure casting of aluminum alloy, which includes a riser inner lining tube, a riser base tube is fixedly connected to the outer periphery of the riser inner lining tube, and a riser outer sleeve is fixedly connected to the outer periphery of the riser base tube, the riser inner lining tube and the riser outer sleeve are both made of graphite, and the riser base tube is made of heat-resistant steel.

[0007] As a preferred solution of the combined riser tube for low-pressure casting of aluminum alloy in the present invention, a connecting step is fixed to the upper end of the riser base tube, and an installation step is fixed to the outer periphery of the riser base tube below the connecting step.

[0008] As a preferred scheme of the combined riser tube for low-pressure casting of aluminum alloy in the present invention, wherein: a plurality of first base tube pin holes are arranged on the riser base tube between the connecting step and the installing step, a plurality of first inner liner tube pin holes corresponding to the first base tube pin holes are arranged on the riser inner liner tube, an adapting step extending downward is fixed on the riser base tube at the lower side of the installing step, a plurality of second base tube pin holes are arranged on the riser base tube below the adapting step, a plurality of casing pin holes corresponding to the second base tube pin holes are arranged on the riser outer casing, a plurality of second inner liner tube pin holes corresponding to the second base tube pin holes are arranged on the riser inner liner tube, the first base tube pin hole and the corresponding first inner liner tube pin hole form a first connecting hole, and the casing pin hole, the corresponding second base tube pin hole and the corresponding second inner liner tube pin hole form a second connecting hole.

[0009] As a preferred solution of the combined riser tube for low-pressure casting of aluminum alloy in the present invention, a first phase change stopper is provided at the first connecting hole, a second phase change stopper is provided at the second connecting hole, the riser base tube is connected to the riser inner lining tube via the first phase change stopper, and the riser outer sleeve, the riser base tube and the riser inner lining tube are connected together via a plurality of second phase change stoppers.

[0010] As another object of the present invention, the present invention provides a method for preparing a combined riser tube for low-pressure casting of aluminum alloy, comprising the following steps: 1. Processing of liquid-lifting base pipe; 2. Processing the liquid-lifting lining pipe; 3. Processing the outer casing of the liquid riser; 4. Assemble the riser inner lining tube, the riser base tube and the riser outer casing together.

[0011] As a preferred embodiment of the preparation method of the present invention, the specific processing process of step 1 is as follows: 101. Use heat-resistant steel bars and use turning machines to rough turn each surface and reserve a 1mm margin; 102. Use a drilling machine tool in combination with an indexing device to process bolt holes arranged in a circumferential array on the mounting platform, and first base pipe pin holes and second base pipe pin holes arranged in a circumferential array on the riser base pipe; 103. Aging to remove processing stress; 104. When using a turning machine to semi-finish, reserve a 0.5mm margin on each surface; 105. Quenching treatment; 106. Use a turning machine to use ceramic tools to finish each surface to the required size; 107. The surface is sandblasted, then fully cleaned and dried; 108. Spray heat-resistant coating on the wet surface and dry it.

[0012] As another object of the present invention, the present invention provides a method for preparing a combined riser tube for low-pressure casting of aluminum alloy, wherein the specific processing process of step 2 is as follows: 201. Use graphite tube material and use a turning machine to turn the outer circle and bore the inner hole to split the end surface, so as to ensure that the outer diameter of the liquid riser liner tube is 0.02-0.04mm smaller than the inner hole of the liquid riser base tube, and to ensure that the total length of the liquid riser liner tube is equal to that of the liquid riser base tube.

[0013] 2-2. Use a drilling machine tool in conjunction with a dividing device to process the liner pin holes on the outer periphery of the lift liner pipe. The positions and numbers of the liner pin holes are consistent with the first base pipe pin holes and the second base pipe pin holes on the lift base pipe.

[0014] As another object of the present invention, the present invention provides a method for preparing a combined riser tube for low-pressure casting of aluminum alloy, wherein the specific processing process of step 3 is as follows: 301. Use graphite tube material and use a turning machine to turn the outer circle and bore the inner hole to split the end face, ensuring that the outer diameter of the outer sleeve of the liquid riser is smaller than the outer diameter of the matching step to facilitate the installation of the combined liquid riser tube, ensuring that the taper of the tapered hole below the outer sleeve of the liquid riser is 45°, and the bottom hole diameter of the tapered hole is equal to the inner diameter of the liquid riser liner.

[0015] 302. Use a drilling machine tool in conjunction with a dividing device to process casing pin holes on the outer periphery of the liquid lifting outer casing, the positions and numbers of which are consistent with the pin holes of the second base pipe.

[0016] As another object of the present invention, the present invention provides a method for preparing a combined riser tube for low-pressure casting of aluminum alloy. In step 4, the specific process of assembly is as follows: 401. Install the lifting liner tube into the inner hole of the lifting base tube so that the two are flush in the length direction. Gently rotate the lifting liner tube so that the liner tube pin hole on its outer large surface is roughly coaxial with the first pin hole and the second pin hole of the base tube on the lifting base tube.

[0017] 402. Insert the liquid lifting outer sleeve into the lower end of the liquid lifting base tube until the liquid lifting base tube contacts the bottom surface of the inner hole of the liquid lifting outer sleeve, and gently rotate the liquid lifting outer sleeve so that the sleeve pin hole on the outer large surface is roughly coaxial with the pin hole of the second base tube; 403. Cast the molten brass into the combined pin holes formed by the pin holes on the riser outer sleeve, the riser base tube and the riser inner lining tube. After the brass is cooled and solidified, a first phase change pin and a second phase change pin are formed. The first phase change pin pins the riser base tube and the riser inner lining tube, and the second phase change pin pins the riser outer sleeve, the riser base tube and the riser inner lining tube. When casting, the brass also flows into the assembled gap of the riser outer sleeve, the riser base tube and the riser inner lining tube, and forms a thin layer of brass skin after cooling.

[0018] 404. Grind the exposed parts of the first phase change pin and the second phase change pin after casting to make them flush with the large outer cylindrical surface, clean up the dust and debris, spray a heat-resistant coating on the outer step end face of the first phase change pin, and then dry it.

[0019] As another object of the present invention, the present invention provides a method for preparing a combined riser tube for low-pressure casting of aluminum alloys. In step 403, a vacuum casting equipment is used to cast a riser base tube, a riser outer sleeve and a riser inner liner tube together. The vacuum casting equipment includes a vacuum casting box body, and the front end of the vacuum casting box body is connected to a door body that can be opened and closed. A fixed top is fixedly connected to one end of the vacuum casting box body in the left and right directions, and a movable top that can move in the left and right directions is connected to the other end of the vacuum casting box body in the left and right directions. A core rod is rotatably connected between the fixed top and the movable top, and the combined lifting tube is just sleeved on the core rod through the lifting inner liner tube. One end of the rod in the left and right directions is pressed against the fixed top, and the outer periphery of the other end of the core rod in the left and right directions has an external thread, and the core rod is threadedly connected to a nut through the external thread, and the nut presses the lifting base pipe and the lifting liner pipe onto the lifting outer sleeve at the upper end of the tapered hole, and a transmission screw is rotatably connected to the vacuum pouring box above the combined lifting pipe, and a movable plate slidably connected to the vacuum pouring box is threadedly connected to the transmission screw, and a fastening seat is fixedly connected to the movable plate, and a pouring pipe is fixedly connected to the fastening seat, and an upper adapter is fixedly connected to the upper end of the vacuum pouring box, and a lower adapter is connected to the upper end of the pouring pipe, and a connecting hose is fixedly connected between the upper adapter and the lower adapter.

[0020] Compared with the prior art, the present invention has the following technical effects: it realizes the connection between the various components of the combined riser pipe, effectively eliminates the gaps 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 guard sheet of the composite material riser pipe; the riser pipe formed by vacuum casting has good plug-eliminating molding, and after cooling, a thin layer of brass skin is formed in the gaps between the various components, so that the riser inner lining pipe and the riser outer sleeve assembled on the riser base pipe are effectively supported, so that the bonding force between the riser base pipe and the riser inner lining pipe and the riser outer sleeve is excellent, which greatly improves the thermal shock resistance of the combined riser pipe and greatly extends the service life of the combined riser pipe; it can be applied to low-pressure casting of aluminum alloys. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them: Figure 1 It is the internal structure diagram of the present invention.

[0022] Figure 2 This is a diagram showing the internal structure of the liquid-rising base pipe in the present invention.

[0023] Figure 3 It is a three-dimensional structural diagram of the liquid rising liner pipe in the present invention.

[0024] Figure 4 It is a three-dimensional structural diagram of the liquid lifting outer sleeve in the present invention.

[0025] Figure 5 The figure is a diagram showing the internal structure of a heat preservation furnace when the present invention is used.

[0026] Figure 6 for Figure 5 A partial enlarged view of point A in the middle.

[0027] Figure 7 for Figure 5 A partial enlarged view of point B in the middle.

[0028] Figure 8 Front view of the vacuum casting equipment used to prepare the riser tube.

[0029] Fig. 9 Diagram of the internal structure of the vacuum casting equipment used to prepare the riser tube.

[0030] Fig.10 for Fig. 9 A partial enlarged view of point C in the middle.

[0031] In the figure, 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 liner, 103a second liner pin hole, 103b first liner pin hole, 104 liters of liquid base pipe, 104a adapter step, 104a-1 second sealing groove, 104b installation 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 insulation furnace, 201 crucible crucible, 202 cover plate, 203 compressed air inlet pipe, 300 first fastening screw, 400 vacuum casting equipment, 401 window, 402 door body, 403 compressed air inlet pipe, 404 upper adapter, 405 vacuum gauge, 406 solenoid valve, 407 exhaust pipe, 408 fastening seat, 409 lever, 410 rotating disk, 411 vacuum casting box, 412 fixed top, 413 gear, 414 moving plate, 415 transmission motor, 416 casting pipe, 417 connecting hose, 418 second fastening screw, 419 transmission screw, 420 movable top, 421 fixed plate, 422 return spring, 423 support seat, 424 O-ring, 500 core rod, 600 nut. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0033] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0034] 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 term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0035] Example 1 Reference Figure 1 to Figure 4The present embodiment provides a combined riser tube for low-pressure casting of aluminum alloy, which combines a riser inner lining tube 103 made of graphite, a riser outer sleeve 101 and a riser base tube 104 made of heat-resistant steel into a riser tube 100. The graphite material has excellent high temperature resistance and corrosion resistance, as well as good lubricity and chemical stability, and its heat corrosion resistance is also very outstanding. In working conditions, the aluminum alloy casting liquid is in a laminar push state in the riser tube 100. The good lubricity and chemical stability of the graphite material tube wall have a low resistance effect on the rising liquid in the casting liquid riser tube 100; the riser base tube 104 can ensure sufficient mechanical strength of the riser tube 100 as a whole, while ensuring good airtightness. Since a heat-resistant coating is sprayed on its surface, its heat resistance is also guaranteed.

[0036] A combined riser tube for low-pressure casting of aluminum alloy comprises a riser inner liner tube 103, a riser base tube 104 is fixedly connected to the outer periphery of the riser base tube 104, a riser outer sleeve 101 is fixedly connected to the outer periphery of the riser base tube 104, the riser inner liner tube 103 and the riser outer sleeve 101 are both made of graphite, and the riser base tube 104 is made of heat-resistant steel.

[0037] Specifically, a connecting step 104c is fixed to the upper end of the liquid lifting base pipe 104, an installation step 104b is fixed to the outer periphery of the liquid lifting base pipe 104 below the connecting step 104c, a plurality of first base pipe pin holes 104d are arranged on the liquid lifting base pipe 104 between the connecting step 104c and the installation step 104b, a plurality of first inner liner pipe pin holes 103b corresponding to the first base pipe pin holes 104d are arranged on the liquid lifting inner liner pipe 103, an adapting step 104a extending downward is fixed to the liquid lifting base pipe 104 below the installation step 104b, a plurality of second base pipe pin holes 104e are arranged on the liquid lifting base pipe 104 below the adaptation step 104a, and a plurality of first and second base pipe pin holes 104e corresponding to each other are arranged on the liquid lifting outer casing 101. The corresponding casing pin hole 101b, the lifting liner pipe 103 is arranged with several second liner pipe pin holes 103a corresponding to the second base pipe pin holes 104e, the first base pipe pin hole 104d and the corresponding first liner pipe pin hole 103b form a first connecting hole, the casing pin hole 101b, the corresponding second base pipe pin hole 104e and the corresponding second liner pipe pin hole 103a form a second connecting hole, a first phase change stopcock 102 is provided at the first connecting hole, a second phase change stopcock 105 is provided at the second connecting hole, the lifting base pipe 104 is connected to the lifting liner pipe 103 via the first phase change stopcock 102, and the lifting outer casing 101, the lifting base pipe 104 and the lifting liner pipe 103 are connected together via several second phase change stopcocks 105.

[0038] A first annular sealing groove 104b-2 is opened on the downward side of the installation step 104b, and a second annular sealing groove 104a-1 is opened on the outer periphery of the adaptation step 104a. The opening of the first sealing groove 104b-2 has a 45° chamfer, and the outer diameter of the adaptation step 104a is 0.1 mm smaller than the inner diameter of the corresponding installation hole on the cover plate 202 of the insulation furnace 200.

[0039] The method of using the riser tube 100 comprises the following steps: 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 is used as the first seal and can effectively form a sealing effect due to its extreme high temperature resistance. A metal sealing strip 107 made of copper is installed in the first sealing groove 104b-2. The metal sealing strip 107 is about 0.2 mm higher than the large surface below the installation step 104b. The metal sealing strip 107 made of copper is used as the second seal. Since the melting point of copper is greater than that of aluminum alloy, it can be used as an effective supplement to the first seal, effectively ensuring the sealing problem between the combined liquid riser 100 and the cover plate 202 of the insulation furnace 200. The riser pipe 100 is installed into the mounting hole on the cover plate 202 at the upper end of the insulation furnace 200, and 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 using the first fastening screws 300. When fastening, the metal sealing strip 107, which is 0.2 mm 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, thereby effectively solving the airtightness requirement of the installation of the combined riser pipe 100.

[0040] The step of using the riser tube 100 is to pour the molten aluminum alloy casting liquid into the crucible 201 (such as Figure 5 ), install the cover plate 202 of the insulation furnace 200 on the upper port of the insulation furnace 200, and use the fastening screws to install the combined liquid riser 100 equipped with the asbestos rope sealing strip 106 and the metal sealing strip 107 into the installation hole on the cover plate 202 of the insulation furnace 200. At this time, a closed space is formed in the insulation furnace 200, and the lower part of the combined liquid riser 100 is immersed in the molten aluminum alloy casting liquid, but the height of the aluminum alloy casting liquid does not exceed the outer casing of the combined liquid riser 100. 101, the casting port connecting step 104c surface above the combined riser pipe 100 is connected to the casting port below the low-pressure casting mold by peripheral equipment, and the dried external high-pressure air enters the insulation furnace 200 through the compressed air inlet pipe 403203. Driven by the high-pressure air, the aluminum alloy casting liquid enters the inner lining pipe in a laminar push state through the tapered hole 101a below the combined riser pipe 100, and then enters the low-pressure casting mold cavity in an anti-gravity state.

[0041] Example 2 Reference Figures 5 to 10 This embodiment is based on Example 1, and the difference from Example 1 is that this embodiment 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 lining tube 103 and the riser outer casing 101.

[0042] The present invention provides a method for preparing a combined riser tube for low-pressure casting of aluminum alloy, comprising the following steps: 1. Processing the liquid-lifting base pipe 104; 2. Processing the liquid-lifting liner pipe 103; 3. Processing the liquid lifting outer sleeve 101; 4. Assemble the liquid riser lining tube 103, the liquid riser base tube 104 and the liquid riser outer casing 101 together and fix them.

[0043] The specific processing process of step 1 is: 101. Use heat-resistant steel bars and use turning machines to rough turn each surface and reserve a 1mm margin; 102. Use a drilling machine tool in combination with an indexing device to process the bolt holes 104b-1 arranged in a circumferential array on the mounting table, and the first base pipe pin holes 104d and the second base pipe pin holes 104e arranged in a circumferential array on the riser base pipe 104; 103. Aging to remove processing stress; 104. When using a turning machine to semi-finish, reserve a 0.5mm margin on each surface; 105. Quenching treatment; 106. Use a turning machine to use ceramic tools to finish each surface to the required size; 107. The surface is sandblasted, then fully cleaned and dried; 108. Spray heat-resistant coating on the wet surface and dry it.

[0044] The specific processing process of step 2 is: 201. Use graphite tube material and use a turning machine to turn the outer circle and bore the inner hole to split the end surface, ensuring that the outer diameter of the liquid riser liner tube 103 is 0.02-0.04mm smaller than the inner hole of the liquid riser base tube 104, and ensuring that the total length of the liquid riser liner tube 103 is equal to that of the liquid riser base tube 104.

[0045] 2-2. Use a drilling machine in conjunction with a dividing device to machine the liner pin holes on the outer periphery of the lift liner 103 , the positions and numbers of which are consistent with the first base pipe pin holes 104 d and the second base pipe pin holes 104 e on the lift base pipe 104 .

[0046] The specific processing process of step 3 is: 301. Use graphite tube material and use a turning machine to turn the outer circle and bore the inner hole to split the end surface, ensure that the outer diameter of the liquid lifting outer sleeve 101 is smaller than the outer diameter of the adaptation step 104a, so as to facilitate the installation of the combined liquid lifting tube 100, and ensure that the taper of the tapered hole 101a below the liquid lifting outer sleeve 101 is 45°, and the bottom hole diameter of the tapered hole 101a is equal to the inner diameter of the liquid lifting inner liner 103.

[0047] 302. Use a drilling machine tool in conjunction with an indexing device to process the casing pin holes 101b on the outer periphery of the liquid lifting outer casing 101, the positions and numbers of which are consistent with the second base pipe pin holes 104e.

[0048] In step 4, the specific process of assembly is: 401. Install the lifting liner tube 103 into the inner hole of the lifting base tube 104 so that the two are flush in the length direction. Gently rotate the lifting liner tube 103 so that the liner tube pin hole on its outer large surface is roughly coaxial with the first pin hole and the second pin hole of the base tube on the lifting base tube 104.

[0049] 402. Insert the liquid lifting outer sleeve 101 into the lower end of the liquid lifting base tube 104 until the liquid lifting base tube 104 contacts the bottom surface of the inner hole of the liquid lifting outer sleeve 101, and gently rotate the liquid lifting outer sleeve 101 so that the sleeve pin hole 101b on the outer large surface is roughly coaxial with the second base tube pin hole 104e; 403. Cast the molten brass liquid into the combined pin holes formed by the pin holes on the riser outer sleeve 101, the riser base tube 104 and the riser inner liner tube 103. After the brass liquid is cooled and solidified, a first phase change pin and a second phase change pin are formed, wherein the first phase change pin pins the riser base tube 104 and the riser inner liner tube 103, and the second phase change pin pins the riser outer sleeve 101, the riser base tube 104 and the riser inner liner tube 103. When casting, the brass liquid also flows into the assembled gap of the riser outer sleeve 101, the riser base tube 104 and the riser inner liner tube 103, and forms a thin layer of brass skin after cooling; 404. Grind the exposed parts of the first phase change pin and the second phase change pin after casting to make them flush with the large outer cylindrical surface, clean up the dust and debris, spray a heat-resistant coating on the outer step end face of the first phase change pin, and then dry it.

[0050] In step 403, a vacuum casting device 400 is used to cast the liquid riser base pipe 104, the liquid riser outer sleeve 101 and the liquid riser inner liner pipe 103 together. The vacuum casting device 400 includes a vacuum casting box 411. The upper end of the vacuum casting box 411 is connected to a vacuum gauge 405, a solenoid valve 406 for maintaining pressure or releasing vacuum, and an exhaust pipe 407. The exhaust pipe 407 is connected to an external vacuum pump. The front end of the vacuum casting box 411 is connected to a door body 402 that can be opened and closed. A fixed top 412 is fixedly connected to one end of the vacuum casting box 411 in the left and right directions. A guide seat is fixedly connected to the other end of the vacuum casting box 411 in the left and right directions. A movable top 420 is slidably connected to the guide seat. The movable top 420 is away from the fixed top. A plurality of resetting elastic members 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, an end of the resetting elastic member away from the movable top 420 is connected to the fixed plate 421, a core rod 500 is rotatably connected between the fixed top 412 and the movable top 420, a rotating disk 410 is rotatably connected to the fixed top 412, a support seat 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 seat 423, a rocker is rotatably connected to the support seat 423 through the center hole, a plurality of 4 and a half "O" type sealing rings are arranged on the inner wall of the center hole of the support seat 423, and 4 and a half "O" type sealing rings are also arranged on the rod body of the rocker, and the spacing between the two half "O" type sealing rings is consistent, and the two half "O" type sealing rings are connected at the same distance. An O-ring is installed in the "-shaped sealing ring, which can make the rocker seat and the rocker in a sealed state, and at the same time prevent the rocker from moving in the support seat 423. One end of the rocker is outside the vacuum casting box 411, and the other end of the rocker extends into the vacuum casting box 411 and is connected to a gear 413 that cooperates with the rotating disk 410. The right end of the rotating disk 410 is fixedly connected to a lever 409, and a round hole that cooperates with the lever 409 is opened at one end of the core rod 500 away from the connecting step 104c. The combined lifting pipe is just sleeved on the core rod 500 through the lifting liner pipe, and one end of the core rod 500 in the left and right direction is pressed on the fixed top 412. The outer periphery of the other end of the core rod 500 in the left and right direction has an external thread, and the core rod 500 is threadedly connected with a nut 600 through the external thread. The mother 600 presses the liquid lifting base pipe 104 and the liquid lifting inner liner pipe 103 onto the liquid lifting outer sleeve 101 at the upper end of the tapered hole 101a. A transmission screw 419 is rotatably connected in the vacuum pouring box 411 above the combined liquid lifting pipe 100. A transmission motor 415 is fixedly connected to the left side of the vacuum pouring box 411. The transmission motor 415 is connected to the transmission screw 419. A movable plate 414 slidably connected to the vacuum pouring box 411 is threadedly connected on the transmission screw 419. A fastening seat 408 is fixedly connected to the movable plate 414. The fastening seat 408 is fixedly connected to the pouring pipe 416 via a second fastening screw 418. The upper end of the vacuum pouring box 411 is fixedly connected to the upper adapter 404. The upper end of the pouring pipe 416 is connected to the lower adapter.A connecting hose 417 is fixedly connected between the upper adapter 404 and the lower adapter.

[0051] When using the vacuum casting equipment 400 to cast the phase change plug, the following steps are included: Install the assembled combined liquid riser 100 onto the mandrel 500, tighten the combined liquid riser 100 with the nut 600, open the door 402 with the handle, insert the top hole at one end of the mandrel 500 into the movable top 420, push the movable top 420 to the right to compress the return spring 422, so that the top hole at the other end of the mandrel 500 can be inserted into the fixed top 412, and at the same time, insert the lever 409 on the rotating disk 410 into the circular hole on the left side of the mandrel 500, release the pressing force of the movable top 420 on the return spring 422, and under the action of the return spring 422 , the fixed top 412 and the movable top 420 press the core rod 500, use the second fastening screw 418 to adjust the pouring tube 416 to the ideal pouring height and lock it, use the handle to close the door body 402, close the solenoid valve 406, turn on the external vacuum pump, and evacuate the inside of the vacuum pouring equipment 400 through the exhaust pipe 407. When the vacuum gauge 405 detects that the vacuum degree inside the vacuum pouring equipment 400 meets the operating requirements, the vacuum pump is controlled to be turned off. If the vacuum degree is lower than the operating requirements, the vacuum pump is turned on, and the combined type is clearly seen through the window 401 (which is set on the door body 402). The position of the pin hole on the liquid riser 100 is adjusted to a position perpendicular to the pouring tube 416 by manually rotating the disc-shaped handle on the outer side of the rocker, and the transmission motor 415 is controlled to start, and the pouring tube 416 is driven by the transmission screw 419 to be placed above the pin hole to be poured. The controller controls the opening or closing of the external pouring liquid supply device to realize the flow of molten brass liquid. The molten brass liquid is poured into the pin hole through the upper adapter 404, the connecting hose 417, the lower adapter and the pouring tube 416. After the brass liquid is cooled and solidified, a first The phase change pin or the second phase change pin drives the moving plate 414 to drive the pouring tube 416 to shift by controlling the opening and closing of the transmission motor 415 to realize multi-point pouring. When all the pin holes on the same vertical plane are poured, the rocker is rotated to make the uncast pin holes perpendicular to the pouring tube 416. Repeating the above pouring steps can pour all the pin holes; grind the exposed parts of the first phase change pin and the second phase change pin after casting to make them flush with the large outer cylindrical surface, 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.

[0052] Since it is vacuum casting, the pin is well formed, and after cooling, a thin layer of brass is formed in the gaps connecting the components, so that the lifting lining tube 103 and the lifting outer sleeve 101 assembled on the lifting base tube 104 are effectively supported, so that the bonding force between the lifting base tube 104 and the lifting lining tube 103 and the lifting outer sleeve 101 is excellent, which greatly improves the thermal shock resistance of the combined lifting tube 100 and greatly extends the service life of the combined lifting tube 100. When the casting is completed, the solenoid valve 406 is opened by the controller to release the vacuum, the door body 402 is opened, the core rod 500 is taken out, the nut 600 is loosened, and the combined lifting tube 100 is removed.

[0053] When the combined riser tube 100 needs to be disassembled for maintenance, the combined riser tube 100 is placed in a furnace and heated to the melting point of brass. When 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.

[0054] The vacuum pouring equipment 400 in this embodiment effectively solves the problems of bubbles and incomplete pouring in ordinary pouring, and effectively eliminates the gaps between different materials in the combined riser tube 100, thereby solving the problem of poor bonding between the metal base tube and the non-metallic guard plate of the composite riser tube 100.

[0055] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A combined riser tube for low-pressure casting of aluminum alloy, characterized in that: The invention comprises a liquid riser inner lining tube (103), the outer periphery of which is fixedly connected to a liquid riser base tube (104), the outer periphery of which is fixedly connected to a liquid riser outer casing (101), the liquid riser inner lining tube (103) and the liquid riser outer casing (101) are both made of graphite, and the liquid riser base tube (104) is made of heat-resistant steel.

2. The combined riser tube for low-pressure casting of aluminum alloy according to claim 1, characterized in that: A connecting step (104c) is fixed to the upper end of the liquid lifting base pipe (104), and an installation step (104b) is fixed to the outer periphery of the liquid lifting base pipe (104) below the connecting step (104c).

3. The combined riser tube for low-pressure casting of aluminum alloy according to claim 2, characterized in that: A plurality of first base pipe pin holes (104d) are arranged on the liquid lifting base pipe (104) between the connecting step (104c) and the installation step (104b); a plurality of first liner pipe pin holes (103b) corresponding to the first base pipe pin holes (104d) are arranged on the liquid lifting liner pipe (103); an adapting step (104a) extending downward is fixed on the liquid lifting base pipe (104) below the installation step (104b); a plurality of second base pipe pin holes (104e) are arranged on the liquid lifting base pipe (104) below the adapting step (104a); A plurality of casing pin holes (101b) corresponding to the second base pipe pin holes (104e) are arranged on the liquid outer casing (101); a plurality of second inner liner pipe pin holes (103a) corresponding to the second base pipe pin holes (104e) are arranged on the liquid lifting inner liner (103); the first base pipe pin holes (104d) and the corresponding first inner liner pipe pin holes (103b) form a first connecting hole; the casing pin holes (101b), the corresponding second base pipe pin holes (104e) and the corresponding second inner liner pipe pin holes (103a) form a second connecting hole.

4. The combined riser tube for low-pressure casting of aluminum alloy according to claim 3, characterized in that: A first phase-change plug (102) is provided at the first connection hole, and a second phase-change plug (105) is provided at the second connection hole. The liquid lifting base pipe (104) is connected to the liquid lifting inner lining pipe (103) via the first phase-change plug (102), and the liquid lifting outer casing (101), the liquid lifting base pipe (104) and the liquid lifting inner lining pipe (103) are connected together via a plurality of second phase-change plugs (105).

5. A method for preparing a combined riser tube for low-pressure casting of aluminum alloy as claimed in claim 4, characterized in that: The following steps are included:

1. Processing the liquid-lifting base pipe (104); 2. Processing the liquid-lifting lining pipe (103); 3. Processing the liquid raising outer sleeve (101); 4. Assemble the liquid riser inner lining tube (103), the liquid riser base tube (104) and the liquid riser outer casing (101) together.

6. The method for preparing a combined riser tube for low-pressure casting of aluminum alloy according to claim 5, characterized in that: The specific processing process of step 1 is:

101. Use heat-resistant steel bars and use turning machines to rough turn each surface and reserve a 1mm margin; 102. Use a drilling machine tool in combination with a dividing device to process the bolt holes (104b-1) arranged in a circumferential array on the mounting platform, and the first base pipe pin holes (104d) and the second base pipe pin holes (104e) arranged in a circumferential array on the riser base pipe (104); 103. Aging to remove processing stress; 104. When using a turning machine to semi-finish, reserve a 0.5mm margin on each surface; 105. Quenching treatment; 106. Use a turning machine to use ceramic tools to finish each surface to the required size; 107. The surface is sandblasted, then fully cleaned and dried; 108. Spray heat-resistant coating on the wet surface and dry it.

7. The method for preparing a combined riser tube for low-pressure casting of aluminum alloy according to claim 5, characterized in that: The specific processing process of step 2 is:

201. Using graphite tube material, using a turning machine to turn the outer circle and bore the inner hole, ensuring that the outer diameter of the liquid riser liner tube (103) is 0.02-0.04 mm smaller than the inner hole of the liquid riser base tube (104), and ensuring that the total length of the liquid riser liner tube (103) is equal to that of the liquid riser base tube (104); 2-2. Use a drilling machine tool in conjunction with a dividing device to process the liner pin holes on the outer periphery of the lift liner (103). The positions and numbers of the liner pin holes are consistent with the first base pipe pin holes (104d) and the second base pipe pin holes (104e) on the lift base pipe (104).

8. The method for preparing a combined riser tube for low-pressure casting of aluminum alloy according to claim 5, characterized in that: The specific processing process of step 3 is:

301. Graphite tube material is used, and the end surface of the inner hole is cut by turning the outer circle using a turning machine tool to ensure that the outer diameter of the liquid lifting outer sleeve (101) is smaller than the outer diameter of the matching step (104a) to facilitate the installation of the combined liquid lifting tube (100), and the taper of the tapered hole (101a) below the liquid lifting outer sleeve (101) is 45°, and the bottom hole diameter of the tapered hole (101a) is equal to the inner diameter of the liquid lifting inner liner (103). 9.

302. Use a drilling machine tool in conjunction with a dividing device to machine the casing pin holes (101b) on the outer periphery of the liquid lifting outer casing (101), the positions and numbers of which are consistent with the second base pipe pin holes (104e).

10. The method for preparing a combined riser tube for low-pressure casting of aluminum alloy according to claim 5, characterized in that: In step 4, the specific process of assembly is:

401. Install the liquid lifting liner tube (103) into the inner hole of the liquid lifting base tube (104) so ​​that the two are flush in the length direction, and gently rotate the liquid lifting liner tube (103) so that the inner liner tube pin hole on its outer large surface is roughly coaxial with the base tube first pin hole and the base tube second pin hole on the liquid lifting base tube (104); 402. Insert the liquid lifting outer sleeve (101) into the lower end of the liquid lifting base tube (104) until the liquid lifting base tube (104) contacts the bottom surface of the inner hole of the liquid lifting outer sleeve (101), and gently rotate the liquid lifting outer sleeve (101) so that the sleeve pin hole (101b) on its outer large surface is roughly coaxial with the second base tube pin hole (104e); 403. Casting molten brass liquid into a combination of pin holes formed by pin holes on the liquid riser outer sleeve (101), the liquid riser base tube (104) and the liquid riser inner liner tube (103). After the brass liquid is cooled and solidified, a first phase change pin and a second phase change pin are formed, wherein the first phase change pin pins the liquid riser base tube (104) and the liquid riser inner liner tube (103), and the second phase change pin pins the liquid riser outer sleeve (101), the liquid riser base tube (104) and the liquid riser inner liner tube (103). When casting, the brass liquid also flows into the assembled gaps of the liquid riser outer sleeve (101), the liquid riser base tube (104) and the liquid riser inner liner tube (103), and forms a thin layer of brass skin after cooling.

404. Grind the exposed parts of the first phase change pin and the second phase change pin after casting to make them flush with the outer circumferential large surface, clean the dust and debris, spray a heat-resistant coating on the outer step end surface of the first phase change pin, and then dry it; A method for preparing a combined riser tube for low-pressure casting of aluminum alloy as described in claim 9, characterized in that: in step 403, a vacuum casting device (400) is used to cast the riser base tube (104), the riser outer sleeve (101) and the riser inner liner (103) together, the vacuum casting device (400) comprises a vacuum casting box (411), the front end of the vacuum casting box (411) is connected to a door body (402) that can be opened and closed, a fixed top (412) is fixedly connected to one end of the vacuum casting box (411) in the left and right directions, a movable top (420) that can move in the left and right directions is connected to the other end of the vacuum casting box (411) in the left and right directions, a core rod (500) is rotatably connected between the fixed top (412) and the movable top (420), and the combined riser tube is just sleeved on the core rod (500) through the riser inner liner, and one end of the core rod (500) in the left and right directions is pressed against the fixed top (412). ), the outer periphery of the other end of the mandrel (500) in the left-right direction has an external thread, the mandrel (500) is threadedly connected to a nut (600) via the external thread, the nut (600) presses the liquid riser base pipe (104) and the liquid riser inner liner pipe (103) onto the liquid riser outer sleeve (101) at the upper end of the tapered hole (101a), and a transmission screw (419) is rotatably connected in the vacuum casting box (411) above the combined liquid riser pipe (100), and the transmission screw (419) The upper thread is connected to a movable plate (414) which is slidably connected in the vacuum pouring box (411); a fastening seat (408) is fixedly connected to the movable plate (414); a pouring pipe (416) is fixedly connected to the fastening seat (408); an upper adapter (404) is fixedly connected to the upper end of the vacuum pouring box (411); a lower adapter is connected to the upper end of the pouring pipe (416); and a connecting hose (417) is fixedly connected between the upper adapter (404) and the lower adapter.

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