Pressure-regulating mold-filling pressurized solidification method

Abstract

The invention discloses a pressure-regulating mold-filling pressurization solidification device which comprises a pressure tank, a lifting mechanism, an electric furnace, a pneumatic control system, an electric control system and a bracket, wherein the pressure tank is divided into a pressure tank upper tank, a pressure tank lower tank and a middle partition plate; the pressure tank adopts a vertical structure; the pressure-bearing range of the pressure-bearing material is 0.5-2 MPa; the pressure-regulating mold-filling pressurized solidification method using the pressure-regulating mold-filling pressurized solidification device can be applied to processes such as low-pressure casting, counter-pressure casting, pressurized solidification after vacuum-pumping mold-filling, pressurized solidification after vacuum-pumping mold-filling of an upper tank of a pressure tank and the like. According to the method, the alloy mold filling capacity is improved, mold filling of a large-plane thin-wall complex structure is achieved, mold core exhaust is effectively enhanced, and the air hole defect and the chocking problem of a casting are greatly reduced. And the compactness of the alloy structure is improved, the shrinkage porosity defect of the casting is reduced, and the mechanical property of the casting is remarkably improved. And the comprehensive technical effect is excellent.

Description

Technical Field

[0001] The present invention relates to the fields of scheme design, special device design and application technology of the pressure-regulating filling and pressurized solidification method, and particularly relates to a pressure-regulating filling and pressurized solidification method. Background Art

[0002] In the prior art, low-pressure casting is a casting process in which a low pressure is applied to the surface of molten metal, so that it fills the mold smoothly from bottom to top along the riser tube and solidifies under the action of pressure. However, this process has limitations such as low production efficiency, high equipment cost and limited production of large castings. At the same time, due to the complexity of pressure and temperature control in the casting process, the deformation of castings is difficult to accurately predict and control, the alloy microstructure may not be dense enough, and there may even be internal defects such as microcracks, resulting in an increase in the brittleness of castings.

[0003] To solve these problems, differential pressure casting came into being. On the basis of low-pressure casting, by adding a sealing cover outside the mold to form a pressure difference, the liquid metal crystallizes and solidifies under a higher pressure, thereby improving the density and mechanical properties of the casting. However, differential pressure casting also faces challenges, such as high equipment complexity, strict high-temperature sealing requirements, and difficulty in controlling the size and shape of castings. In addition, the properties of the alloy microstructure may also be affected by defects such as gas holes, shrinkage cavities and slag inclusions, which may be caused by excessive gas content in the alloy, improper casting process or poor ventilation of the mold. In view of the limitations of the above processes, it is particularly urgent to develop a pressure-regulating filling and pressurized solidification device and its method to meet the requirements of complete forming and quality control of large and complex structure castings, thereby improving the overall efficiency of the casting process and the product quality.

[0004] In addition, thin-walled castings often face a challenge during the casting process: due to their thin walls and complex structures, the molten metal is significantly affected by surface tension during filling, resulting in difficulty in completely filling the cavity. Surface tension, as a result of the unbalanced intermolecular attraction in the liquid surface layer, will hinder the free flow of the molten metal. Especially when encountering small or complex structures, the molten metal often cannot overcome the resistance of surface tension and is difficult to completely fill the mold. This problem is particularly prominent in the manufacture of thin-walled castings because the thin-wall structure has higher requirements for the fluidity and filling ability of the molten metal. When the molten metal is hindered by surface tension, it will not only lead to incomplete filling of the casting, but also may cause a series of defects such as cold shut and misrun, seriously affecting the quality and performance of the casting.

[0005] To solve this difficult problem, the vacuum filling technology came into being. The vacuum filling technology effectively reduces the influence of surface tension during the metal liquid filling process by introducing a vacuum environment during casting. Under vacuum conditions, the intermolecular attraction on the surface of the metal liquid weakens, and the surface tension decreases accordingly, making the metal liquid flow and fill the cavity more easily. The vacuum environment can also reduce the oxidation and gas entrainment of the metal liquid during the filling process, further improving the quality and performance of the casting. Therefore, adopting the vacuum filling technology is an effective way to solve the problem that thin-walled castings are difficult to fill due to the influence of surface tension. Through this technology, the filling ability and quality stability of thin-walled castings can be significantly improved, providing strong support for the high-quality development of the casting industry.

[0006] People urgently hope to obtain a pressure-regulating filling and pressurized solidification device with better technical effects and a pressure-regulating filling and pressurized solidification method using it. Summary of the Invention

[0007] The present invention provides a pressure-regulating filling and pressurized solidification method. It has both single-tank control and double-tank control. In the case of double-tank control, the upper and lower tanks (i.e., the upper tank of the pressure tank and the lower tank of the pressure tank) have independent functions of controlling pressurization, exhaust, vacuum pumping, etc., and can realize 4 casting control methods, namely low-pressure casting, differential-pressure casting, pressurized solidification after vacuum filling of the upper and lower tanks, and pressurized solidification after vacuum filling of the upper tank.

[0008] The technical solution of the present invention is as follows:

[0009] The present invention mainly relates to a pressure-regulating filling and pressurized solidification method, and its technical key is:

[0010] The pressure-regulating filling and pressurized solidification method uses a special pressure-regulating filling and pressurized solidification device; the pressure-regulating filling and pressurized solidification device includes a pressure tank, a lifting mechanism, an electric furnace, a pneumatic control system, an electric control system, and a bracket; among them: the pressure tank is divided into two parts: the upper tank of the pressure tank, the lower tank of the pressure tank, and the middle partition; the electric furnace is located in the lower tank of the pressure tank, and the upper tank of the pressure tank and the lower tank of the pressure tank are fixedly connected as a whole through the middle partition; the upper tank of the pressure tank is arranged above the middle partition; the middle partition is arranged above the lower tank of the pressure tank; the upper tank of the pressure tank, the lower tank of the pressure tank, and the middle partition are connected into a complete pressure vessel, the sealing ring uses an O-shaped fluororubber sealing ring, and the locking structure uses a wedge-shaped lock to ensure airtightness; the pressure tank structure adopts a vertical structure; and its pressure-bearing range is 0.5 - 2 MPa;

[0011] The upper pressure tank, the middle partition plate, and the lower pressure tank are arranged in the internal space of the bracket with a frame structure; the upper pressure tank is arranged on the bracket through a lifting mechanism; the lifting mechanism includes a hoisting unit and a translation unit; the lifting mechanism is a gantry lifting and translation vehicle + hydraulic system; the lifting mechanism contains a hydraulic lifting mechanism or / and a motor drive mechanism, and its motor control can achieve precise positioning of can closing; it has the functions of hoisting and translating the upper pressure tank, the middle partition plate, and the low-pressure gasket; the lifting of the upper pressure tank and the middle partition plate adopts hydraulic lifting; the translation has multi-stage speed control to achieve precise positioning of can closing;

[0012] The pneumatic control system is connected to the upper pressure tank and the lower pressure tank in the pressure tank; the electric control system is respectively connected to the pressure tank, the lifting mechanism, the electric furnace, the pneumatic control system, and the bracket;

[0013] The electric furnace is used to melt the alloy liquid. The electric furnace includes: a melting electric furnace, a crucible, a riser pipe, a furnace shell, and a sealing groove; the electric furnace is heated by a three-phase power supply, the heating element is a heating resistance belt, the furnace wire is selected as a high-temperature heating belt, and the furnace chamber in the furnace shell is an integrated ceramic fiber furnace chamber; the electric furnace is internally provided with temperature measurement points; the inlet and exhaust pipe orifices of the pneumatic control system are located between the tank body of the pressure tank and the furnace body of the electric furnace, and the furnace shell of the electric furnace is separately manufactured from the tank body of the pressure tank;

[0014] The upper pressure tank is hoisted and transported by the lifting mechanism. Before pouring, it is hoisted by the lifting mechanism directly above the electric furnace and lowered above the sand mold; the sand mold is placed above the middle partition plate inside the upper pressure tank.

[0015] The pressure-regulating filling, pressurizing, and solidifying method can be applied to the field of low-pressure casting. During its implementation and application in the field of low-pressure casting, it successively includes the following steps and contents:

[0016] Step 1, low-pressure filling: The lower pressure tank intakes air, adjusts the pressure, and the alloy liquid enters the cavity at a set speed and fills the cavity;

[0017] Step 2, shell-forming pressurization: The lower pressure tank continues to intake air, adjusts the air pressure, and changes according to the set shell-forming pressurization pressure and shell-forming pressurization time to complete shell-forming pressurization;

[0018] Step 3, crystallization pressurization: The lower pressure tank continues to intake air, adjusts the air pressure, and changes according to the crystallization pressurization pressure and shell-forming pressurization time until crystallization pressurization is completed;

[0019] Step 4, pressure holding and solidifying: Hold the pressure for a set time until the casting solidifies under pressure;

[0020] Step 5, pressure relief: After the pressure holding ends, the lower pressure tank is depressurized to normal pressure, and the mold is taken out.

[0021] The pressure-regulating filling, pressurizing, and solidifying method is alternatively applied to the differential pressure casting process. A preferred specific process thereof successively includes the following steps and contents:

[0022] Step 1, overall pressurization: The upper tank and the lower tank of the pressure tank are simultaneously filled with gas and pressurized synchronously.

[0023] Step 2, mold filling: Select the mode of filling gas into the lower tank of the pressure tank or relieving pressure from the upper tank of the pressure tank to create a pressure difference between the upper tank and the lower tank of the pressure tank. The alloy liquid enters the cavity at a set speed and fills the cavity.

[0024] Step 3, shell-forming pressurization: Select the mode of continuing to fill gas into the lower tank of the pressure tank or continuing to relieve pressure from the upper tank of the pressure tank, adjust the air pressure, and change according to the shell-forming pressurization pressure and shell-forming pressurization time until the shell-forming pressurization is completed.

[0025] Step 4, crystallization pressurization: The lower tank of the pressure tank continues to fill gas or the upper tank of the pressure tank continues to relieve pressure, adjust the air pressure, and change according to the crystallization pressurization pressure and shell-forming pressurization time until the crystallization pressurization is completed.

[0026] Step 5, pressure holding and solidification: Hold the pressure for a set time until the casting solidifies under a higher pressure.

[0027] Step 6, pressure relief: After the pressure holding is completed, the upper tank and the lower tank of the pressure tank are simultaneously exhausted to relieve pressure to atmospheric pressure, and the mold is taken out.

[0028] The described pressure regulating, mold filling, and pressurization solidification method is alternatively applied to the process of pressurization solidification after vacuum filling.

[0029] The specific process of the pressurization solidification process after vacuum filling in the upper tank and the lower tank of the pressure tank sequentially includes the following steps and contents:

[0030] Step 1, overall vacuum pumping: The upper tank and the lower tank of the pressure tank are pumped with vacuum synchronously.

[0031] Step 2, overall vacuum mold filling: The lower tank of the pressure tank is filled with gas alone, and the vacuum degree is adjusted to create a pressure difference between the upper tank and the lower tank of the pressure tank. The alloy liquid enters the cavity at a set speed and fills the cavity.

[0032] Step 3, shell-forming pressurization: The lower tank of the pressure tank is filled with gas, and the air pressure is adjusted and changed according to the shell-forming pressurization pressure and shell-forming pressurization time until the shell-forming pressurization is completed.

[0033] Step 4, overall pressurization: The upper tank and the lower tank of the pressure tank are simultaneously filled with gas to synchronously increase the pressure of the upper tank and the lower tank of the pressure tank to the set pressure.

[0034] Step 5, crystallization pressurization: The lower tank of the pressure tank continues to fill gas, and the air pressure is adjusted and changed according to the crystallization pressurization pressure and shell-forming pressurization time until the crystallization pressurization is completed.

[0035] Step 6, pressure holding and solidification: Hold the pressure for a set time until the casting solidifies under a higher pressure.

[0036] Step 7, pressure relief: After the pressure holding is completed, the upper and lower pressure tanks exhaust air simultaneously to relieve pressure to atmospheric pressure, and then the mold is taken out.

[0037] The pressure regulating, filling, pressurizing and solidifying method is alternatively applied to the process of vacuum filling the upper pressure tank and then pressurizing and solidifying. The specific process sequentially includes the following steps and contents:

[0038] Step 1, vacuum filling of the upper pressure tank: The lower pressure tank maintains atmospheric pressure, and the upper pressure tank is evacuated alone to form a pressure difference between the upper and lower pressure tanks. The alloy liquid is sucked into the cavity at a set speed until the alloy fills the mold, and the filling is completed.

[0039] Step 2, shell building and pressure increasing: The upper pressure tank continues to intake air, and the air pressure is adjusted to complete shell building and pressure increasing according to the changes in the shell building and pressure increasing pressure and time.

[0040] Step 3, overall pressurization: The upper and lower pressure tanks intake air simultaneously to synchronously increase the pressure of the upper and lower pressure tanks to the set pressure.

[0041] Step 4, crystallization pressure increasing: The upper pressure tank continues to intake air, and the air pressure is adjusted to complete crystallization pressure increasing according to the changes in the crystallization pressure increasing pressure and shell building and pressure increasing time.

[0042] Step 5, pressure holding and solidifying: Pressure is held for a set time until the casting solidifies under a high pressure.

[0043] Step 6, pressure relief: After the pressure holding is completed, the upper and lower pressure tanks exhaust air simultaneously to relieve pressure to atmospheric pressure, and then the mold is taken out.

[0044] The pressure regulating, filling, pressurizing and solidifying method meets one or a combination of the following requirements:

[0045] Firstly, the pressure regulating, filling, pressurizing and solidifying device meets the following requirements: The electric furnace is installed inside the lower pressure tank and is flush with the ground; The maximum heating temperature of the electric furnace is 1000 - 1500 °C, the temperature uniformity is ≤ ±10 °C, and the heating power is 50 - 80 kW; The electric furnace is equipped with temperature measurement points, and the temperature on the furnace shell surface is ≤ the ambient temperature + 30 °C; The inlet and exhaust pipe orifices in the pneumatic control system are located between the tank body and the furnace body, and the furnace body is separated from the tank body.

[0046] Secondly, the pressure control accuracy of the pneumatic control system during the alloy filling stage is ≤ ±5 KPa, the maximum liquid rising speed during the alloy filling stage is 20 - 200 mm / s in terms of aluminum, the pressure holding and control accuracy is ≤ ±1 KPa, the pressure holding time for the casting crystallization and solidification is 0 - 60 min, during the solidification pressurizing process, the pressure rising speed is ≥ 100 KPa / min, and the deviation between the "pressure difference - time" curve and the set curve is ≤ ±5 KPa.

[0047] Thirdly, under the condition of cold state of the empty furnace, the internal vacuum degree requirements of the upper pressure tank and the lower pressure tank are 0.1 Pa to 20 KPa; under working conditions, the internal vacuum degree of the upper and lower tanks can be maintained at 0.1 KPa to 50 KPa (absolute vacuum degree), and the vacuum pumping and pressure building time of the inner cavities of the upper pressure tank and the lower pressure tank is 0.5 to 5 minutes;

[0048] The pressure regulating, filling, pressurizing and solidifying device adopts a vacuum pump group combined with a rotary vane vacuum pump + vacuum butterfly valve, is equipped with a filter, and the ultimate vacuum degree reaches -100 KPa (cold state of the empty furnace); for the upper pressure tank, synchronous gas charging, pressure difference building and exhaust after work all adopt a digital valve group system, and an exhaust and air supplementing system is provided. The pressurizing system adopts a dual-system cooperation for pressure control to achieve speed tracking and precision tracking; the pressurizing system of the lower pressure tank also adopts a digital system for pressure control to achieve speed tracking and precision tracking; synchronous gas charging, low-pressure filling and exhaust after work adopt a digital valve group system, which has air supplementing and exhaust functions. The pressurizing system adopts a dual-system cooperation for pressure control to achieve speed tracking and precision tracking; the pressurizing system of the lower pressure tank also adopts a digital system for pressure control to achieve speed tracking and precision tracking; synchronous gas charging, low-pressure filling and exhaust after work adopt a digital valve group system, which has air supplementing and exhaust functions. The pressurizing system adopts a dual-system cooperation for pressure control to achieve speed tracking and precision tracking;

[0049] Gas protection ensures that the gas flow of 2 paths can be digitally set, and the gas flow of other circuits can be manually set. Then they enter the gas mixing system at the same time, and the mixed gas is stored in the gas storage tank; at least 4 gas interfaces are provided, and different gases can be designed with different flows; the mixed gas has a pressurizing function, and the pressure after pressurization can be set; at least a 2-cubic mixed protective gas cylinder is configured; at least a 0.3-cubic melting protective gas storage tank is configured; the system has dual functions of pouring protective gas mixing and melting protective gas mixing; the pouring protective gas has a self-circulation stirring function after being stored for a certain time to prevent the settlement of gas components with high density. There is a monitoring and alarm function for the gas sources used in each circuit and the air pressure of the gas storage tank;

[0050] Fourthly, a cold drying and filtering system is also configured in the pressure regulating, filling, pressurizing and solidifying device, and the cold drying and filtering system adopts three-stage filtering;

[0051] The temperature control accuracy of the electric control system is ±5°C, and it has a timing heating control function and can automatically turn on heating according to the setting;

[0052] The control part of the electric control system adopts PLC + industrial computer control, and the control part includes a combination of the following functional units: electric furnace working control unit, pressurizing control unit, gas control unit, and lifting mechanism control unit.

[0053] In the pressure regulating, mold filling and pressure solidifying device, the control system adopts the IEC standard, selects electrical components and measuring components, and is simple and intuitive to operate. It has a protection and alarm system. It adopts the combined control mode of Siemens PLC + Siemens industrial computer; the locking adopts the hydraulic method, and the opening and closing of the hydraulic valve are controlled by the PLC of the main machine; the temperature control of the electric furnace adopts the temperature controller + thyristor power regulation + transformer control, and the maximum output power is 90kW. The temperature controller and the upper computer system communicate through the current signal to realize the full recording of temperature setting and acquisition; the pressure control system realizes double-layer control of pressure boosting for mold filling and solidification. The mold filling process adopts the set process tracking curve control, and the solidification pressure boosting control adopts the independent combined control of the upper and lower tanks. The differential pressure is jointly controlled, and the respective pressure curves that need to boost pressure after mold filling for the upper and lower tanks are independently controlled.

[0054] The system is set with a full-automatic production mode. When the process is mature, the process parameters can be set and stored to realize the automatic control of different processes for different workpieces; the full recording of data and the actual production process is realized for product quality control and cause tracing; the system has a shutdown recording function, which prompts the user to do the preparatory work before use according to the shutdown time, especially baking the furnace and detecting the airtightness. It can only be used after the user confirms that the preparatory work is done, which greatly ensures the user's use safety.

[0055] The pressure regulating, mold filling and pressure solidifying device is an aluminum liquid mold filling and pressure solidifying device, which has the following 4 groups of feedback signal contact functions: bottom of the mold, intermediate liquid level, top of the mold;

[0056] The bracket also includes: a gantry frame and sliding wheels; the bottom sliding wheels are arranged at the bottom of the gantry frame.

[0057] The present invention integrates a pressure tank, a lifting mechanism, an electric furnace, a pneumatic control system, an electric control system, and a bracket. This device supports two control modes: single-tank and double-tank. In the double-tank mode (the upper pressure tank and the lower pressure tank of the pressure tank), the upper pressure tank and the lower pressure tank of the pressure tank can independently perform operations such as pressurization, exhaust, and vacuum pumping, and can realize functions such as synchronous vacuum filling and rapid pressurization and solidification of the upper and lower pressure tanks of the pressure tank, and independent vacuum filling and rapid pressurization and solidification of the upper tank. The mold and the alloy liquid are respectively placed in the upper pressure tank and the lower pressure tank of the pressure tank. In the initial state, the pressures of the upper pressure tank and the lower pressure tank of the pressure tank are balanced, and both are in a vacuum / negative pressure / atmospheric pressure state. During the casting process of the casting, differential pressure is formed by means of air intake in the lower pressure tank of the pressure tank or air extraction in the upper pressure tank of the pressure tank according to the process plan, and real-time adjustment is carried out according to the preset process route to ensure smooth filling of the alloy liquid in the cavity. During the solidification stage of the casting, the pressures of the upper pressure tank and the lower pressure tank of the pressure tank will be precisely adjusted according to the process requirements to ensure the smooth solidification of the alloy liquid under pressure. This device and its method significantly improve the filling ability of the alloy, successfully realize the filling of large-plane thin-wall complex structures, effectively enhance the exhaust of the core, thereby greatly reducing the porosity defects of the casting and solving the problem of backfire. At the same time, the pressurized solidification technology further improves the density of the alloy structure, effectively reduces the shrinkage porosity defects of the casting, and significantly improves the mechanical properties of the casting. In addition, this device and method can also meet the process requirements of low-pressure casting, differential pressure casting, and pressure-regulating casting.

[0058] The beneficial effects of the present invention are reflected in that the alloy is prepared in a controllable environment, reducing the contact between the alloy liquid and the atmosphere, reducing the oxidation inclusions in the alloy, ensuring the purity of the alloy. During the casting process of the casting, the mold and the alloy liquid are respectively placed in the upper and lower pressure tanks, namely the upper pressure tank and the lower pressure tank of the pressure tank. The environmental pressure in the pressure tank can be adjusted in real time according to the established process route, eliminating the influence of the environmental pressure on the flow of the alloy liquid to the greatest extent, ensuring smooth filling of the alloy liquid in the cavity. During the solidification stage of the casting, the environmental pressure of the upper tank is adjusted in real time according to the process requirements to ensure the solidification of the alloy liquid under pressure and improve the metallurgical quality and density of the casting. Description of the Drawings

[0059] Figure 1 Schematic diagram of the position of the pressure-regulating filling and pressurized solidification device in Embodiment 1;

[0060] Figure 2 Front view of the upper pressure tank diagram;

[0061] Figure 3 Left view of the upper pressure tank diagram;

[0062] Figure 4 Top view of the upper pressure tank diagram;

[0063] Figure 5 Stereo reference diagram of the upper pressure tank diagram;

[0064] Figure 6 It is the front view of the middle partition diagram;

[0065] Figure 7 It is the top view of the middle partition diagram;

[0066] Figure 8 It is the schematic diagram of the overall structure of the electric furnace;

[0067] Figure 9 It is the sectional view of the electric furnace;

[0068] Figure 10 It is the schematic diagram of the lifting mechanism structure;

[0069] Figure 11 It is the stress distribution diagram of the pressure tank;

[0070] Figure 12 It is the deformation amount distribution diagram of the pressure tank;

[0071] The meanings of the reference numerals are as follows: pressure tank 1, upper pressure tank 1.1 of the pressure tank, lower pressure tank 1.2 of the pressure tank, middle partition 1.3;

[0072] Lifting mechanism 2, electric furnace 3, smelting electric furnace 3.1, crucible 3.2, riser pipe 3.3, furnace shell 3.4, sealing groove 3.5; pneumatic control system 4, electric control system 5, support 6, gantry frame 6.1, sliding wheel 6.2;

[0073] Figure 3 The protruding structures on the left and right sides in the middle are the hoisting and positioning structures. Specific embodiments

[0074] The present invention will be further described below in conjunction with the embodiments and the accompanying drawings of the specification, but not limited thereto.

[0075] Embodiment 1

[0076] A pressure regulating, filling and pressurizing solidification method uses a special pressure regulating, filling and pressurizing solidification device. The pressure regulating, filling and pressurizing solidification device includes a pressure tank 1, a lifting mechanism 2, an electric furnace 3, a pneumatic control system 4, an electric control system 5, and a support 6; wherein: the pressure tank 1 is further divided into two parts: the upper pressure tank 1.1 of the pressure tank, the lower pressure tank 1.2 of the pressure tank, and the middle partition 1.3; the electric furnace 3 is located in the lower pressure tank 1.2 of the pressure tank, and the upper pressure tank 1.1 and the lower pressure tank 1.2 of the pressure tank are fixedly connected into one body through the middle partition 1.3; the upper pressure tank 1.1 of the pressure tank is arranged above the middle partition 1.3; the middle partition 1.3 is arranged above the lower pressure tank 1.2 of the pressure tank; the upper pressure tank 1.1 of the pressure tank, the lower pressure tank 1.2 of the pressure tank, and the middle partition 1.3 are connected into a complete pressure vessel, the sealing ring adopts an O-shaped fluororubber sealing ring, and the locking structure adopts a wedge-shaped lock to ensure airtightness; the structure of the pressure tank 1 adopts a vertical structure; and its pressure-bearing range is 0.5 - 2 MPa;

[0077] The upper tank 1.1, middle partition 1.3, and lower tank 1.2 of the pressure tank are arranged in the internal space of the bracket 6 with a frame structure; the upper tank 1.1 of the pressure tank is arranged on the bracket 6 through the lifting mechanism 2; the lifting mechanism 2 has a hoisting unit and a translation unit; the lifting mechanism 2 is a gantry lifting and translating vehicle + hydraulic system; the lifting mechanism 2 includes a hydraulic lifting mechanism or / and a motor drive mechanism, and its motor control can achieve precise positioning of the tank combination; it has the functions of hoisting and translating the upper tank 1.1, middle partition 1.3 of the pressure tank, and low-pressure gaskets; the lifting of the upper tank 1.1 and middle partition 1.3 of the pressure tank adopts hydraulic lifting; the translation has multi-stage speed control to achieve precise positioning of the tank combination; it has multiple protection functions against falling, such as synchronization, back pressure, anti-retreat, and electricity.

[0078] The pneumatic control system 4 is connected to the upper tank 1.1 and lower tank 1.2 of the pressure tank 1; the electric control system 5 is respectively connected to the pressure tank 1, lifting mechanism 2, electric furnace 3, pneumatic control system 4, and bracket 6;

[0079] The electric furnace 3 is used to melt the alloy liquid. The electric furnace 3 includes: a melting electric furnace 3.1, a crucible 3.2, a riser pipe 3.3, a furnace shell 3.4, and a sealing groove 3.5; the electric furnace 3 is heated by a three-phase power supply, the heating element is a heating resistance belt, the furnace wire is selected as a high-temperature heating belt, and the furnace chamber in the furnace shell 3.4 is an integrated ceramic fiber furnace chamber; the electric furnace 3 for melting aluminum liquid has a safety operation protection frame to protect the safety of operators. The electric furnace 3 is internally provided with temperature measurement points and has the function of measuring the temperature of the alloy melt during the melting and vacuum casting processes. The inlet and exhaust pipe ports of the pneumatic control system 4 are located between the tank body of the pressure tank 1 and the furnace body of the electric furnace 3, and the furnace shell 3.4 of the electric furnace 3 is separately manufactured from the tank body of the pressure tank 1;

[0080] The upper tank 1.1 of the pressure tank is hoisted and transported by the lifting mechanism 2. Before pouring, it is hoisted by the lifting mechanism 2 directly above the electric furnace 3 and lowered onto the sand mold; the sand mold is placed above the middle partition 1.3 inside the upper tank 1.1 of the pressure tank.

[0081] In the pressure regulating, filling, pressurizing, and solidifying device, the electric furnace 3 is installed in the lower tank 1.2 of the pressure tank and is flush with the ground; the maximum heating temperature of the electric furnace 3 is 1000 - 1500 °C, the temperature uniformity is ≤ ±10 °C, and the heating power is: 50 - 80 kW;

[0082] The electric furnace 3 is internally provided with temperature measurement points, and the surface temperature of the furnace shell is ≤ the ambient temperature + 30 °C;

[0083] The inlet and exhaust pipe ports in the pneumatic control system 4 are located between the tank body and the furnace body, and the furnace body is separated from the tank body.

[0084] The pressure control accuracy of the pneumatic control system 4 during the alloy filling stage is ≤ ±5 KPa. The maximum liquid-lifting speed during the alloy filling stage is 20 - 200 mm / s in terms of aluminum. The pressure control accuracy during the holding pressure stage is ≤ ±1 KPa. The holding pressure time for the casting crystallization and solidification is 0 - 60 min. During the solidification pressurization process, the pressure increase speed is ≥ 100 KPa / min. The deviation between the "pressure difference - time" curve and the set curve is ≤ ±5 KPa.

[0085] Under the condition of an empty furnace in the cold state, the internal vacuum degree requirements for the upper tank 1.1 and the lower tank 1.2 of the pressure tank are 0.1 Pa - 20 KPa; under the working condition, it can maintain the internal vacuum degree of the upper and lower tanks to reach 0.1 KPa - 50 KPa (absolute vacuum degree). The vacuum pumping and pressure building time for the inner cavities of the upper tank 1.1 and the lower tank 1.2 of the pressure tank is 0.5 - 5 min;

[0086] The pressure regulating, filling, pressurizing and solidifying device adopts a vacuum pump group combined with a rotary vane vacuum pump + vacuum butterfly valve, and is equipped with a filter, and the ultimate vacuum degree reaches -100 KPa (empty furnace in the cold state); for the upper tank 1.1 of the pressure tank, the synchronous gas filling, pressure difference building and exhaust after work all adopt a digital valve group system, which ensures fast synchronous gas filling speed, accurate pressure difference building, and no pollution to the controller circuit during exhaust after work, etc., and is equipped with an exhaust and air supplement system. The pressurizing system adopts a dual-system cooperation for pressure control to achieve speed tracking and accuracy tracking; the pressurizing system of the lower tank 1.2 of the pressure tank also adopts a digital system for pressure control to achieve speed tracking and accuracy tracking; the synchronous gas filling, low-pressure filling and exhaust after work adopt a digital valve group system, which is equipped with air supplement and exhaust functions, and the pressurizing system adopts a dual-system cooperation for pressure control to achieve speed tracking and accuracy tracking;

[0087] Gas protection ensures that the gas flow of 2 paths can be digitally set, and the gas flow of other circuits can be manually set. At the same time, they enter the gas mixing system, and the mixed gas is stored in the gas storage tank; at least 4 gas interfaces are provided, and different gases can be designed with different flow rates; the mixed gas has a pressurization function, and the pressure after pressurization can be set; at least a 2-cubic gas storage tank for the mixed protective gas is configured; at least a 0.3-cubic melting protective gas storage tank is configured; the system has dual functions of gas mixing for pouring protection gas and gas mixing for melting protection; the pouring protection gas has a self-circulation stirring function after being stored for a certain time to prevent the settlement of gas components with high density. There is a monitoring and alarm function for the gas sources used in each circuit and the air pressure in the gas storage tank.

[0088] The pressure regulating, filling, pressurizing and solidifying device is also equipped with a cold drying and filtering system, and the cold drying and filtering system adopts three-stage filtering;

[0089] The temperature control accuracy of the electric control system 5 is ±5 °C, and it has a timing heating control function and can automatically turn on the heating according to the setting;

[0090] The control part of the electric control system 5 adopts PLC + industrial computer control, and the control part includes a combination of the following functional units: electric furnace working control unit, pressurization control unit, gas control unit, and lifting mechanism control unit.

[0091] In the pressure regulating filling pressurization solidification device, the control system adopts IEC standards, selects electrical components and measuring components, and is simple and intuitive to operate. It has a protection and alarm system. It adopts the combined control mode of Siemens PLC + Siemens industrial computer; the locking adopts a hydraulic method, and the opening and closing of the hydraulic valve are controlled by the PLC of the main machine; the temperature control of the electric furnace adopts a temperature controller + thyristor power regulation + transformer control, and the maximum output power is 90kW. The temperature controller and the upper computer system communicate through current signals to realize full recording of temperature setting and acquisition; the pressure control system realizes double-layer control of boosting for filling and solidification. The filling process adopts the control of setting process tracking curve, and the solidification boosting control adopts the independent combined control of the upper and lower tanks. The combined control differential pressure is used to independently control the respective pressure curves of the upper and lower tanks that need to be boosted after filling.

[0092] The system is set with a full-automatic production mode. When the process is mature, the process parameters can be set and stored to realize automatic control of different processes for different workpieces; it realizes full recording of data and the actual production process for product quality control and cause tracing; the system has a shutdown recording function, which prompts the user to do the preparatory work before use according to the shutdown time, especially baking the furnace and detecting airtightness. It can only be used after the user confirms that the preparatory work is done, which greatly ensures the user's use safety.

[0093] The pressure regulating filling pressurization solidification device is an aluminum liquid filling pressurization solidification device, which has the following 4 groups of feedback signal contact functions: bottom of the mold, middle liquid level, top of the mold; the bracket 6 includes: gantry frame 6.1, sliding wheel 6.2; the bottom sliding wheel 6.2 is arranged at the bottom of the gantry frame 6.1.

[0094] The pressure regulating filling pressurization solidification method using the aforementioned pressure regulating filling pressurization solidification device can be applied to the field of low-pressure casting. In the process of its implementation in the field of low-pressure casting, it successively includes the following steps and contents:

[0095] Step 1, low-pressure filling: The lower tank 1.2 of the pressure tank intakes air, adjusts the pressure, and the alloy liquid enters the mold cavity at a set speed and fills the mold cavity.

[0096] Step 2, shell building and pressurization: The lower tank 1.2 of the pressure tank continues to intake air, adjusts the air pressure, and changes according to the set shell building and pressurization pressure and shell building and pressurization time to complete shell building and pressurization.

[0097] Step 3, crystallization pressurization: The lower tank 1.2 of the pressure tank continues to intake air, adjusts the air pressure, and changes according to the crystallization pressurization pressure and shell building and pressurization time until crystallization pressurization is completed.

[0098] Step 4, holding pressure for solidification: Hold pressure for a set time until the casting solidifies under pressure;

[0099] Step 5, pressure relief: After the holding pressure ends, the lower tank 1.2 of the pressure tank is depressurized to atmospheric pressure, and the mold is taken out.

[0100] Example 2

[0101] The pressure regulating, filling, pressurizing and solidifying method using the pressure regulating, filling, pressurizing and solidifying device described in Example 1 is applied to the differential pressure casting process, and its specific process sequentially includes the following steps and contents:

[0102] Step 1, overall pressurization: The upper tank 1.1 and the lower tank 1.2 of the pressure tank are simultaneously filled with gas and pressurized synchronously;

[0103] Step 2, filling: Select the mode of the lower tank 1.2 of the pressure tank filling with gas or the upper tank 1.1 of the pressure tank relieving pressure, so that a pressure difference is formed between the upper tank 1.1 and the lower tank 1.2 of the pressure tank, and the alloy liquid enters the cavity at a set speed and fills the cavity;

[0104] Step 3, shell forming and pressurization: Select the mode of the lower tank 1.2 of the pressure tank continuing to fill with gas or the upper tank 1.1 of the pressure tank continuing to relieve pressure, adjust the air pressure, and change according to the shell forming and pressurization pressure and the shell forming and pressurization time until the shell forming and pressurization is completed;

[0105] Step 4, crystallization pressurization: The lower tank 1.2 of the pressure tank continues to fill with gas or the upper tank 1.1 of the pressure tank continues to relieve pressure, adjust the air pressure, and change according to the crystallization pressurization pressure and the shell forming and pressurization time until the crystallization pressurization is completed;

[0106] Step 5, holding pressure for solidification: Hold pressure for a set time until the casting solidifies under a higher pressure;

[0107] Step 6, pressure relief: After the holding pressure ends, the upper tank 1.1 and the lower tank 1.2 of the pressure tank are simultaneously exhausted and depressurized to atmospheric pressure, and the mold is taken out.

[0108] Example 3

[0109] The pressure regulating, filling, pressurizing and solidifying method using the pressure regulating, filling, pressurizing and solidifying device described in Example 1 is applied to the process of pressurizing and solidifying after vacuum filling;

[0110] In the process of pressurizing and solidifying after vacuum filling the upper tank 1.1 and the lower tank 1.2 of the pressure tank, the specific process sequentially includes the following steps and contents:

[0111] Step 1, overall vacuum pumping: The upper tank 1.1 and the lower tank 1.2 of the pressure tank are vacuum pumped synchronously;

[0112] Step 2, overall vacuum filling: The lower tank 1.2 of the pressure tank intakes air separately, adjusts the vacuum degree, so that a pressure difference is formed between the upper tank 1.1 and the lower tank 1.2 of the pressure tank, and the alloy liquid enters the cavity at a set speed and fills the cavity;

[0113] Step 3, shell building and pressure boosting: The lower tank 1.2 of the pressure tank intakes air, adjusts the air pressure, and changes according to the shell building and pressure boosting pressure and the shell building and pressure boosting time until the shell building and pressure boosting are completed;

[0114] Step 4, overall pressure boosting: The upper tank 1.1 and the lower tank 1.2 of the pressure tank intake air simultaneously, so that the upper tank 1.1 and the lower tank 1.2 of the pressure tank are synchronously boosted to the set pressure;

[0115] Step 5, crystallization pressure boosting: The lower tank 1.2 of the pressure tank continues to intake air, adjusts the air pressure, and changes according to the crystallization pressure boosting and the shell building and pressure boosting time until the crystallization pressure boosting is completed;

[0116] Step 6, pressure holding and solidification: Pressure is held for a set time until the casting solidifies under a higher pressure;

[0117] Step 7, pressure relief: After the pressure holding ends, the upper tank 1.1 and the lower tank 1.2 of the pressure tank exhaust air simultaneously to relieve pressure to atmospheric pressure, and the mold is taken out.

[0118] Example 4

[0119] The pressure regulating, filling, pressurizing and solidifying method using the pressure regulating, filling, pressurizing and solidifying device described in Example 1 is applied to the process of pressure regulating, filling, pressurizing and solidifying after vacuum filling of the upper tank 1.1 of the pressure tank. The specific process sequentially includes the following steps and contents:

[0120] Step 1, vacuum filling of the upper tank 1.1 of the pressure tank: The lower tank 1.2 of the pressure tank maintains atmospheric pressure, and the upper tank 1.1 of the pressure tank is separately evacuated to form a pressure difference between the upper tank 1.1 and the lower tank 1.2 of the pressure tank. The alloy liquid is sucked into the cavity at a set speed until the alloy fills the mold and the filling is completed;

[0121] Step 2, shell building and pressure boosting: The upper tank 1.1 of the pressure tank continues to intake air, adjusts the air pressure, and changes according to the shell building and pressure boosting pressure and the shell building and pressure boosting time to complete the shell building and pressure boosting;

[0122] Step 3, overall pressure boosting: The upper tank 1.1 and the lower tank 1.2 of the pressure tank intake air simultaneously, so that the upper tank 1.1 and the lower tank 1.2 of the pressure tank are synchronously boosted to the set pressure;

[0123] Step 4, crystallization pressure boosting: The upper tank 1.1 of the pressure tank continues to intake air, adjusts the air pressure, and changes according to the crystallization pressure boosting and the shell building and pressure boosting time until the crystallization pressure boosting is completed;

[0124] Step 5, pressure holding and solidification: Pressure is held for a set time until the casting solidifies under a higher pressure;

[0125] Step 6, pressure relief: After the pressure holding is completed, the upper tank 1.1 and the lower tank 1.2 of the pressure tank exhaust air and relieve pressure simultaneously until the normal pressure is reached, and then take out the mold.

[0126] Example 5

[0127] This example is the low-pressure casting process of a certain aviation-class main engine casing. The specific process is as follows:

[0128] (1) Low-pressure filling: The upper tank 1.1 of the pressure tank is not required; the lower tank 1.2 of the pressure tank intakes air alone, adjusts the pressure of the lower tank 1.2 of the pressure tank, and makes the alloy liquid enter the mold cavity from the melting furnace at a set speed of 75 mm / s until the alloy fills the mold and the filling is completed;

[0129] (2) Crust-forming pressure increase: The lower tank 1.2 of the pressure tank continues to intake air, adjusts the air pressure alone, sets the crust-forming pressure increase to 3 KPa and the crust-forming pressure increase time to 30 S, and completes the crust-forming pressure increase;

[0130] (3) Crystallization pressure increase: The lower tank 1.2 of the pressure tank continues to intake air, adjusts the air pressure alone, and the crystallization pressure increase is 5 KPa until the crystallization pressure increase is completed;

[0131] (4) Pressure holding and solidification: Hold the pressure for a set time of 600 S until the casting solidifies under pressure;

[0132] (5) Pressure relief: After the pressure holding is completed, the lower tank 1.2 of the pressure tank exhausts air and relieves pressure until the normal pressure is reached, and then takes out the mold.

[0133] Example 6

[0134] This example is the differential pressure casting process of a certain aluminum alloy shell. The specific process is as follows:

[0135] (1) Overall pressure increase: The upper tank 1.1 and the lower tank 1.2 of the pressure tank intake air simultaneously, so that the upper and lower tanks of the upper tank 1.1 and the lower tank 1.2 of the pressure tank are synchronously pressurized to 700 KPa. During the pressure increase process, it is necessary to ensure that the pressure difference is basically constant (deviation ≤ ±2 KPa) to avoid too large an up-and-down fluctuation amplitude of the alloy liquid in the riser tube in the furnace;

[0136] (2) Filling: The operator independently selects the air intake mode of the lower tank 1.2 of the pressure tank, so that a pressure difference △P = 30 KPa is formed between the upper tank 1.1 and the lower tank 1.2 of the pressure tank, and the alloy liquid enters the mold cavity from the melting furnace at a set speed of 30 mm / s until the alloy fills the mold and the filling is completed. During the filling process, △P between the upper tank 1.1 and the lower tank 1.2 of the pressure tank ≤ ±0.5 KPa;

[0137] (3) Crust pressurization: The lower tank 1.2 of the pressure tank continues to intake air, and the air pressure is adjusted so that the pressure difference between the upper tank 1.1 and the lower tank 1.2 of the pressure tank is 2 KPa for crust formation. The crust pressurization time is 10 s, and the pressure rising speed during the pressurization process is 1 KPa / s. The control accuracy of △P between the upper tank 1.1 and the lower tank 1.2 of the pressure tank is ≤ ±0.5 KPa until the crust pressurization is completed;

[0138] (4) Crystallization pressurization: The lower tank 1.2 of the pressure tank continues to intake air, and the air pressure is adjusted so that the pressure difference between the upper tank 1.1 and the lower tank 1.2 of the pressure tank is 15 KPa for crystallization pressurization. The pressure rising speed during the pressurization process is 1 KPa / s. The control accuracy of △P between the upper tank 1.1 and the lower tank 1.2 of the pressure tank is ≤ ±0.5 KPa until the crystallization pressurization is completed;

[0139] (5) Pressure holding and solidification: Pressure is held for the set time of 540 s until the casting solidifies under a relatively high pressure;

[0140] (6) Pressure relief: After the pressure holding ends, the upper tank 1.1 and the lower tank 1.2 of the pressure tank exhaust air and relieve pressure simultaneously to atmospheric pressure. The upper tank 1.1 of the pressure tank is opened, and the mold is taken out.

[0141] Example 7

[0142] This example is the pressurized solidification process after vacuum pumping and filling of the upper and lower tanks of a thin-walled and complex aluminum alloy casing. The specific process is as follows:

[0143] (1) Overall vacuum pumping: The upper tank 1.1 and the lower tank 1.2 of the pressure tank are vacuum pumped synchronously to reach the working vacuum degree P0 ≤ -80 KPa;

[0144] (2) Overall vacuum filling: The lower tank 1.2 of the pressure tank intakes air alone, and the vacuum degree of the lower tank is adjusted so that a pressure difference of 50 KPa is formed between the upper tank 1.1 and the lower tank 1.2 of the pressure tank. The alloy liquid enters the mold cavity from the melting furnace at the set speed of 50 mm / s until the alloy fills the mold to complete the filling. The control accuracy of △P between the upper tank 1.1 and the lower tank 1.2 of the pressure tank during the filling process is ≤ ±0.5 KPa;

[0145] (3) Crust pressurization: The lower tank 1.2 of the pressure tank intakes air, and the air pressure is adjusted alone so that the pressure difference △P between the upper tank 1.1 and the lower tank 1.2 of the pressure tank changes according to the crust pressurization pressure of 2 KPa and the crust pressurization time of 5 s. The pressure rising speed during the pressurization process is 1 KPa / s. The control accuracy of △P between the upper tank 1.1 and the lower tank 1.2 of the pressure tank is ≤ ±0.5 KPa until the crust pressurization is completed;

[0146] (4) Overall pressurization: The upper tank 1.1 and the lower tank 1.2 of the pressure tank are simultaneously filled with gas, so that the two tanks of the upper tank 1.1 and the lower tank 1.2 of the pressure tank are synchronously pressurized from negative pressure to above 600 KPa within 70 s. During the pressurization process, it is necessary to ensure that the pressure difference is basically constant (deviation ≤ ±2 KPa) to avoid large fluctuations of the molten alloy up and down in the mold cavity;

[0147] (5) Crystallization pressurization: The lower tank 1.2 of the pressure tank continues to be filled with gas, and the air pressure is adjusted separately, so that the pressure difference △P between the upper tank 1.1 and the lower tank 1.2 of the pressure tank changes according to the crystallization pressurization pressure of 5 KPa. The pressure rising speed during the pressurization process is 1 KPa / s, and the control accuracy of the pressure difference △P between the upper tank 1.1 and the lower tank 1.2 of the pressure tank is ≤ ±0.5 KPa until the crystallization pressurization is completed;

[0148] (6) Pressure holding and solidification: Pressure holding is carried out according to the set time of 600 s until the casting solidifies under a higher pressure;

[0149] (7) Pressure relief: After the pressure holding is completed, the upper tank 1.1 and the lower tank 1.2 of the pressure tank are simultaneously exhausted to atmospheric pressure, and the upper tank 1.1 of the pressure tank is opened to take out the mold.

[0150] Example 8

[0151] This example is the process of pressurized solidification after vacuum filling of the upper tank of a thin-walled and complex magnesium alloy casing casting.

[0152] The specific process is as follows:

[0153] (1) Vacuum filling of the upper tank: The lower tank 1.2 of the pressure tank maintains atmospheric pressure, and the upper tank is separately evacuated to form a pressure difference between the upper tank 1.1 and the lower tank 1.2 of the pressure tank. The molten alloy is sucked into the mold cavity from the melting furnace at a set speed of 50 mm / s until the alloy fills the mold and the filling is completed;

[0154] (2) Crust forming pressurization: The lower tank 1.2 of the pressure tank continues to be filled with gas, and the air pressure is adjusted separately. The crust forming pressurization pressure is 2 KPa and the crust forming pressurization time is 5 s to complete the crust forming pressurization;

[0155] (3) Overall pressurization: The upper tank 1.1 and the lower tank 1.2 of the pressure tank are simultaneously filled with gas, so that the two tanks of the upper tank 1.1 and the lower tank 1.2 of the pressure tank are synchronously pressurized from negative pressure to above 600 KPa within 60 s. During the pressurization process, it is necessary to ensure that the pressure difference is basically constant to avoid large fluctuations of the molten alloy up and down in the mold cavity;

[0156] (4) Crystallization pressurization: The lower tank 1.2 of the pressure tank continues to be filled with gas, and the air pressure is adjusted separately. The crystallization pressurization pressure is 5 KPa until the crystallization pressurization is completed;

[0157] (5) Pressure holding and solidification: Pressure is held for 600 s as set until the casting solidifies under a relatively high pressure;

[0158] (6) Pressure relief: After the pressure holding ends, the upper tank 1.1 and the lower tank 1.2 of the pressure tank exhaust and relieve pressure simultaneously until normal pressure is reached. Then, the upper tank 1.1 of the pressure tank is opened and the mold is taken out.

Claims

1. A pressure-regulated filling and pressurized solidification method using a pressure-regulated filling and pressurized solidification device, characterized in that: The pressure-regulated filling and pressurized solidification method uses a special pressure-regulated filling and pressurized solidification device; the pressure-regulated filling and pressurized solidification device comprises a pressure tank (1), a lifting mechanism (2), an electric furnace (3), a gas control system (4), an electric control system (5), and a bracket (6); wherein: the pressure tank (1) is further divided into two parts: an upper pressure tank (1.1), a lower pressure tank (1.2), and a middle partition (1.3); the electric furnace (3) is located in the lower pressure tank (1.2), and the upper pressure tank (1.1) and the lower pressure tank (1.2) are The pressure tank (1) is fixedly connected as a whole through a middle diaphragm (1.3); the upper tank (1.1) of the pressure tank is arranged above the middle diaphragm (1.3); the middle diaphragm (1.3) is arranged above the lower tank (1.2) of the pressure tank; the upper tank (1.1) of the pressure tank, the lower tank (1.2) of the pressure tank and the middle diaphragm (1.3) are connected to form a complete pressure vessel, the sealing ring adopts an O-type fluororubber sealing ring, and the locking structure adopts a wedge-shaped locking to ensure air tightness; the pressure tank (1) adopts a vertical structure; and its pressure range is 0.5 to 2MPa; The upper tank (1.1) of the pressure tank, the middle partition (1.3) and the lower tank (1.2) of the pressure tank are arranged in the internal space of the frame-type structure bracket (6); the upper tank (1.1) of the pressure tank is arranged on the bracket (6) through a lifting mechanism (2); the lifting mechanism (2) has a hoisting unit and a translation unit; the lifting mechanism (2) is a gantry lifting and translation vehicle + hydraulic system; the lifting mechanism (2) includes a hydraulic lifting mechanism and / or a motor driving mechanism, which can realize accurate positioning of the tank by using motor control; it has the function of lifting and translating the upper tank (1.1) of the pressure tank, the middle partition (1.3) and the low-pressure gasket; the lifting of the upper tank (1.1) of the pressure tank and the middle partition (1.3) is hydraulic lifting; the translation has multi-stage speed control to realize accurate positioning of the tank; The gas control system (4) is connected to the upper pressure tank (1.1) and the lower pressure tank (1.2) in the pressure tank (1); the electric control system (5) is respectively connected to the pressure tank (1), the lifting mechanism (2), the electric furnace (3), the gas control system (4), and the bracket (6); The electric furnace (3) is used to melt the alloy liquid. The electric furnace (3) comprises: a smelting electric furnace (3.1), a crucible (3.2), a liquid riser (3.3), a furnace shell (3.4), and a sealing groove (3.5); the electric furnace (3) is heated by a three-phase power supply, the heating element is a heating resistor belt, the furnace wire is a high-temperature heating belt, and the furnace chamber in the furnace shell (3.4) is a ceramic fiber integrated furnace chamber; the electric furnace (3) has a built-in temperature measuring point; the inlet and outlet pipes of the gas control system (4) are located between the tank body of the pressure tank (1) and the furnace body of the electric furnace (3), and the furnace shell (3.4) of the electric furnace (3) is manufactured separately from the tank body of the pressure tank (1); The upper tank (1.1) of the pressure tank is hoisted and transported by the lifting mechanism (2). Before pouring, it is hoisted by the lifting mechanism (2) to the top of the electric furnace (3), and then dropped to the top of the sand mold; the sand mold is placed above the middle partition (1.3) inside the upper tank (1.1) of the pressure tank; The pressure-adjusting, filling and pressurizing solidification method can be applied to the field of low-pressure casting, and the method comprises the following steps and contents in sequence during its application in the field of low-pressure casting: Step 1, low-pressure filling: the lower tank of the pressure tank (1.2) is filled with air, the pressure is adjusted, and the alloy liquid enters the cavity at a set speed and fills the cavity; Step 2, crust pressurization: the lower tank of the pressure tank (1.2) continues to take in air, adjusts the air pressure, and completes crust pressurization according to the set crust pressurization pressure and crust pressurization time; Step 3, crystallization pressurization: the lower tank of the pressure tank (1.2) continues to take in air, and the air pressure is adjusted according to the crystallization pressurization pressure and crusting pressurization time until the crystallization pressurization is completed; Step 4, pressure holding and solidification: set the time to hold the pressure until the casting solidifies under pressure; Step 5, pressure relief: After the pressure maintenance is completed, the pressure in the lower tank (1.2) of the pressure tank is relieved to normal pressure, and the casting mold is taken out.

2. The pressure-adjusting, filling and pressurized solidification method according to claim 1, characterized in that: The pressure-adjusting, filling and pressurizing solidification method is applied to the differential pressure casting process, and the specific process includes the following steps and contents in sequence: Step 1, overall pressurization: the upper tank (1.1) and the lower tank (1.2) of the pressure tank are simultaneously fed with air and pressurized synchronously; Step 2, filling: select the air intake mode of the lower tank (1.2) of the pressure tank or the pressure relief mode of the upper tank (1.1) of the pressure tank, so that a pressure difference is formed between the upper tank (1.1) of the pressure tank and the lower tank (1.2) of the pressure tank, and the alloy liquid enters the mold cavity at a set speed and fills the mold cavity; Step 3, crust pressurization: select the lower tank of the pressure tank (1.2) to continue the air intake or the upper tank of the pressure tank (1.1) to continue the pressure relief mode, adjust the air pressure, and change the crust pressurization pressure and crust pressurization time until the crust pressurization is completed; Step 4, crystallization pressurization: the lower tank of the pressure tank (1.2) continues to take in air or the upper tank of the pressure tank (1.1) continues to release pressure, and the air pressure is adjusted according to the crystallization pressurization pressure and crusting pressurization time until the crystallization pressurization is completed; Step 5, pressure holding and solidification: set the time to hold the pressure until the casting solidifies under a higher pressure; Step 6, pressure relief: After the pressure maintenance is completed, the upper tank (1.1) and the lower tank (1.2) of the pressure tank are simultaneously vented and pressure-relieved to normal pressure, and the casting mold is taken out.

3. The pressure-adjusting, filling and pressurized solidification method according to claim 1, characterized in that: The pressure-adjusting filling and pressurized solidification method is applied to the vacuum filling and pressurized solidification process instead; The specific process of the pressure tank upper tank (1.1) and the pressure tank lower tank (1.2) vacuum filling and pressurizing solidification process includes the following steps and contents in sequence: Step 1, overall vacuuming: the upper tank (1.1) and the lower tank (1.2) of the pressure tank are vacuumed synchronously; Step 2, overall vacuum filling: the lower tank (1.2) of the pressure tank is independently air-intaken, and the vacuum degree is adjusted to form a pressure difference between the upper tank (1.1) of the pressure tank and the lower tank (1.2) of the pressure tank, and the alloy liquid enters the mold cavity at a set speed and fills the mold cavity; Step 3, crust pressurization: the lower tank (1.2) of the pressure tank is fed with air, and the air pressure is adjusted according to the crust pressurization pressure and crust pressurization time, until the crust pressurization is completed; Step 4, overall pressurization: the upper tank (1.1) and the lower tank (1.2) of the pressure tank are simultaneously fed with air, so that the upper tank (1.1) and the lower tank (1.2) of the pressure tank are pressurized to a set pressure synchronously; Step 5, crystallization pressurization: the lower tank of the pressure tank (1.2) continues to take in air, and the air pressure is adjusted according to the crystallization pressurization pressure and crusting pressurization time until the crystallization pressurization is completed; Step 6, pressure holding and solidification: set the time to hold the pressure until the casting solidifies under a higher pressure; Step 7, pressure relief: After the pressure maintenance is completed, the upper tank (1.1) and the lower tank (1.2) of the pressure tank are simultaneously vented and pressure-relieved to normal pressure, and the casting mold is taken out.

4. The pressure-adjusting, filling and pressurized solidification method according to claim 1, characterized in that: The pressure-adjusting, filling and pressurized solidification method is applied to the pressure tank upper tank (1.1) to replace the vacuum filling and pressurized solidification process, and the specific process includes the following steps and contents in sequence: Step 1, vacuum filling of the upper tank (1.1) of the pressure tank: the lower tank (1.2) of the pressure tank is maintained at normal pressure, and the upper tank (1.1) of the pressure tank is evacuated separately to form a pressure difference between the upper tank (1.1) of the pressure tank and the lower tank (1.2) of the pressure tank, and the alloy liquid is sucked into the mold cavity at a set speed until the alloy fills the casting mold, and the filling is completed; Step 2, crust pressurization: the pressure tank upper tank (1.1) continues to take in air, adjusts the air pressure, and completes crust pressurization according to the crust pressurization pressure and crust pressurization time changes; Step 3, overall pressurization: the upper tank (1.1) and the lower tank (1.2) of the pressure tank are simultaneously fed with air, so that the upper tank (1.1) and the lower tank (1.2) of the pressure tank are simultaneously pressurized to a set pressure; Step 4, crystallization pressurization: the pressure tank upper tank (1.1) continues to take in air, and the air pressure is adjusted according to the crystallization pressurization pressure and crusting pressurization time until the crystallization pressurization is completed; Step 5, pressure holding and solidification: set the time to hold the pressure until the casting solidifies under a higher pressure; Step 6, pressure relief: After the pressure maintenance is completed, the upper tank (1.1) and the lower tank (1.2) of the pressure tank are simultaneously vented and pressure-relieved to normal pressure, and the casting mold is taken out.

5. The pressure-adjusting, filling and pressurized solidification method according to claim 1, characterized in that: The pressure-adjusting, filling and pressurized solidification method meets one or a combination of the following requirements: First, the pressure-adjusting, filling and pressurized solidification device meets the following requirements: the electric furnace (3) is installed in the lower tank (1.2) of the pressure tank; the maximum heating temperature of the electric furnace (3) is 1000-1500°C, the temperature uniformity is ≤±10°C, and the heating power is 50-80kW; the electric furnace (3) has a built-in temperature measuring point, and the furnace shell surface temperature is ≤ambient temperature+30°C; the inlet and exhaust pipes in the gas control system (4) are located between the tank body and the furnace body, and the furnace body is separated from the tank body; Secondly, the pressure control accuracy of the gas control system (4) during the alloy filling stage is ≤±5KPa, the maximum liquid rising speed during the alloy filling stage is 20-200mm / s, the pressure holding control accuracy is ≤±1KPa, the casting crystallization solidification holding time is: 0-60min, during the solidification pressurization process, the pressure increase speed is ≥100KPa / min, and the deviation between the "pressure difference-time" curve and the set curve is ≤±5KPa; Third, under the cold condition of the empty furnace, the internal vacuum degree of the pressure tank upper tank (1.1) and the pressure tank lower tank (1.2) is required to be 0.1Pa~20KPa; under working conditions, the internal vacuum degree of the upper and lower tanks can be maintained at 0.1KPa~50KPa, and the vacuuming and pressure building time of the inner cavity of the pressure tank upper tank (1.1) and the pressure tank lower tank (1.2) is 0.5~5min; The pressure-regulating, filling and pressurized solidification device adopts a vacuum pump group composed of a rotary vane vacuum pump + a vacuum butterfly valve, and is equipped with a filter, and the ultimate vacuum degree reaches -100KPa; the synchronous inflation, pressure difference building and exhaust after work of the upper tank (1.1) of the pressure tank adopt a digital valve group system, and is provided with an exhaust and air supply system, and the pressurization system adopts a dual system to cooperate with the pressure control to achieve speed tracking and precision tracking; the pressurization system of the lower tank (1.2) of the pressure tank also adopts a digital system to cooperate with the pressure control to achieve speed tracking and precision tracking; the synchronous inflation, low-pressure filling and exhaust after work adopt a digital valve group system, which is provided with air supply and exhaust functions, and the pressurization system adopts a dual system to cooperate with the pressure control to achieve speed tracking and precision tracking; Gas protection, ensure that the flow of 2 gases can be set digitally, and the flow of other circuit gases can be set manually, and enter the gas mixing system at the same time, and the mixed gas is stored in the gas tank; provide at least 4 gas interfaces, different gases can be designed with different flow rates; the mixed gas has a pressurization function, and the pressure after pressurization can be set; configure at least 2 cubic meters of mixed protective gas tanks; configure at least 0.3 cubic meters of melting protective gas tanks; the system has the dual functions of pouring protective gas mixing and melting protective gas mixing; the pouring protective gas has a self-circulating stirring function after being stored for a certain period of time to prevent the sedimentation of high-density gas components. There are monitoring and alarm functions for the gas source used in each circuit and the gas tank pressure; Fourthly, the pressure-regulating, filling and pressurized solidification device is also equipped with a cold-dry filtration system, which adopts three-stage filtration; The temperature control accuracy of the electric control system (5) is ±5°C, and it has a timed heating control function and can automatically start heating according to the setting; The control part of the electric control system (5) is controlled by PLC+industrial computer, and the control part includes a combination of the following functional units: an electric furnace operation control unit, a pressurization control unit, a gas control unit, and a lifting mechanism control unit; In the pressure-regulated filling and pressurized solidification device, the control system adopts the IEC standard and adopts the joint control mode of Siemens PLC + Siemens industrial computer; the locking adopts hydraulic mode, and the opening and closing of the hydraulic valve is controlled by the PLC of the host; the temperature control of the electric furnace adopts temperature control meter + thyristor power regulation + transformer control, and the maximum output power is 90kW. The temperature control meter and the upper computer system communicate through current signals to realize full record of temperature setting collection; the pressure control system realizes double-layer control of boosting and filling and solidification. The filling process adopts the set process tracking curve control, and the solidification boost control adopts the independent joint control of the upper and lower tanks, and the pressure difference is jointly controlled to independently control the respective pressure curves of the upper tank and the lower tank that need to be boosted after filling.

6. The pressure-adjusting, filling and pressurized solidification method according to claim 5, characterized in that: The pressure-adjusting, mold-filling and pressurized solidification device is an aluminum liquid filling and pressurized solidification device, which has the following four groups of feedback signal contact functions: mold bottom, middle liquid level, mold top; The bracket (6) also includes: a gantry frame (6.1) and a sliding wheel (6.2); the bottom sliding wheel (6.2) is arranged at the bottom of the gantry frame (6.1).

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