Open riser anti-gravity mold-filling integral solidification process device and mold-filling integral solidification method

Abstract

An open riser anti-gravity mold filling integral solidification process device comprises anti-gravity casting equipment, a casting mold, a contact, a cut-off mechanism, a guide sleeve and a plunger. The casting mold is one or a combination of a sand mold, a metal mold and a ceramic mold, the casting mold is composed of a bottom sprue layer, an upper structure layer and an internal structure, and an open riser is arranged at the top of the upper structure layer in the casting mold; and the contact is positioned in the open riser of the casting mold. The invention further claims to protect an open riser casting mold anti-gravity mold-filling integral solidification process method using the open riser anti-gravity mold-filling integral solidification process device. The open riser casting mold anti-gravity mold-filling integral solidification process method sequentially comprises the following steps: preparing a casting mold; installing equipment; performing anti-gravity mold filling; intercepting and releasing pressure; and solidifying. The method is stable in mold filling, less in slag inclusion, less in pinhole and high in feeding capacity; air holes and cold shut can be avoided, and the combustible atmosphere concentration can be effectively reduced; the universality is high, and the production efficiency, the stability and the safety are high.

Description

Technical Field

[0001] The present invention relates to the technical field of counter-gravity casting, and in particular to an open riser counter-gravity mold filling overall solidification process device and method, wherein the focus is on using a counter-gravity method to transport alloy liquid to a mold cavity until the open riser is filled, plugging the pouring gate to prevent the alloy liquid from flowing back, and adjusting the external pressure of the mold until the alloy solidifies inside the mold. Background Art

[0002] In the prior art, anti-gravity casting technology can be divided into various forms such as low-pressure casting, differential pressure casting, pressure-regulated casting and vacuum suction casting. At present, anti-gravity casting technology has been widely used in the fields of aviation, aerospace, vehicles, etc. The traditional anti-gravity casting process is to create a pressure difference between the mold cavity 21 and the internal pressure of the smelting furnace 12 to push the alloy liquid into and fill the mold cavity, and keep the alloy liquid under the external force in the anti-gravity direction until the alloy solidifies. Since the filling and solidification process is affected by external forces, the mold 21 must be a closed mold 21 as a whole, and only a dark riser design can be used inside to ensure that the alloy liquid in the mold cavity cannot rush out of the mold cavity to cause personal injury or equipment damage. However, the closed mold 21 has a poor exhaust effect, and the filling process is prone to cold shut and insufficient pouring due to the back pressure of the mold cavity.

[0003] Traditional gravity casting can use an open riser to directly pour the alloy liquid from the crucible 13 into the mold cavity along the gate. The exhaust capacity during the filling process is good, but the alloy is easily oxidized and inhaled during the pouring process due to gravity, resulting in a sharp decline in the quality of the alloy. In addition, the alloy cannot solidify under the action of external forces during solidification, and the alloy solidification temperature gradient and cooling rate inside the mold cavity cannot be adjusted, so the casting is prone to loose defects.

[0004] Therefore, people are eager to develop an open riser anti-gravity filling integral solidification process device and method to meet the complete forming, performance and quality control requirements of complex structure castings under the premise of ensuring production safety. Summary of the invention

[0005] The present invention provides an open riser anti-gravity filling integral solidification process device, the technical key of which is: it comprises an anti-gravity casting device 1, a casting mold 21, a contact 22, a cut-off mechanism 23, a guide sleeve 24, and a plunger 25; wherein: The casting mold 21 is one of the following or a combination thereof: a sand mold, a metal mold, a ceramic mold, and the casting mold 21 is composed of a bottom gate layer, an upper structure layer, and an internal structure. The bottom gate layer is the lower box, the upper structure layer is the middle box and the upper box, and the internal structure is the inner core; an open riser is arranged at the top of the upper structure layer in the casting mold 21, i.e., the upper box; The contact 22 is a sensor capable of transmitting signals, and the contact 22 is located inside the upper riser of the casting mold 21; The guide sleeve 24 has a diameter of 20-200 mm and a wall thickness of 3-20 mm in the middle, with flanges at the top and bottom, and is fixed inside the mold 21. The main body of the plunger 25 is a cylinder with a diameter of 10-180 mm, and a guide slope is processed at the bottom. The slope forms an angle of 30-85° with the central axis of the plunger body. The plunger is located inside the guide sleeve 24 as a whole. The guide sleeve and the plunger are clearance-matched, and the clearance is 0-5 mm. The number of guide sleeves 24 and plungers 25 corresponds to the number of gates in the gate layer at the bottom of the mold. The central axis of the guide sleeve 24 and the plunger 25 is perpendicular to the riser 15 and the mold installation plane, and is located on the same axis as the center line of the gate of the gate layer at the bottom of the mold. The shut-off mechanism 23 is installed above the guide sleeve 24 and connected to the plunger 25 . The shut-off mechanism 23 is used to control the ejection or retraction of the plunger 25 in the guide sleeve 24 .

[0006] The open riser anti-gravity filling integral solidification process device of the present invention preferably claims the following technical contents: The anti-gravity casting equipment 1 comprises a central control console 11, a smelting furnace 12, a crucible 13, a furnace cover 14, a riser 15, and a tank body 20; wherein: The lower part thereof is installed on the basis of the smelting furnace 12, the crucible 13 is arranged in the inner cavity of the smelting furnace 12, and the riser 15 is mostly arranged in the inner cavity of the crucible 13; the smelting furnace 12 is provided with a smelting furnace air inlet pipe 16 and a smelting furnace exhaust pipe 17; A furnace cover 14 is arranged around the upper part of the riser 15 to seal the space above the smelting furnace 12 , and a tank body 20 for sealing the upper space is arranged above the furnace cover 14 ; the tank body 20 is provided with a tank body air inlet pipe 18 and a tank body exhaust pipe 19 .

[0007] The smelting furnace air inlet pipe 16, the smelting furnace exhaust pipe 17, the tank body air inlet pipe 18, and the tank body exhaust pipe 19 are all connected to the central control console 11 for control.

[0008] The tank exhaust pipe 19 is externally connected to a vacuum pump for evacuating the tank 20 .

[0009] The open riser counter-gravity filling integral solidification process device meets the following requirements: First, the mold preparation unit meets the following requirements: The bottom gate layer of the mold 21 is designed with n gates, n≥1; the guide sleeve 24 is pre-placed inside the mold 21 and fixed, the plunger 25 is pre-placed inside the guide sleeve 24, and it is ensured that the axes of the guide column, the guide sleeve 24, and the gate coincide and are perpendicular to the bottom horizontal plane of the bottom gate layer; Second, the installation of the open riser anti-gravity filling integral solidification process device meets the following requirements: The upper end of the riser pipe 15 is connected downward to the alloy liquid in the crucible 13 in the furnace through the furnace cover 14, and the flange of the riser pipe 15 is fixed on the furnace cover 14; it is required that the center of each gate in the gate layer at the bottom of the casting mold 21 and the center of the corresponding riser pipe 15 keep a unified vertical axis; The casting mold 21 is placed on the furnace cover 14 and the riser 15 and fastened, the contact 22 on the casting mold 21 is connected to the central console 11 by wire, and the cut-off mechanism 23 is installed on the guide sleeve 24 and connected to the plunger 25; Third, the anti-gravity filling part meets the following requirements: The central control console 11 can control the opening of the air inlet pipe 16 of the smelting furnace to introduce compressed gas into the smelting furnace 12, so as to push the alloy liquid into the cavity of the casting mold 21 through the riser 15 and the pouring gate in sequence; when the alloy liquid reaches the inside of the riser in the upper structure layer, the contact 22 continuously monitors and transmits the alloy liquid level signal to the central control console 11; Fourth, the interception and pressure relief shall meet the following requirements: When the alloy liquid reaches the position of the contact 22 in the late stage of anti-gravity filling, the contact 22 sends a signal to the central control console 11, and the cut-off mechanism 23 is activated, pushing the plunger 25 to move downward rapidly in the guide sleeve 24, and the guide surface at the bottom of the plunger enters the bottom gate layer of the casting mold 21 to block the gate, and cuts off the connection between the alloy liquid in the riser 15 and the casting mold 21; then the anti-gravity casting equipment 1 controls the exhaust pipe 17 of the melting furnace to open, so that the pressure in the melting furnace 12 is relieved to normal pressure; Fifth, the open riser anti-gravity filling integral solidification process device meets the following requirements during the solidification stage: While the fourth smelting furnace 12 is relieving pressure, the plunger 25 continues to block the pouring gate and does not move. The anti-gravity casting equipment 1 opens the tank air inlet pipe 18 or the exhaust pipe 19 according to the process requirements to make the internal pressure of the tank 20 reach the set pressure. After the alloy liquid is completely solidified in the mold cavity 21, the central control console 11 sends a signal to control the shut-off mechanism 23 to pull the plunger 25 back to the inside of the guide sleeve 24; then the exhaust pipe is opened to adjust the pressure of the tank 20 to normal pressure, and then the tank 20 and the mold 21 are disassembled, and the relevant parts are cleaned for later use.

[0010] The present invention also claims protection for the open riser mold counter-gravity filling overall solidification process method of the open riser counter-gravity filling overall solidification process device, and the specific process of the method comprises the following steps and contents in sequence: Step 1, mold preparation: design n gates at the bottom gate layer of the mold 21 according to actual needs, n ≥ 1, ensure that the bottom surface of the bottom gate layer is horizontal, pre-place the guide sleeve 24 inside the mold 21 and fix it, pre-place the plunger 25 inside the guide sleeve 24, ensure that the guide column, the guide sleeve 24, and the gate axis coincide and are perpendicular to the bottom horizontal surface of the bottom gate layer; Step 2, equipment installation: After the alloy is smelted in the crucible 13, the furnace cover 14 is covered, and the riser pipe 15 is inserted into the alloy liquid in the crucible 13 in the furnace through the furnace cover 14. The flange of the riser pipe 15 is fixed to the furnace cover 14, and the center of the bottom gate of the casting mold 21 and the center of the riser pipe 15 are kept in the same vertical axis. The casting mold 21 is placed on the furnace cover 14 and the riser pipe 15 and fastened. The contact 22 on the top of the casting mold 21 is connected to the wire of the central console 11. The cut-off mechanism 23 is installed above the guide sleeve 24 and connected to the plunger 25; Step 3, anti-gravity filling: the central control console 11 controls the air inlet pipe of the smelting furnace 12 to open, and introduces compressed gas into the smelting furnace 12, pushing the alloy liquid into the mold cavity of the casting mold 21 through the riser 15 and the gate. When the alloy liquid reaches the inside of the riser in the upper structure layer, the contact 22 transmits the alloy liquid level signal to the central control console 11; Step 4, shutoff and pressure relief: When the alloy liquid reaches the set position, the central control console 11 sends a signal, the shutoff mechanism 23 is started, and the plunger 25 is pushed down quickly in the guide sleeve 24 to enter the casting mold 21 to block the gate, and after the alloy liquid in the riser 15 is cut off from connecting with the casting mold 21, the counter-gravity casting equipment 1 controls the exhaust pipe 17 of the smelting furnace to open, and the pressure in the smelting furnace 12 is relieved to normal pressure; Step 5, solidification: while the smelting furnace 12 is depressurized, the plunger 25 continues to block the pouring gate and does not move. The counter-gravity casting equipment 1 opens the tank air inlet pipe 18 or the exhaust pipe 19 according to the process requirements to make the internal pressure of the tank 20 reach the set pressure until the alloy liquid reaches the solidification time in the mold cavity 21. The central control console 11 sends a signal to control the shut-off mechanism 23 to pull the plunger 25 back to the inside of the guide sleeve 24, open the exhaust pipe to adjust the pressure of the tank 20 to normal pressure, disassemble the tank 20 and the mold 21, and clean them.

[0011] In step 5, during the solidification stage, positive or negative pressure that meets the parameter requirements may be applied to the outside of the mold 21 according to the process requirements, so that the alloy inside the mold 21 solidifies under the pressure; the pressure range is -0.01MPa~0.8MPa. The solidification time of the alloy liquid inside the mold ranges from 0 to 1000s.

[0012] In the solidification stage of step 5, the positive / negative pressure building time inside the tank body 20 is ≤ 3 minutes, so as to ensure that the alloy inside the casting mold 21 solidifies under the action of pressure.

[0013] During the solidification and pressurization process in step 5, the tank air inlet pipe 18 can not only introduce compressed air, argon, nitrogen and other compressed gases into the tank 20. If the casting material is a metal mold, liquid nitrogen can also be used as a rapid gasification-quenching and pressurization medium to adjust the temperature of the outside of the casting 21 locally or as a whole, and change the solidification speed and temperature gradient of the alloy liquid inside the casting 21; if the alloy material is a magnesium alloy, mixed protective gas can also be introduced into the tank 20 to achieve alloy solidification pressurization, liquid surface protection and flame retardancy, and the tank exhaust pipe 19 can achieve exhaust of the casting 21 and vacuumization of the tank 20.

[0014] At least one liquid riser 15 is installed on the furnace cover 14 of the counter-gravity casting equipment 1. When there are at least two liquid riser 15, alloy liquid can be transported synchronously in multiple zones.

[0015] The present invention can perform counter-gravity filling in the open riser casting mold 21, which can not only extract high-quality alloy liquid in the middle of the crucible 13 for stable filling and reduce slag inclusion; it can also quickly receive external pressure changes and transmit them to the inside of the casting, reduce pinholes, and enhance shrinkage compensation; it can also timely remove the gas inside the cavity, improve the forming ability of thin-walled complex structures, and avoid problems such as pores and cold shuts; it can also effectively reduce the concentration of combustible atmosphere generated by thermal decomposition of the sand mold in the cavity. The above-mentioned device and method are generally applicable to various casting molds such as sand molds and metal molds, and can be applied to various counter-gravity casting processes such as low pressure / differential pressure / pressure regulation, fully automatic operation, high production efficiency, stability and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the overall structure of the riser anti-gravity filling integral solidification process device; Figure 2 It is a schematic diagram showing the installation relationship of the mold 21, the contact 22, the shut-off mechanism 23, the guide sleeve 24, the plunger 25, etc. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with the embodiments and the accompanying drawings, but is not limited thereto.

[0018] Example 1 The large aluminum alloy cabin casting is solidified under normal pressure after low-pressure casting by using an open riser anti-gravity mold filling integral solidification process device. The key technology is: the open riser anti-gravity mold filling integral solidification process device includes an anti-gravity casting device 1, a mold 21, a contact 22, a cut-off mechanism 23, a guide sleeve 24, and a plunger 25; wherein: The casting mold is a sand mold, and the casting mold 21 is composed of a bottom gate layer (lower box), an upper structure layer (middle box and upper box) and an internal structure (inner core). The top of the upper structure layer (upper box) in the casting mold 21 is provided with an open riser; The contact is a 2.5-square-meter national standard pure copper wire wrapped with an insulating fire-resistant tube, which is placed 30 mm vertically downward from the upper end of the open riser of the upper box of the casting, and the end of the wire extends out of the upper box of the casting and enters the open riser; A single guide sleeve with an overall size of φ120×800mm and a wall thickness of 10mm is embedded in sections in the upper box, inner core and lower box sand mold of the casting mold, and is accurately positioned using positioning pins to form a guide sleeve structure that penetrates the casting mold. After the casting mold is closed, a plunger with a size of φ98×1000mm is placed inside the guide sleeve from the top to ensure that the plunger can move freely up and down inside the guide sleeve. The bottom end face of the plunger is a 50×10mm bevel, and the inner diameters of the riser pipe and the casting lower box gate are both 80mm. The center of the upper and lower end faces of the plunger is located on the same axis as the center of the riser pipe mouth and the center of the gate in the anti-gravity casting equipment 1; A hydraulic cylinder is used as a cut-off mechanism in the anti-gravity casting process of large aluminum alloy cabin castings. The hydraulic cylinder is fixed above the guide sleeve and connected to the plunger to control the ejection or retraction of the plunger in the guide sleeve.

[0019] The anti-gravity casting equipment is a low-pressure casting machine, which includes a central control console, a smelting furnace, a crucible, a furnace cover, a riser, and a tank body; wherein: The lower part adopts a smelting furnace as the installation base, the crucible is arranged in the inner cavity of the smelting furnace, the single melting weight is 600Kg, and most of the riser tube with an inner diameter of 80mm is arranged in the inner cavity of the crucible; the smelting furnace is provided with a smelting furnace air inlet pipe and a smelting furnace exhaust pipe, and both the air inlet and exhaust pipes are British 2-inch pipes; A furnace cover is arranged around the upper part of the riser pipe to close the space above the smelting furnace; The air inlet pipe and exhaust pipe of the smelting furnace are connected to the central control console.

[0020] The specific process includes the following steps and contents: Step 1, preparation of a large aluminum alloy cabin casting mold: a gate is made at the bottom gate layer of the mold to ensure that the bottom surface of the bottom gate layer is horizontal, a guide sleeve is pre-placed inside the mold and fixed, and a plunger is pre-placed inside the guide sleeve to ensure that the axes of the plunger, guide sleeve, and gate coincide and are perpendicular to the bottom horizontal surface of the bottom gate layer; Step 2, equipment installation: After the alloy is smelted in the crucible, cover the furnace cover, insert the riser pipe into the alloy liquid in the crucible in the furnace through the furnace cover, fix the riser pipe flange on the furnace cover, keep the center of the bottom gate of the mold and the center of the riser pipe mouth in the same vertical axis, place the mold on the furnace cover and the riser pipe and tighten it, connect the contact on the top of the mold with the wire of the central console, and install the cut-off mechanism on the guide sleeve and connect it to the plunger; Step 3, anti-gravity filling: the central console controls the opening of the air inlet pipe of the smelting furnace, and introduces compressed air into the smelting furnace to push the alloy liquid into the mold cavity through the riser and the gate. When the alloy liquid reaches the inside of the riser in the upper structure layer, the contact is connected and transmits a signal to the central console; Step 4, shutoff and pressure relief: When the alloy liquid reaches the set position, the central console sends a signal, the shutoff mechanism starts, pushes the plunger to move down quickly in the guide sleeve, enters the inside of the casting mold to block the gate, and cuts off the connection between the alloy liquid in the riser and the casting mold. Then, the counter-gravity casting equipment controls the exhaust pipe to open, and the pressure in the melting furnace is relieved to normal pressure; Step 5, solidification: while the smelting furnace is depressurized, the plunger continues to block the gate and does not move until the alloy liquid is completely solidified in the casting cavity. The central console sends a signal to control the shut-off mechanism to pull the plunger back into the guide sleeve, open the exhaust pipe to adjust the gas pressure in the smelting furnace to normal pressure, disassemble the casting, clean it and wait for the next furnace test.

[0021] This embodiment adopts an open riser anti-gravity filling overall solidification process device to perform low-pressure anti-gravity filling on large-sized aluminum alloy cabin castings and then solidify them under normal pressure. It extracts high-quality alloy liquid in the middle of the crucible for smooth filling, reduces slag inclusions, and promptly removes gas from the cavity, thereby improving the forming ability of thin-walled complex structures inside large-sized cabins, avoiding problems such as air holes and cold shuts, solving the forming problem of thin-walled areas of large-sized aluminum alloy cabin castings, and improving the metallurgical quality of castings.

[0022] Example 2 A large-size thick-walled aluminum alloy box casting adopts an open riser anti-gravity filling integral solidification process device for anti-gravity filling and rapid pressurization solidification. The difference between it and Example 1 is that: The contact is a temperature sensor wrapped with an insulating refractory tube, which is placed 100 mm vertically downward from the upper end of the open riser of the upper box of the casting, and the sensor end extends out of the upper box of the casting and enters the open riser; Four guide sleeves with an overall size of φ60×600mm and a wall thickness of 5mm are pre-embedded in the upper box, inner core and lower box sand mold of the mold in three sections. They are accurately positioned using positioning pins to form a guide sleeve structure that penetrates the mold at four locations. After the mold is closed, four plungers with a size of φ58×700mm are placed inside the guide sleeves from the top to ensure that the plungers can move freely up and down inside the guide sleeves. The bottom end face of the plunger is a 50×10mm chamfer. The inner diameter of the four gates in the lower box of the mold is 40mm. The center of the upper and lower end faces of the plunger and the center of the gate in the anti-gravity casting equipment are located on the same axis; A weight-top plate-spring mechanism is used as the shut-off mechanism for the anti-gravity casting process of large-size thick-walled boxes. The top plate is connected to four plungers at the same time and the four plungers are located on the same horizontal plane. The weight is pressed down to push the plunger in the guide sleeve out, and the weight upper spring pushes the plunger in the guide sleeve back.

[0023] A furnace cover is arranged around the upper part of the riser pipe to close the space above the smelting furnace, and a tank body 20 for closing the upper space is arranged above the furnace cover, and the size of the tank body is 2500×3500mm; The tank body is provided with a tank body air inlet pipe and a tank body exhaust pipe, and both the air inlet and exhaust pipes are British 2-inch pipes; The specific steps and contents are different from those in Example 1 in that: In step 1, during the mold preparation process: there are 4 gates in the bottom gate layer of the mold to ensure that the bottom surface of the bottom gate layer is level, and 4 plungers are pre-placed in different guide sleeves; In the process of counter-gravity filling in step 3: the temperature sensor continuously monitors the temperature of the open riser area. When the alloy liquid reaches the inside of the open riser in the upper structure layer, the temperature measured by the temperature sensor rises rapidly. In the process of shutoff and pressure relief in step 4: the central console continuously receives the temperature sensor signal, recognizes the rapid rise in temperature, sends a signal, the shutoff mechanism is activated, and the plunger is pushed down quickly in the guide sleeve to enter the casting mold to block the gate. After the connection between the alloy liquid in the riser and the casting mold is cut off, the counter-gravity casting equipment controls the exhaust pipe to open, and the pressure in the melting furnace is relieved to normal pressure; In step 5 solidification process: while the smelting furnace is depressurized, the plunger continues to block the pouring gate and does not move. The counter-gravity casting equipment opens the tank air inlet pipe according to the process requirements and sprays liquid nitrogen into the tank to make the pressure in the tank reach 0.6MPa within 3 minutes until the alloy liquid is completely solidified in the casting cavity. The exhaust pipe is opened to adjust the tank pressure to normal pressure, and the central console sends a signal to control the shut-off mechanism to pull the plunger back into the guide sleeve.

[0024] The effect of this embodiment differs from that of embodiment 1 in that it not only has the functions of embodiment 1 such as ensuring alloy quality, improving filling capacity, and enhancing exhaust, but also realizes multi-point filling and synchronous cutting off of large-size castings, improves filling speed and filling capacity, and realizes solidification of large-size aluminum alloy thick-walled box castings under pressure through rapid pressurization inside the tank body, further improving the density and organizational properties of the castings.

[0025] Example 3 A magnesium alloy shell casting adopts an open riser anti-gravity filling integral solidification process device to perform anti-gravity filling under atmosphere protection and then rapid pressurization solidification, which is different from Example 1 in that: A single guide sleeve with an overall size of φ60×600mm and a wall thickness of 5mm is embedded in the upper box, inner core and lower box sand mold in sections, and a plunger 25 with a size of φ58×1000mm is placed inside the guide sleeve 24 from the top to ensure that the plunger can move freely up and down inside the guide sleeve. The bottom end face of the plunger is a 50×10mm bevel, and the inner diameter of the riser and the gate of the lower box of the mold are both 40mm; The anti-gravity casting equipment is a low-pressure casting machine, the lower part of which uses a crucible in a melting furnace to melt a magnesium alloy weighing 300 kg at a time; a tank body 20 for sealing the upper space is arranged above the furnace cover, the tank body size is 2500×3500 mm, and a tank body air inlet pipe and a tank body exhaust pipe are arranged on the tank body. The tank body air inlet pipe is externally connected to a magnesium alloy mixed protective gas with a pressure of 0.4~0.8MPa.

[0026] The specific steps and contents are different from those in Example 1 in that: During the solidification process of step 5: while the smelting furnace is depressurized, the plunger continues to block the gate and does not move. The counter-gravity casting equipment opens the tank air inlet pipe according to the process requirements and sprays high-pressure mixed protective gas into the tank to make the pressure in the tank reach 0.6MPa within 3 minutes until the magnesium alloy liquid is completely solidified in the casting cavity. The exhaust pipe is opened to adjust the tank pressure to normal pressure, and the central console sends a signal to control the shut-off mechanism to pull the plunger back into the guide sleeve.

[0027] The effect of this embodiment differs from that of embodiment 1 in that it not only has the functions of embodiment 1 such as ensuring alloy quality, improving filling capacity, and strengthening exhaust, but also the rapid discharge of heated gas from the sand mold during the magnesium alloy filling process can effectively reduce the "choking" defect of the casting, and the blowing of high-pressure mixed protective gas during the solidification process can not only realize pressurized solidification and improve the density and organizational properties of the casting, but also effectively inhibit the oxidation combustion during the solidification process of the magnesium alloy, thereby greatly ensuring production safety.

[0028] Example 4 A magnesium alloy casting adopts an open riser anti-gravity filling integral solidification process device to carry out a metal mold anti-gravity filling negative pressure solidification process, which is different from Example 1 in that: The casting mold is a metal mold, which consists of a lower mold and an upper mold, and an exposed riser is arranged on the top of the upper mold; The specific steps and contents are different from those in Example 3 in that: In step 1, in the mold preparation: the metal mold is divided into a lower mold (bottom gate layer) and an upper mold (upper structure layer), a single gate is designed in the central area of ​​the bottom of the lower mold, a guide sleeve is pre-placed inside the upper mold of the mold and fixed, a plunger is pre-placed inside the guide sleeve, and the entire mold is located inside the tank body; During the equipment installation process in step 2: a servo motor + screw is used as the cut-off mechanism, which is installed above the guide sleeve, and the screw is connected to the plunger; the tank exhaust pipe is externally connected to a vacuum pump.

[0029] During the flow cut-off and pressure relief process in step 4: the servo motor drives the screw to push out, so that the plunger 25 moves downward synchronously in the guide sleeve 24; The difference between the effects of this embodiment and embodiment 3 is that the overall solidification process of the magnesium alloy metal mold open riser anti-gravity filling is realized.

[0030] In addition to the above examples, there are other methods in which a pressure device can push the plunger 25 to vertically block the gate, all of which are within the scope of protection of this patent application.

Claims

1. An open riser anti-gravity filling integral solidification process device, characterized in that: It comprises an anti-gravity casting device (1), a casting mold (21), a contact point (22), a cut-off mechanism (23), a guide sleeve (24), and a plunger (25); wherein: The casting mold (21) is one of the following or a combination thereof: a sand mold, a metal mold, a ceramic mold, the casting mold (21) is composed of a bottom gate layer, an upper structure layer and an internal structure, the bottom gate layer is the lower box, the upper structure layer is the middle box and the upper box, and the internal structure is the inner core; the top of the middle and upper structure layer of the casting mold (21), i.e., the upper box, is provided with an open riser; The contact (22) is a sensor capable of transmitting a signal, and the contact (22) is located inside the open riser of the casting mold (21); The guide sleeve (24) is fixedly installed inside the casting mold (21), and the plunger (25) is located inside the guide sleeve (24); the number of the guide sleeves (24) and the plunger (25) corresponds to the number of the openings and gates of the liquid riser (15) in the counter-gravity casting device (1); the axis of the guide sleeve (24) and the plunger (25) is perpendicular to the installation plane of the liquid riser (15), and is located on the same axis as the center of the opening of the liquid riser (15) and the center of the gate in the counter-gravity casting device (1); The shutoff mechanism (23) is installed above the guide sleeve (24) and is connected to the plunger (25). The shutoff mechanism (23) is used to control the ejection or retraction of the plunger (25) in the guide sleeve (24).

2. The open riser counter-gravity filling integral solidification process device according to claim 1, characterized in that: The anti-gravity casting equipment (1) comprises a central control console (11), a smelting furnace (12), a crucible (13), a furnace cover (14), a liquid riser (15), and a tank body (18); wherein: The lower part thereof is installed on a smelting furnace (12), a crucible (13) is arranged in the inner cavity of the smelting furnace (12), and most of the riser pipe (15) is arranged in the inner cavity of the crucible (13); the smelting furnace (12) is provided with a smelting furnace air inlet pipe (16) and a smelting furnace exhaust pipe (17); A furnace cover (14) for sealing the space above the smelting furnace (12) is arranged around the upper part of the riser pipe (15); a tank body (20) for sealing the space above is arranged above the furnace cover (14); and a tank body air inlet pipe (18) and a tank body exhaust pipe (19) are provided on the tank body (20); The smelting furnace air inlet pipe (16), the smelting furnace exhaust pipe (17), the tank air inlet pipe (18), and the tank exhaust pipe (19) are all connected to a central control console (11); The tank exhaust pipe (19) is externally connected to a vacuum pump for evacuating the tank (20).

3. The open riser anti-gravity filling integral solidification process device according to claim 2, characterized in that: The open riser counter-gravity filling integral solidification process device meets the following requirements: First, the mold preparation unit meets the following requirements: The bottom gate layer of the casting mold (21) is designed with n gates, n≥1; and the bottom surface of the bottom gate layer is required to be horizontal; the guide sleeve (24) is pre-placed inside the casting mold (21) and fixed, and the plunger (25) is pre-placed inside the guide sleeve (24), and it is ensured that the axes of the guide column, the guide sleeve (24) and the gate coincide and are perpendicular to the bottom horizontal surface of the bottom gate layer; Second, the installation of the open riser anti-gravity filling integral solidification process device meets the following requirements: The upper end of the liquid riser (15) is connected downward to the alloy liquid in the crucible (13) in the furnace through the furnace cover (14), and the flange of the liquid riser (15) is fixed on the furnace cover (14); the center of the bottom gate of the casting mold (21) and the center of the mouth of the liquid riser (15) are required to maintain a unified vertical axis; The casting mold (21) is placed above the furnace cover (14) and the liquid riser (15) and is fastened, the contact (22) above the casting mold (21) is connected to the wire of the central control console (11), and the cut-off mechanism (23) is installed above the guide sleeve (24) and is connected to the plunger (25); Third, the anti-gravity filling part meets the following requirements: The central control panel (11) can control the opening of the air inlet pipe (16) on the smelting furnace to introduce compressed air into the smelting furnace (12) so as to push the alloy liquid to enter the mold cavity of the casting mold (21) through the liquid riser (15) and the pouring gate in sequence; When the alloy liquid reaches the interior of the open riser in the upper structural layer, the contact (22) continuously monitors and transmits an alloy liquid level signal to the central control console (11); Fourth, the interception and pressure relief shall meet the following requirements: When the alloy liquid reaches the set position in the late stage of counter-gravity filling, the central control panel (11) sends a signal, the shut-off mechanism (23) starts, and the plunger (25) is pushed downward quickly in the guide sleeve (24), enters the interior of the casting mold (21) to block the pouring gate, and cuts off the connection between the alloy liquid in the riser pipe (15) and the casting mold (21); then the counter-gravity casting equipment (1) controls the exhaust pipe to open, and the pressure in the melting furnace (12) is released to normal pressure; Fifth, the open riser anti-gravity filling integral solidification process device meets the following requirements during the solidification stage: While the pressure of the fourth smelting furnace (12) is being released, the plunger (25) continues to block the pouring gate without moving, and the counter-gravity casting equipment (1) opens the tank air inlet pipe (19) or the vacuum pipe according to the process requirements to make the internal pressure of the tank (18) reach the set pressure, until the alloy liquid is completely solidified in the mold cavity (21), and the central control panel (11) sends a signal to control the shut-off mechanism (23) to pull the plunger (25) back to the inside of the guide sleeve (24); then, the exhaust pipe is opened to adjust the pressure of the tank (18) to normal pressure, and then the tank (18) and the mold (21) are disassembled, and the relevant parts are cleaned for later use.

4. An open riser mold counter-gravity filling overall solidification process method using the open riser counter-gravity filling overall solidification process device according to claim 1, characterized in that: The specific process of this method includes the following steps and contents in sequence: Step 1, mold preparation: design n gates at the bottom gate layer of the mold (21) according to actual needs, n ≥ 1, ensure that the bottom surface of the bottom gate layer is horizontal, pre-place the guide sleeve (24) inside the mold (21) and fix it, pre-place the plunger (25) inside the guide sleeve (24), ensure that the guide column, the guide sleeve (24), and the gate axis coincide and are perpendicular to the bottom horizontal surface of the bottom gate layer; Step 2, equipment installation: after the alloy is smelted in the crucible (13), the furnace cover (14) is closed, the riser pipe (15) is inserted into the alloy liquid in the crucible (13) in the furnace through the furnace cover (14), the flange of the riser pipe (15) is fixed to the furnace cover (14), the center of the bottom gate of the casting mold (21) and the center of the mouth of the riser pipe (15) are kept on the same vertical axis, the casting mold (21) is placed on the top of the furnace cover (14) and the riser pipe (15) and fastened, the contact (22) above the casting mold (21) is connected to the wire of the central control console (11), and the cut-off mechanism (23) is installed above the guide sleeve (24) and connected to the plunger (25); Step 3, anti-gravity filling: the central control console (11) controls the air inlet pipe of the smelting furnace (12) to open, and introduces compressed air into the smelting furnace (12), so as to push the alloy liquid into the mold cavity of the casting mold (21) through the liquid riser (15) and the gate in sequence. When the alloy liquid reaches the inside of the riser in the upper structure layer, the contact (22) transmits an alloy liquid level signal to the central control console (11); Step 4, shutoff and pressure relief: when the alloy liquid reaches the set position, the central control console (11) sends a signal, the shutoff mechanism (23) starts, and the plunger (25) is pushed downward quickly in the guide sleeve (24), enters the casting mold (21) to block the pouring gate, and after the alloy liquid in the riser (15) is cut off from being connected to the casting mold (21), the counter-gravity casting equipment (1) controls the exhaust pipe to open, and the pressure in the melting furnace (12) is relieved to normal pressure; Step 5, solidification: while the smelting furnace (12) is depressurized, the plunger (25) continues to block the pouring gate and does not move. The counter-gravity casting equipment (1) opens the tank air inlet pipe (19) or the vacuum pipe according to the process requirements to make the internal pressure of the tank (18) reach the set pressure. After the alloy liquid is completely solidified in the mold cavity of the casting mold (21), the central control panel (11) sends a signal to control the shut-off mechanism (23) to pull the plunger (25) back to the inside of the guide sleeve (24). After the exhaust pipe is opened to adjust the pressure of the tank (18) to normal pressure, the tank (18) and the casting mold (21) are disassembled and cleaned.

5. The method for overall solidification of an open riser mold by counter-gravity filling according to claim 4, characterized in that: In step 5, during the solidification stage, it is allowed to apply positive pressure or negative pressure that meets the parameter requirements to the outside of the mold (21) according to the process requirements, so that the alloy inside the mold (21) solidifies under the pressure; the pressure range is -0.01MPa~0.8MPa.

6. The method for overall solidification of an open riser mold by counter-gravity filling according to claim 5, characterized in that: In the solidification stage of step 5, the positive pressure / negative pressure building time inside the tank body (20) is ≤3 minutes, so as to ensure that the alloy inside the casting mold (21) solidifies under the action of pressure.

7. The open riser anti-gravity mold filling integral solidification method according to any one of claims 4 to 6, characterized in that: In step 5, during the solidification and pressurization process, the tank air inlet pipe (19) can not only introduce compressed air into the tank (18), but also spray a medium that can quickly gasify, quench and pressurize the surface of the metal mold / ceramic mold inside the tank (18), thereby adjusting the temperature of the outside of the mold (21) locally or as a whole, and changing the solidification speed and temperature gradient of the alloy liquid inside the mold (21); it can also introduce a mixed protective gas into the tank (18) to achieve solidification pressurization, liquid surface protection and flame retardancy of the magnesium alloy, and the tank exhaust pipe (20) can achieve vacuum inside the tank (18) and strengthen the exhaust of the mold (21).

8. The open riser counter-gravity filling integral solidification method according to claim 7, characterized in that: At least one liquid riser (15) is installed on the furnace cover (14) of the counter-gravity casting equipment (1); when there are at least two liquid riser pipes (15), synchronous transportation of alloy liquid in multiple zones can be achieved.

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