Light alloy semi-solid melt preparation and injection extrusion casting forming equipment and method

Abstract

The invention belongs to the technical field of nonferrous metal material preparation, and discloses light alloy semi-solid melt preparation and injection extrusion casting forming equipment and method.The equipment comprises a melt microstructure intelligent prediction module, a melt preparation unit and an extrusion casting forming unit; the method comprises the steps of equipment preheating, semi-solid melt preparation, injection feeding and extrusion casting forming. Seamless butt joint of the melt preparation unit and the extrusion casting forming unit is achieved, and the integrated process from preparation to forming of the semi-solid melt is achieved; the optimal process parameters of the semi-solid melt preparation process are determined by coupling a unified phase field model to predict microstructure morphology changes under different process parameters in the semi-solid melt preparation process, and the melt preparation process is optimized. And the method is of great significance for improving the controllability of the semi-solid melt, the stability of the semi-solid formed casting and the product quality.

Description

Technical Field

[0001] The present invention belongs to the technical field of non-ferrous metal material preparation, and particularly relates to a device and method for preparing a semi-solid melt of a light alloy and injection extrusion casting forming. Background Art

[0002] As a new metal material forming process, the semi-solid extrusion casting forming technology has the following advantages compared with the traditional extrusion casting: high melt viscosity, easy to control filling; less gas entrapment during filling, reducing oxidation and improving mechanical properties; low deformation temperature and small thermal shock, long die life; easy to realize automation and improve processing efficiency, and has extremely wide application prospects in the fields of aerospace, transportation, communication, etc.

[0003] The semi-solid extrusion casting forming technology is mainly divided into two stages, namely the semi-solid melt preparation stage and the extrusion casting forming stage. However, the existing semi-solid extrusion casting forming processes at present have obvious disconnection in the melt preparation and forming stages. First, the metal raw materials are heated to prepare a semi-solid melt, and then the semi-solid melt is subjected to extrusion casting forming. The current extrusion casting forming processes generally include the rheological extrusion casting process and the thixoforming process. In the rheological extrusion casting process, the prepared semi-solid melt is transferred into the cylinder through a crucible or a ladle to complete filling and solidification, which inevitably causes problems such as oxidation and difficult temperature control during the transfer process of the melt; thixoforming can obtain the billet form of the cooled formed or large plastic deformed bulk alloy, which has the advantages of convenient transportation and storage and stable quality of the formed parts, but also has disadvantages such as cumbersome process, high energy consumption, and easy residual deformation structure in the microstructure. Summary of the Invention

[0004] The purpose of the present invention is to provide a device and method for preparing a semi-solid melt of a light alloy and injection extrusion casting forming in view of the situation of the background art.

[0005] In one aspect of the present invention, there is provided a device for preparing a semi-solid melt of a light alloy and injection extrusion casting forming, including an intelligent prediction module for the melt microstructure, a melt preparation unit, and an extrusion casting forming unit. The melt preparation unit is horizontally arranged and includes an injection oil cylinder, a piston rod, an oil cylinder fixing seat, a servo motor, a motor shaft, a motor fixing seat, a motor guide sleeve, a coaxiality adjusting device, a guide post, a feed port guide sleeve, a feed port fixing seat, a feed hopper, a stirring screw, a material pipe, an infrared heater, a material pipe thermocouple, and a nozzle; the extrusion casting forming unit is vertically arranged on the workbench and includes a fixed die frame, a fixed die core, a cylinder, a sprue bush, a sprue bush fixing plate, a pressure head, a pressure rod, a moving die frame, a moving die core, a flow splitting cone, a moving die electric heating plate, a fixed die electric heating plate, a cylinder heating sleeve, a mold temperature controller, and an ejection assembly, wherein: The intelligent prediction module for the melt microstructure is used to determine the process parameters for preparing the semi-solid melt by predicting the microstructure based on the unified phase field model. The process parameters for preparing the semi-solid melt include the melt temperature, stirring speed, and stirring time. The servo motor is installed on the motor fixing base. The motor shaft is connected to the stirring screw via the coaxiality adjusting device. The oil cylinder fixing base is arranged outside the motor fixing base. The injection oil cylinder is installed on the oil cylinder fixing base. The guide posts are fixed between the workbench and the oil cylinder fixing base. The motor guide sleeve is sleeved on the guide posts, and the motor fixing base is fixedly connected to the motor guide sleeve. The piston rod is connected to the motor fixing base. The material pipe is divided into three parts: the head of the material pipe, the middle of the material pipe, and the tail of the material pipe. The feeding port fixing base is arranged between the coaxiality adjusting device and the tail of the material pipe. The side of the feeding port fixing base is fixedly connected to the tail of the material pipe. The feeding funnel is arranged on the upper part of the feeding port fixing base. The feeding port guide sleeve is fixedly connected to the lower part of the feeding port fixing base. The feeding port guide sleeve is sleeved on the guide posts and fixed to the guide posts by fixing bolts. The feeding end of the stirring screw penetrates through the feeding port fixing base. The end of the stirring screw extending out of the feeding port fixing base is connected to the motor shaft. The feeding funnel arranged on the upper part of the feeding port fixing base is communicated with the feeding end of the stirring screw. The rest of the stirring screw is installed in the material pipe. The discharging end of the stirring screw is equipped with a support ring for supporting and installing the stirring screw, a screw head for pushing the material, and a check ring for preventing reverse backflow. The nozzle is connected to the head of the material pipe through a flange and bolts. The head of the material pipe, the middle of the material pipe, and the tail of the material pipe are respectively covered with an infrared heater and correspondingly equipped with a material pipe thermocouple. At the bottom of the squeeze casting forming unit, there are a fixed mold heat insulation plate and a fixed mold fixing plate fixed on the workbench by a pressing plate. The fixed mold frame is installed on the fixed mold fixing plate. The material cylinder is installed in the fixed mold frame. The injection head and the injection rod are installed in the material cylinder. The fixed mold core is fitted and installed at the top of the material cylinder. The outside of the material cylinder is covered with a material cylinder heating sleeve and correspondingly equipped with a material cylinder thermocouple. On one side of the material cylinder facing the nozzle, there is a gate. The gate sleeve is fitted and installed on the gate. The gate sleeve fixing plate is connected between the gate sleeve and the flange. The gate sleeve fixing plate is concentrically installed with the gate sleeve and internally communicated. The nozzle is inserted into the gate sleeve fixing plate and the gate sleeve, and the nozzle cavity of the nozzle is communicated with the gate. On one side of the fixed mold frame facing the nozzle, there is a flange backing plate for supporting and fixing the flange. The moving die frame is installed on the upper part of the fixed die frame, and the moving die frame and the fixed die frame are positioned and aligned with each other through guide rods and matching guide sleeves. The moving die core is installed in the moving die frame, and a flow splitting cone is connected to the moving die core. The moving die core and the fixed die core jointly form a mold cavity. The ejection assembly is arranged above the moving die frame and includes a push plate, a push plate fixing plate, ejector rods, and a reset rod. On both sides of the ejection assembly, mold feet are provided on the upper part of the moving die frame. The push plate and the push plate fixing plate are fitted and installed between the mold feet on both sides. The ejector rods and the reset rod are installed on the lower bottom surface of the push plate fixing plate, and the free ends of the ejector rods and the reset rod both pass through the moving die frame and the moving die core. The ejector rods are arranged to face the mold cavity, the reset rods are arranged to deviate from the mold cavity, and the length of the reset rods is greater than the length of the ejector rods; The outside of the moving die frame is covered with the moving die electric heating plate, and the outside of the fixed die frame is covered with the fixed die electric heating plate. Both the moving die frame and the fixed die frame are provided with oil channels, and the mold temperature controller is connected to the oil channels of the moving die frame and the fixed die frame via heating oil pipes.

[0006] Further, in the above-mentioned light alloy semi-solid melt preparation and injection extrusion casting forming equipment, the sprue bushing is covered with a heating device to heat and keep warm the transported melt.

[0007] Further, in the above-mentioned light alloy semi-solid melt preparation and injection extrusion casting forming equipment, a fixed die core groove is provided on the lower surface of the fixed die core, and the fixed die core is fitted and installed on the top of the cylinder through the fixed die core groove in a clamping manner.

[0008] Further, in the above-mentioned light alloy semi-solid melt preparation and injection extrusion casting forming equipment, a sprue groove is machined on the sprue, and a sprue bushing convex ring is provided on one side where the sprue bushing is fitted and installed on the sprue. Through the cooperation of the sprue groove and the sprue bushing convex ring, the sprue bushing is fitted and installed on the sprue.

[0009] In another aspect of the present invention, a method for preparing a light alloy semi-solid melt and injection extrusion casting forming is provided. The method is implemented by using the above-mentioned light alloy semi-solid melt preparation and injection extrusion casting forming equipment, and includes the following steps: I. Equipment preheating Preheat the moving die frame and the fixed die frame respectively, and preheat the cylinder; Turn on the infrared heaters covering the head, middle and tail of the material pipe of the material pipe to preheat the material pipe; II. Semi-solid melt preparation Using the intelligent prediction module of the melt microstructure, the process parameters for preparing the semi-solid melt are determined by predicting the microstructure based on the unified phase-field model. The process parameters for preparing the semi-solid melt include the melt temperature, stirring speed, and stirring time. Perform the preparation of the semi-solid melt according to the determined process parameters. Among them, performing the preparation of the semi-solid melt according to the determined process parameters includes: Heating of the material pipe: Heat the head, middle, and tail of the material pipe to the corresponding temperatures respectively to ensure that the temperature of the melt reaches the determined melt temperature when it reaches the head of the material pipe. Feeding and stirring: Feed the light alloy particles through the feed hopper. Based on the determined stirring speed and stirring time, use the stirring screw to transport the light alloy particles into the material pipe and send them from the tail of the material pipe through the middle of the material pipe to the head of the material pipe. III. Injection and feeding Control the moving die frame to move downward until the guide rod on the moving die frame enters the guide sleeve on the fixed die frame to complete the mold closing. Start the injection cylinder to make the screw head at the front end of the stirring screw inject the semi-solid melt stored in the front end of the head of the material pipe into the nozzle cavity of the nozzle at a high speed and then into the preheated material cylinder. IV. Extrusion casting and forming Push the semi-solid melt in the material cylinder into the mold cavity through the fixed die core. After the filling is completed, keep the pressure on the semi-solid melt so that the semi-solid melt solidifies under pressure. Control the moving die frame to move upward to complete the mold opening. Control the pushing plate to move towards the fixed die frame direction, and use the ejector rod to eject the formed casting adhered to the mold cavity.

[0010] Furthermore, in the above method for preparing the light alloy semi-solid melt and injection extrusion casting and forming, the evolution equation of the unified phase-field model is expressed as: ; ; ; Among them, ; ; ; ; ; ; ; In the formula, is the phase-field order parameter, is time, is the number of grains, is the local order parameter of the th grain, is the relaxation time, is the characteristic relaxation time, is the minimum liquid-phase solute diffusion coefficient, is the thermal diffusion coefficient, is the number of alloy components including the matrix component and solute components, is the rd solute component among the alloy components excluding the matrix component, is the equilibrium distribution coefficient, is the dimensionless supersaturation, is the ratio of the thermocapillary length to the chemicocapillary length, is the liquid-phase solute diffusion coefficient, is the interface energy anisotropy function, is the diffusion interface width, is the characteristic diffusion interface width, is the coupling coefficient, is the dimensionless temperature, is the solid-phase solute diffusion coefficient, is the anisotropy strength, is the orientation angle, taking random values between 0 and 2π, is the adjustment parameter, , is the time iteration scale, taking the value of is the temperature, is the melting point, is the liquidus slope, is the liquid-phase solute concentration, is the latent heat of fusion, is the specific heat, is the symbol for partial derivative, represents the partial derivative operation with respect to time, represents the gradient operation, is the symbol of the Laplace operator, and are intermediate parameters.

[0011] Furthermore, in the above method for preparing and injection-extrusion casting forming of the light alloy semi-solid melt, the process parameters for preparing the semi-solid melt are determined by the following method: Determine the parameters according to the light alloy system , , , , , , , , , , , , , , , , , ; Taking the melt temperature parameter , the stirring speed parameter , and the stirring time parameter as input parameters, according to different input parameters, using the unified phase field model to obtain the microstructure morphology under different input parameter combinations, and screening out the best melt temperature, stirring speed, and stirring time as the best process parameters for semi-solid melt preparation according to the spheroidization degree of the grains in the microstructure morphology.

[0012] Furthermore, in the above method for preparing and injection-extrusion casting of light alloy semi-solid melt, the steps of preheating the equipment include: Turn on the mold temperature controller, the moving mold electric heating plate, and the fixed mold electric heating plate to preheat the moving mold frame and the fixed mold frame respectively, and start the heating jacket of the material cylinder to preheat the material cylinder. Among them, the preheating temperature of the mold temperature controller is set to 295 - 305 °C, and the heating temperatures of the moving mold electric heating plate, the fixed mold electric heating plate, and the heating jacket of the material cylinder are all set to 595 - 605 °C until the temperature inside the material cylinder monitored by the thermocouple in the material cylinder reaches 545 - 555 °C and the temperature inside the mold cavity monitored by the mold thermocouple reaches 295 - 305 °C; Turn on the infrared heaters wrapped around the head, middle, and tail of the material tube to preheat the material tube until the temperature inside the material tube monitored by the thermocouple in the material tube reaches 295 - 305 °C.

[0013] Furthermore, in the above method for preparing and injection-extrusion casting of light alloy semi-solid melt, the steps of preparing the semi-solid melt according to the determined process parameters include: Heating of the material tube: Use the corresponding infrared heaters to heat and raise the temperature of the head, middle, and tail of the material tube respectively. The heating temperature of the tail area of the material tube is set to 575 - 585 °C; the heating temperature of the middle area of the material tube is set to 595 - 605 °C; the heating temperature of the head area of the material tube is set to 620 °C to ensure that the temperature of the melt reaches 620 °C when it reaches the head of the material tube; Feeding and stirring: The light alloy particles are fed through the feed hopper, and the rotation of the stirring screw is controlled at a stirring speed of 100 r / min and a stirring time of 30 s. The stirring screw is used to convey the light alloy particles into the feed pipe and send them from the tail of the feed pipe through the middle of the feed pipe to the head of the feed pipe.

[0014] Further, in the above-mentioned method for preparing and injection-extrusion casting of light alloy semi-solid melt, the injection feeding step includes: The water-based graphite lubricant is evenly sprayed on the inner wall of the cylinder, the magnesium oxide release agent is evenly sprayed on the surface of the mold cavity in the fixed mold core and the moving mold core, argon is pre-injected into the interior of the cylinder, and the moving mold frame is controlled to move downward until the guide rod on the moving mold frame enters the guide sleeve on the fixed mold frame to complete mold closing. The injection cylinder is started, and the screw head at the front end of the stirring screw injects the semi-solid melt stored in the front end of the head of the feed pipe into the nozzle cavity of the nozzle at a high speed and then into the preheated cylinder.

[0015] Further, in the above-mentioned method for preparing and injection-extrusion casting of light alloy semi-solid melt, the extrusion casting step includes: The injection rod and the injection head are controlled to move upward, pushing the semi-solid melt in the cylinder into the mold cavity through the fixed mold core. After the filling is completed, continuous pressure is applied to the injection rod and the injection head to hold the pressure on the semi-solid melt, so that the semi-solid melt solidifies under pressure. The moving mold frame is controlled to move upward to complete mold opening. The pushing plate is controlled to move towards the fixed mold frame, and the ejector rod is used to eject the formed casting adhered to the mold cavity. After the ejecting is completed, the moving mold frame is controlled to move downward to complete mold closing, and the ejector rod is reset under the driving action of the reset rod.

[0016] Further, in the above-mentioned method for preparing and injection-extrusion casting of light alloy semi-solid melt, a casting cleaning step is also included: The casting is placed on a steel flat plate and naturally cooled to room temperature. After cooling, the surface of the casting is polished with sandpaper, and then washed and dried with anhydrous ethanol.

[0017] Further, in the above-mentioned method for preparing and injection-extrusion casting of light alloy semi-solid melt, in the feeding and stirring step, the feeding amount of the light alloy particles each time is set to 295 - 305 g.

[0018] Further, in the above-mentioned method for preparing and injection-extrusion casting of light alloy semi-solid melt, in the injection feeding step, the stirring screw is pushed at a speed of 2.4 - 2.6 m / s.

[0019] Furthermore, in the above-mentioned light alloy semi-solid melt preparation and injection extrusion casting molding method, in the extrusion casting molding step, the injection rod and the injection head are controlled to move upward at a speed of 36~40mm / s. After the filling is completed, a holding pressure of 38~42 tons is continuously applied to the injection rod and the injection head to maintain the semi-solid melt for 29~31s.

[0020] Furthermore, in the above-mentioned light alloy semi-solid melt preparation and injection extrusion casting molding method, in the extrusion casting molding step, after the mold opening is completed, the injection cylinder is started, and the stirring screw is pulled backward to reset; the injection rod and the injection head are controlled to move downward and reset.

[0021] Furthermore, in the above-mentioned light alloy semi-solid melt preparation and injection extrusion casting molding method, the light alloy is AZ91D magnesium alloy.

[0022] The light alloy semi-solid melt preparation and injection extrusion casting molding equipment and method of the present invention adopts temperature and speed control mechanical stirring technology to prepare the semi-solid melt + injection extrusion casting molding, which can realize the integrated process from preparation to molding of the semi-solid melt, eliminating the step of melt transfer, and effectively avoiding the oxidation and temperature runaway problems of the melt during the transfer process on the basis of ensuring the simplicity of the process flow, which is of great significance for improving the controllability of the semi-solid melt and the stability of the semi-solid molded castings and product quality. Compared with the prior art, the light alloy semi-solid melt preparation and injection extrusion casting molding equipment and method of the present invention have the following advantages and beneficial effects: The melt microstructure intelligent prediction module is coupled with a unified phase field model to predict the changes in microstructure morphology under different process parameters during the preparation of semi-solid melts. The optimal process parameters such as melt temperature, stirring speed, stirring time, etc. during the preparation of semi-solid melts are determined based on the prediction results to prepare a semi-solid melt with stable quality, thereby optimizing the melt preparation process and improving the performance of castings. By designing the material cylinder in the fixed mold of the extrusion casting molding unit, adding a gate sleeve to the material cylinder and assembling it with the nozzle of the melt preparation unit, the melt preparation unit and the extrusion casting molding unit are seamlessly connected, and the prepared semi-solid melt is directly injected from the nozzle into the material cylinder for extrusion casting molding; The use of electric heating plates, cylinder heating sleeves and mold temperature controllers to perform oil-electric internal and external synergistic heating of the mold can accurately control the temperature of the semi-solid melt, improve the stability of semi-solid processing, and enhance the quality of light alloy semi-solid molding castings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the relevant drawings. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. In the drawings: Figure 1 is a schematic diagram of the overall structure of the equipment for preparing and injection-extrusion casting of light alloy semi-solid melt of the present invention; Figure 2 is a schematic diagram of the structure of the connection part between the melt preparation unit and the extrusion casting unit in the equipment for preparing and injection-extrusion casting of light alloy semi-solid melt of the present invention; Figure 3 is an exploded schematic diagram of the internal structure of the extrusion casting unit in the equipment for preparing and injection-extrusion casting of light alloy semi-solid melt of the present invention; Figure 4 is a three-dimensional structure schematic diagram of the injection feeding part of the semi-solid melt in the equipment for preparing and injection-extrusion casting of light alloy semi-solid melt of the present invention; Figure 5 is Figure 4 a sectional view taken along the A-A direction of; Figure 6 is a schematic diagram of the principle of intelligent prediction of the melt microstructure based on the unified phase field model in the method for preparing and injection-extrusion casting of light alloy semi-solid melt of the present invention; Figures 7 to 10 is a schematic diagram of the structure of the equipment for preparing and injection-extrusion casting of light alloy semi-solid melt of the present invention, Figures 7 to 10 showing the state diagrams at different stages in the process of implementing the method for preparing and injection-extrusion casting of light alloy semi-solid melt of the present invention; Figure 11 is a microstructural diagram of a casting prepared by using the method for preparing and injection-extrusion casting of light alloy semi-solid melt of the present invention; Figure 12 is another microstructural diagram of a casting prepared by using the method for preparing and injection-extrusion casting of light alloy semi-solid melt of the present invention; Figure 13 is a microstructural diagram of a casting prepared by using the extrusion casting process of the prior art; Figure 14 is another microstructural diagram of a casting prepared by using the extrusion casting process of the prior art; Figure 15 is a schematic diagram of the mechanical property test results of the as-cast mechanical properties of the castings obtained by extrusion casting; Figure 16It is obtained by squeeze casting, and is a schematic diagram of the mechanical property test results after T6 heat treatment of the casting.

[0024] Description of the reference numerals in the drawings: 1. Moving die heat insulation plate, 2. Die foot fixing plate, 3. Pushing plate, 4. Pushing fixing plate, 5. Die foot, 6. Ejector rod, 7. Return rod, 8. Moving die electric heating plate, 9. Moving die frame, 10. Mold temperature controller, 11. Mold thermocouple, 12. Heating oil pipe, 13. Cylinder thermocouple, 14. Fixed die electric heating plate, 15. Fixed die fixing plate, 16. Fixed die heat insulation plate, 17. Workbench, 18. Fixed die frame, 19. Cylinder, 19.1 Gate, 19.2 Gate groove, 20. Injection head, 21. Injection rod, 22. Cylinder heating sleeve, 23. Sprue bush, 23.1 Sprue bush convex ring, 24. Sprue bush fixing plate, 25. Flange backing plate, 26. Check ring, 27. Support ring, 28. Infrared heater, 29. Guide pillar, 30. Feed pipe, 31. Fixed bolt, 32. Feed inlet guide sleeve, 33. Feed inlet fixing seat, 34. Motor guide sleeve, 35. Motor fixing seat, 36. Oil cylinder fixing seat, 37. Injection oil cylinder, 38. Piston rod, 39. Servo motor, 40. Motor shaft, 41. Coaxiality adjustment device, 42. Feed hopper, 43. Stirring screw, 44. Feed pipe thermocouple, 45. Screw head, 46. Flange, 47. Nozzle, 47.1 Nozzle cavity, 48. Fixed die core, 48.1 Fixed die core groove, 49. Moving die core, 50. Dividing cone. Detailed implementation manners

[0025] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0026] First of all, it should be noted that in this article, "light alloy" refers to an alloy formed by fusing two or more metal elements (such as aluminum, magnesium, titanium, etc.) with a density less than or equal to 4.5 g / cm³.

[0027] Such as Figures 1 to 5As shown in the figure, the equipment for preparing and injection-extrusion casting of light alloy semi-solid melt mainly includes an intelligent prediction module for melt microstructure, a melt preparation unit, and an extrusion casting unit. The melt preparation unit is horizontally arranged and includes an injection oil cylinder 37, a piston rod 38, an oil cylinder fixing seat 36, a servo motor 39, a motor shaft 40, a motor fixing seat 35, a motor guide sleeve 34, a coaxiality adjustment device 41, a guide post 29, a feed port guide sleeve 32, a feed port fixing seat 33, a feed hopper 42, a stirring screw 43, a material pipe 30, an infrared heater 28, a material pipe thermocouple 44, and a nozzle 47. The extrusion casting unit is vertically arranged on a workbench 17 and includes a fixed mold frame 18, a fixed mold core 48, a material cylinder 19, a sprue bushing 23, a sprue bushing fixing plate 24, a pressure head 20, a pressure rod 21, a moving mold frame 9, a moving mold core 49, a flow divider cone 50, a moving mold electric heating plate 8, a fixed mold electric heating plate 14, a material cylinder heating sleeve 22, a mold temperature controller 10, and an ejection assembly.

[0028] The servo motor 39 is installed on the motor fixing seat 35, and the motor shaft 40 of the servo motor 39 is connected to the stirring screw 43 via the coaxiality adjustment device 41. The oil cylinder fixing seat 36 is arranged outside the motor fixing seat 35, that is, compared with the motor fixing seat 35, the oil cylinder fixing seat 36 is farther from the stirring screw 43, and the injection oil cylinder 37 is installed on the oil cylinder fixing seat 36. The guide post 29 is fixed between the workbench 17 and the oil cylinder fixing seat 36, the motor guide sleeve 34 is sleeved on the guide post 29, the motor fixing seat 35 is fixedly connected to the motor guide sleeve 34, and the piston rod 38 of the injection oil cylinder 37 is connected to the motor fixing seat 35.

[0029] The material pipe 30 is divided into three parts: the head of the material pipe, the middle of the material pipe, and the tail of the material pipe. The feed inlet fixing seat 33 is arranged between the coaxiality adjusting device 41 and the tail of the material pipe 30. The side of the feed inlet fixing seat 33 is fixedly connected to the tail of the material pipe by bolts. An inlet hopper 42 is arranged on the upper part of the feed inlet fixing seat 33. The lower part of the feed inlet fixing seat 33 is fixedly connected with a feed inlet guide sleeve 32. The feed inlet guide sleeve 32 is sleeved on the guide post 29 and fixed to the guide post 29 by a fixing bolt 31. The feeding end of the stirring screw 43 penetrates through the feed inlet fixing seat 33. The end of the stirring screw 43 extending out of the feed inlet fixing seat 33 is connected to the motor shaft 40 of the servo motor 39. The inlet hopper 42 arranged on the upper part of the feed inlet fixing seat 33 communicates with the feeding end of the stirring screw 43. The rest of the stirring screw 43 is installed in the material pipe 30. The discharging end of the stirring screw 43 is equipped with a support ring 27 for supporting and installing the stirring screw 43, a screw head 45 for pushing the material, and a check ring 26 for preventing reverse backflow. The nozzle 47 is connected to the head of the material pipe 30 through a flange 46 and bolts. The head, middle, and tail of the material pipe 30 are respectively covered with an infrared heater 28 and correspondingly equipped with a material pipe thermocouple 44. The infrared heater 28 is used to heat the material pipe 30. The material pipe thermocouple 44 is used to monitor the temperatures of the head, middle, and tail of the material pipe in real time and feedback to the infrared heater 28 to accurately control the temperature of the material pipe 30.

[0030] At the bottom of the squeeze casting forming unit, there are a fixed mold heat insulation plate 16 and a fixed mold fixing plate 15 fixed on the workbench 17 by a pressing plate. The fixed mold frame 18 is installed on the fixed mold fixing plate 15. The material cylinder 19 is installed in the fixed mold frame 18. The injection head 20 and the injection rod 21 are installed in the material cylinder 19. The fixed mold core 48 is fitted and installed at the top of the material cylinder 19. The outside of the material cylinder 19 is covered with a material cylinder heating sleeve 22 for heating the material cylinder 19. And a material cylinder thermocouple 13 is configured on the material cylinder 19, which is used to monitor the temperature inside the material cylinder 19 in real time and feedback to the material cylinder heating sleeve 22 to accurately control the temperature of the material cylinder 19.

[0031] On one side of the material cylinder 19 facing the nozzle 47, a gate 19.1 is provided. The sprue bush 23 with a heat preservation function is fitted and installed on the gate 19.1. The sprue bush fixing plate 24 is connected between the sprue bush 23 and the flange 46 by screws. The sprue bush fixing plate 24 is concentrically installed with the sprue bush 23 and internally connected. The nozzle 47 is inserted into the sprue bush fixing plate 24 and the sprue bush 23, and its nozzle cavity 47.1 communicates with the gate 19.1 of the material cylinder 19. And as described above, the nozzle 47 is connected to the head of the material pipe 30 of the material pipe through the flange 46. Thus, the melt in the material pipe 30 can directly enter the material cylinder 19 through the nozzle 47 for squeeze casting molding. In addition, on one side of the fixed mold frame 18 facing the nozzle 47, a flange backing plate 25 is provided to support and fix the flange 46. Thus, a reliable connection is achieved between the melt preparation unit and the squeeze casting molding unit, realizing the process integration of semi-solid melt preparation - transportation - molding.

[0032] Preferably, the sprue bush 23 is coated with a heating device (not shown), so that while fixing the nozzle 47, the melt during transportation can be heated and insulated to ensure the quality of the melt.

[0033] Preferably, a fixed mold core groove 48.1 is provided on the lower surface of the fixed mold core 48. Through the fixed mold core groove 48.1, the fixed mold core 48 is fitted and installed on the top of the material cylinder 19 in a clamping manner.

[0034] Preferably, a gate groove 19.2 is machined on the gate 19.1 on the side of the material cylinder 19. On one side where the sprue bush 23 is fitted and installed onto the gate 19.1, a sprue bush convex ring 23.1 is provided. Thus, through the cooperation of the gate groove 19.2 and the sprue bush convex ring 23.1, the sprue bush 23 is fitted and installed on the gate 19.1.

[0035] The movable mold frame 9 is installed on the upper part of the fixed mold frame 18, and the movable mold frame 9 and the fixed mold frame 18 are mutually positioned and aligned through guide rods (not shown) and matching guide sleeves (not shown). The movable mold core 49 is installed in the movable mold frame 9, and a diverter cone 50 is connected to the movable mold core 49. The movable mold core 49 and the fixed mold core 48 jointly form a mold cavity. The ejector assembly is arranged above the movable mold frame 9, including a push plate 3, a pusher fixing plate 4, a push rod 6, and a reset rod 7, which are used to implement the ejector action after the casting of the casting is completed. The upper part of the movable mold frame 9 is provided with mold feet 5 on both sides of the ejection assembly, and the push plate 3 and the push fixing plate 4 are fitted between the mold feet 5 on both sides to ensure that the movable mold frame 9 is level and thus ensure stable installation. The upper part of the mold foot 5 is installed with a mold foot fixing plate 2, and the upper part of the mold foot fixing plate 2 is installed with a movable mold insulation plate 1. The ejector rod 6 and the reset rod 7 are installed on the lower bottom surface of the pusher fixing plate 4, and the free ends of the ejector rod 6 and the reset rod 7 pass through the movable mold frame 9 and the movable mold core 49. The ejector rod 6 and the reset rod 7 are arranged so that the ejector rod 6 is directly facing the mold cavity and the reset rod 7 is deviated from the mold cavity, and the length of the reset rod 7 is slightly greater than the length of the ejector rod 6.

[0036] The movable mold frame 9 is coated with a movable mold electric heating plate 8 for electrically heating the movable mold frame 9, and the fixed mold frame 18 is coated with a fixed mold electric heating plate 14 for electrically heating the fixed mold frame 18. The movable mold frame 9 and the fixed mold frame 18 are both provided with oil circuits, and the mold temperature controller 10 is connected to the oil circuits of the movable mold frame 9 and the fixed mold frame 18 via a heating oil pipe 12, so that the movable mold frame 9 and the fixed mold frame 18 can be heated by heating oil. A mold thermocouple 11 is arranged on the movable mold core 49, which is used to monitor the temperature in the mold cavity in real time and feed back to the movable mold electric heating plate 8, the fixed mold electric heating plate 14, and the mold temperature controller 10 to achieve precise control of the mold cavity temperature.

[0037] The melt microstructure intelligent prediction module included in the light alloy semi-solid melt preparation and injection extrusion casting molding equipment of the present invention is used to determine the semi-solid melt preparation process parameters by predicting the microstructure based on the unified phase field model. The semi-solid melt preparation process parameters may include, for example, melt temperature, stirring speed, and stirring time, thereby achieving the purpose of optimizing the melt preparation process and improving the casting performance. The working process of the melt microstructure intelligent prediction module is specifically referred to the following description of the light alloy semi-solid melt preparation and injection extrusion casting molding method of the present invention.

[0038] The method for preparing a light alloy semi-solid melt and injection extrusion casting molding of the present invention is implemented by using the above-mentioned light alloy semi-solid melt preparation and injection extrusion casting molding equipment, and comprises the following steps: 1. Equipment preheating Preheat the movable mold frame 9 and the fixed mold frame 18 respectively, and preheat the material cylinder 19; Turn on the infrared heaters 28 covering the head, middle, and tail of the material pipe 30 to preheat the material pipe 30. II. Preparation of semi-solid melt Using the intelligent prediction module for melt microstructure, based on the unified phase field model, determine the semi-solid melt preparation process parameters by predicting the microstructure. The semi-solid melt preparation process parameters include melt temperature, stirring speed, and stirring time. Carry out the semi-solid melt preparation according to the determined process parameters. Among them, carrying out the semi-solid melt preparation according to the determined process parameters specifically includes the following: Material pipe heating: Heat the head, middle, and tail of the material pipe 30 to the corresponding temperatures respectively to ensure that the temperature of the melt reaches the determined melt temperature when it reaches the head of the material pipe. Feeding and stirring: Feed the light alloy particles through the feed hopper. Based on the determined stirring speed and stirring time, use the stirring screw 43 to transport the light alloy particles into the material pipe 30 and send them from the tail of the material pipe through the middle of the material pipe to the head of the material pipe. III. Injection feeding Control the moving die frame 9 to move downward until the guide rod on the moving die frame 9 enters the guide sleeve on the fixed die frame 18 to complete the mold closing. Start the injection oil cylinder 37 so that the screw head 45 at the front end of the stirring screw 43 injects the semi-solid melt stored in the front end of the head of the material pipe 30 into the nozzle cavity 47.1 of the nozzle 47 at high speed and then into the preheated material cylinder 19. IV. Extrusion casting forming Push the semi-solid melt in the material cylinder 19 into the mold cavity through the fixed die core 48. After the filling is completed, keep the pressure on the semi-solid melt so that the semi-solid melt solidifies under pressure. Control the moving die frame 9 to move upward to complete the mold opening. Control the push plate 3 to move towards the fixed die frame 18, and use the ejector rod 6 to eject the formed casting adhered to the mold cavity.

[0039] In the embodiment of the present invention, by repeating the above steps of feeding and stirring, injection feeding, and extrusion casting forming, batch castings can be continuously extruded and cast.

[0040] Furthermore, in the embodiment of the present invention, the evolution equation of the unified phase field model is expressed as: ; ; ; Among them, ; ; ; ; ; ; ; In the formula, is the phase field order parameter, is the time, is the number of grains, is the th local order parameter of the th grain, is the relaxation time, is the characteristic relaxation time, is the minimum liquid phase solute diffusion coefficient, is the thermal diffusion coefficient, is the number of alloy components including the matrix component and the solute component, is the th solute component among the alloy components except the matrix component, is the equilibrium distribution coefficient, is the dimensionless supersaturation, is the ratio of the thermocapillary length to the chemicocapillary length, is the liquid phase solute diffusion coefficient, is the interfacial energy anisotropy function, is the diffusion interface width, is the characteristic diffusion interface width, is the coupling coefficient, is the dimensionless temperature, is the solid phase solute diffusion coefficient, is the anisotropy strength, is the orientation angle, taking random values between 0 and 2π, is the adjustment parameter, , is the time iteration scale, with a value of is the temperature, is the melting point, is the liquidus slope, is the liquid phase solute concentration, is the latent heat of fusion, is the specific heat, is the symbol for partial derivative, represents the partial derivative operation with respect to time, represents the gradient operation, is the Laplace operator symbol, and is an intermediate parameter.

[0041] Based on the unified phase field model defined above, the process parameters for preparing the semi-solid melt are determined in the following manner: Determine the parameters according to the light alloy system , , , , , , , , , , , , , , , , , ; Taking the melt temperature parameter , the stirring speed parameter , and the stirring time parameter as input parameters, according to different input parameters, the microstructure morphology under different input parameter combinations is obtained by using the unified phase field model. According to the spheroidization degree of the grains in the microstructure morphology, the optimal melt temperature, stirring speed, and stirring time are selected as the optimal process parameters for preparing the semi-solid melt.

[0042] In the embodiment of the present invention, for the above-set input parameters, the selected optimal melt temperature is 620 °C, the optimal stirring speed is 100 r / min, and the optimal stirring time is 30 s. The melt temperature , the stirring speed , and the stirring time are used as the optimal process parameters for preparing the semi-solid melt.

[0043] Furthermore, in the embodiment of the present invention, the equipment preheating step further includes the following content: Turn on the mold temperature controller 10, the moving mold electric heating plate 8, and the fixed mold electric heating plate 14, and preheat the moving mold frame 9 and the fixed mold frame 18 respectively. Start the cylinder heating jacket 22 to preheat the cylinder 19. Among them, the preheating temperature of the mold temperature controller 10 is set to 295 - 305 °C, and the heating temperatures of the moving mold electric heating plate 8, the fixed mold electric heating plate 14, and the cylinder heating jacket 22 are all set to 595 - 605 °C until the temperature inside the cylinder 19 monitored by the cylinder thermocouple 13 reaches 545 - 555 °C and the temperature inside the mold cavity monitored by the mold thermocouple 11 reaches 295 - 305 °C; Turn on the infrared heaters 28 covering the head, middle, and tail of the material pipe 30 to preheat the material pipe 30 until the temperature inside the material pipe 30 monitored by the material pipe thermocouple 44 reaches 295 - 305°C.

[0044] In the embodiment of the present invention, by simultaneously turning on the mold temperature controller 10, the moving mold electric heating plate 8, the fixed mold electric heating plate 14, and the material cylinder heating sleeve 22 for heating, the oil - electric internal and external collaborative heating of the equipment can be achieved, improving the heating efficiency and ensuring the uniformity of equipment preheating.

[0045] Furthermore, in the embodiment of the present invention, based on the above - specifically determined optimal process parameters for semi - solid melt preparation, the steps for semi - solid melt preparation according to the determined process parameters further include the following: Material pipe heating: Use the corresponding infrared heaters 28 to heat and raise the temperature of the head, middle, and tail of the material pipe 30 respectively. The heating temperature of the tail area of the material pipe is set to 575 - 585°C; the heating temperature of the middle area of the material pipe is set to 595 - 605°C; the heating temperature of the head area of the material pipe is set to 620°C to ensure that the temperature of the melt reaches 620°C when it reaches the head of the material pipe. Feeding and stirring: Feed the light alloy particles through the feed hopper 42, control the rotation of the stirring screw 43 at a stirring speed of 100 r / min and a stirring time of 30 s. Use the stirring screw 43 to transport the light alloy particles into the material pipe 30 and send them from the tail of the material pipe through the middle to the head of the material pipe.

[0046] In the embodiment of the present invention, the tail area of the material pipe is used as the heating - up section, the middle area of the material pipe is used as the heat - preservation section, and the head area of the material pipe is used as the homogenization section. The temperatures of the head, middle, and tail of the material pipe can be measured by the material pipe thermocouples 44 correspondingly configured in these three areas. Through the three - stage heating and temperature - raising of the material pipe 30, it can be ensured that the temperature of the melt reaches 620°C, the melt temperature in the above - mentioned optimal process parameters, when it reaches the head of the material pipe.

[0047] In the embodiment of the present invention, the rotation of the stirring screw 43 is driven and controlled by the servo motor 39. During the transportation of the light alloy particles, the rotating stirring screw 43 applies a shear force to the light alloy particles. At the same time, under the heating of the infrared heaters 28 outside the material pipe 30, the light alloy particles start to melt in the tail area of the material pipe, transform from solid particles to semi - solid melt in the middle area of the material pipe, and complete the preparation of the semi - solid melt in the head area of the material pipe. Among them, when the stirring time reaches 30 s, the semi - solid melt is transported and stored at the front end inside the head of the material pipe under the action of the stirring screw 43 for subsequent semi - solid melt injection operation.

[0048] Further, as a preferred embodiment of the embodiment of the present invention, in the feeding and stirring steps defined above, the feeding amount of the light alloy particles each time is set to 295-305 g.

[0049] Further, in the embodiment of the present invention, the injection feeding step further includes the following: Spray the water-based graphite lubricant evenly on the inner wall of the cylinder 19, spray the magnesium oxide release agent evenly on the surface of the mold cavity in the fixed mold core 48 and the moving mold core 49, pre-inject argon into the interior of the cylinder 19, control the moving mold frame 9 to move downward until the guide rod on the moving mold frame 9 enters the guide sleeve on the fixed mold frame 18 to complete mold closing; Start the injection oil cylinder 37, so that the screw head 45 at the front end of the stirring screw 43 injects the semi-solid melt stored in the front end of the head of the material pipe into the nozzle cavity 47.1 of the nozzle 47 at a high speed and then into the preheated cylinder 19.

[0050] In the embodiment of the present invention, by spraying the water-based graphite lubricant evenly on the inner wall of the cylinder 19, it can be ensured that the injection head 20 and the injection rod 21 will not rub against the inner wall of the cylinder 19 during the upward and downward movements; by spraying the magnesium oxide release agent evenly on the surface of the mold cavity in the fixed mold core 48 and the moving mold core 49, it can be ensured that the casting can be smoothly demolded; by pre-injecting argon into the interior of the cylinder 19, it can be ensured that the argon atmosphere inside the cylinder 19 can prevent the semi-solid melt from oxidizing and burning when it is in the cylinder 19.

[0051] In the embodiment of the present invention, the moving mold frame 9 is controlled to move downward by starting the mold opening and closing drive mechanism (not shown).

[0052] In the embodiment of the present invention, when it is necessary to inject the semi-solid melt stored in the front end of the head of the material pipe into the nozzle cavity 47.1 of the nozzle 47 at a high speed and then into the preheated cylinder 19, start the injection oil cylinder 37, so that the piston rod 38 of the injection oil cylinder 37 pushes the connected motor fixing seat 35, and the motor guide sleeve 34 fixedly connected to the motor fixing seat 35 moves forward along the guide post 29 (i.e., moves in the direction of the material pipe 30), whereby the servo motor 39 mounted on the motor fixing seat 35 also moves forward accordingly, and the stirring screw 43 connected to the motor shaft 40 of the servo motor 39 also moves forward accordingly, so that the screw head 45 at the front end of the stirring screw 43 can inject the semi-solid melt stored in the front end of the head of the material pipe into the nozzle cavity 47.1 of the nozzle 47 at a high speed and then into the preheated cylinder 19. Among them, the injection feeding direction of the semi-solid melt is shown by the arrow A1 in Figure 5 as shown by the arrow A1.

[0053] Further, as a preferred embodiment of the embodiment of the present invention, in the injection feeding step defined above, the stirring screw 43 is pushed at a speed of 2.4 to 2.6 m / s, so that the screw head 45 at the front end of the stirring screw 43 injects the semi-solid melt stored in the front end of the head of the material pipe into the nozzle cavity 47.1 of the nozzle 47 at a high speed and then injects it into the preheated material cylinder 19.

[0054] Further, in the embodiment of the present invention, the squeeze casting forming step further includes the following contents: Control the injection rod 21 and the injection head 20 to move upward, push the semi-solid melt in the material cylinder 19 to enter the mold cavity through the fixed mold core 48, and continuously apply pressure to the injection rod 21 and the injection head 20 after the filling is completed to perform pressure holding on the semi-solid melt, so that the semi-solid melt solidifies under pressure; Control the moving mold frame 9 to move upward to complete mold opening; Control the push plate 3 to move towards the fixed mold frame 18, use the ejector rod 6 to eject the formed casting adhered to the mold cavity, and control the moving mold frame 9 to move downward after the ejection is completed to complete mold closing, and make the ejector rod 6 reset under the driving action of the reset rod 7.

[0055] In the embodiment of the present invention, the injection rod 21 and the injection head 20 are controlled to move upward by starting the injection driving mechanism (not shown) to push the semi-solid melt in the material cylinder 19 to enter the mold cavity through the fixed mold core 48, wherein, for the injection feeding direction of the semi-solid melt, see Figure 5 as shown by the arrow A2 in. Continuously apply pressure to the injection rod 21 and the injection head 20 after the filling is completed to perform pressure holding on the semi-solid melt, so that the semi-solid melt solidifies under pressure.

[0056] In the embodiment of the present invention, the moving mold frame 9 is controlled to move upward by starting the mold opening and closing driving mechanism to complete mold opening.

[0057] In the embodiment of the present invention, the push plate 3 is controlled to move towards the fixed mold frame 18 by starting the ejection driving mechanism (not shown), so that the ejector rod 6 moves downward with the push plate 3 to eject the formed casting adhered to the mold cavity. After the ejection is completed, the mold opening and closing driving mechanism is started to control the moving mold frame 9 to move downward to complete mold closing. During the mold closing process, the reset rod 7 protruding downward together with the push plate 3 and the ejector rod 6 is pushed back to its original position by the reaction of the fixed mold core 48, thereby driving the push plate 3 and the ejector rod 6 to return to their positions, so that the ejector rod 6 is reset under the driving action of the reset rod 7 to complete the squeeze casting forming of the light alloy semi-solid melt.

[0058] Further, as a preferred embodiment of the embodiment of the present invention, in the above-defined squeeze casting forming step, to facilitate subsequent injection squeeze casting forming, after the mold is opened, the injection oil cylinder 37 is started, and the stirring screw rod 43 is pulled backward to reset; the injection rod 21 and the injection head 20 are controlled to move downward to reset.

[0059] Specifically, the injection oil cylinder 37 is started, so that the piston rod 38 of the injection oil cylinder 37 pulls the connected motor fixing seat 35 to move backward, thereby pulling the stirring screw rod 43 backward to reset, and the injection driving mechanism is started to control the injection rod 21 and the injection head 20 to move downward to reset.

[0060] Further, as a preferred embodiment of the embodiment of the present invention, in the above-defined squeeze casting forming step, the injection rod 21 and the injection head 20 are controlled to move upward at a moving speed of 36-40 mm / s, and after the filling is completed, a holding pressure of 38-42 tons is continuously applied to the injection rod 21 and the injection head 20, and the semi-solid melt is held under pressure for 29-31 s.

[0061] Further, in the embodiment of the present invention, the method for preparing and injection squeeze casting forming of the light alloy semi-solid melt of the present invention may further include a casting cleaning step: placing the casting on a steel flat plate, naturally cooling to room temperature, using sandpaper to polish the surface of the casting after cooling, and then cleaning and drying with anhydrous ethanol.

[0062] As a specific embodiment, in the equipment and method for preparing and injection squeeze casting forming of the light alloy semi-solid melt of the present invention, the mold opening and closing driving mechanism and the injection driving mechanism are both hydraulic oil cylinders, and the ejection driving mechanism is a knockout oil cylinder.

[0063] The following takes the production and preparation of AZ91D magnesium alloy castings as a specific example to detail the method for preparing and injection squeeze casting forming of the light alloy semi-solid melt of the present invention. The chemical material used in this example is: AZ91D magnesium alloy particles, deionized water, anhydrous ethanol, argon, water-based graphite lubricant, magnesium oxide mold release agent, and the preparation dosages are as follows:

[0064] The method for preparing and injection squeeze casting forming of the light alloy semi-solid melt in the embodiment of the present invention includes the following steps: I. Equipment preheating (1) Turn on the mold temperature controller 10, the moving mold electric heating plate 8, and the fixed mold electric heating plate 14 to preheat the moving mold frame 9 and the fixed mold frame 18 respectively. Start the heating sleeve 22 of the material cylinder to preheat the material cylinder 19. Among them, the preheating temperature of the mold temperature controller 10 is set to 300 °C, the heating power of the moving mold electric heating plate 8 and the fixed mold electric heating plate 14 is 6000 w, and the heating power of the heating sleeve 22 of the material cylinder is 1000 w. The heating temperatures of the moving mold electric heating plate 8, the fixed mold electric heating plate 14, and the heating sleeve 22 of the material cylinder are all set to 600 °C. Monitor the temperature inside the mold cavity through the mold thermocouple 11 and the temperature inside the material cylinder 19 through the material cylinder thermocouple 13 to ensure that the temperature inside the material cylinder 19 reaches 550 °C and the temperature inside the mold cavity reaches 300 °C.

[0065] (2) First, clean the inner wall of the material pipe 30 with a metal brush, and then clean the inner surface of the material pipe 30 with anhydrous ethanol and deionized water to make the inner surface of the material pipe 30 smooth, flat, and clean. Turn on the infrared heaters 28 wrapped around the head, middle, and tail of the material pipe 30 to preheat the material pipe 30. Monitor the temperature of the material pipe 30 through the material pipe thermocouple 44 to ensure that the temperature inside the material pipe 30 reaches 300 °C.

[0066] II. Preparation of semi-solid melt (1) Use the intelligent prediction module of the melt microstructure to determine the semi-solid melt preparation process parameters by predicting the microstructure based on the unified phase field model. The semi-solid melt preparation process parameters include melt temperature, stirring speed, and stirring time. The specific implementation process is as follows: For AZ91D magnesium alloy, , that is, the number of alloy components of AZ91D magnesium alloy is 3, including the matrix component magnesium (Mg), the solute components aluminum (Al), and zinc (Zn), , which represent aluminum (Al) and zinc (Zn) respectively. According to the input parameters of the AZ91D magnesium alloy system 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 , the input values are shown in Table 1 below: Table 1 Thermal physical properties of AZ91D magnesium alloy

[0067] Input the melt temperature parameters separately , and input the stirring speed parameters separately at each melt temperature , and finally input the stirring time parameter . According to different input parameters, the microstructural morphologies under different parameter combinations are obtained. Based on the spheroidization degree of the grains in the microstructural morphology, the melt temperature , stirring speed , and stirring time are selected as the optimal process parameters for semi-solid melt preparation, so as to optimize the melt preparation process and improve the properties of the casting .

[0068] (2) As shown in Figure 7 , semi-solid melt preparation is carried out according to the optimal process parameters determined by the intelligent prediction module of the melt microstructure based on the unified phase field model. Among them, the melt temperature is 620 °C, the stirring speed is 100 r / min, and the stirring time is 30 s. The specific process of semi-solid melt preparation includes: Heating of the material pipe: Start the infrared heater 28, and adjust the temperature of each part of the material pipe 30 according to the feedback signal of the material pipe thermocouple 44, so that the heating temperatures of the tail, middle and head of the material pipe 30 are 580 °C, 600 °C and 620 °C in sequence. Through the three-stage heating and temperature rise of the material pipe 30, it is ensured that the temperature of the melt can reach the melt temperature of 620 °C in the above optimal process parameters when it reaches the head of the material pipe

[0069] Feeding and stirring: Feed the AZ91D magnesium alloy particles through the feed hopper 42, and drive the stirring screw 43 to rotate by the servo motor 39 (as shown by the arrow R in Figure 7 ). The rotation speed of the servo motor 39 is set according to the stirring speed of 100 r / min in the above optimal process parameters. The servo motor 39 controls the stirring screw 43 to stir, shear and convey the AZ91D magnesium alloy particles through the coaxiality adjusting device 41. The AZ91D magnesium alloy particles are conveyed from the tail of the stirring screw 43 to the material pipe 30 and from the tail of the material pipe through the middle of the material pipe to the head of the material pipe under the condition of being heated and subjected to shear force. During this process, the AZ91D magnesium alloy particles are transformed from a solid state into a semi-solid melt

[0070] Preferably, the AZ91D magnesium alloy particles are added to the material pipe 30 in batches through the feed hopper 42 to prevent the stirring screw 43 from being stuck due to excessive single addition. For example, the feeding amount of the AZ91D magnesium alloy particles each time is set to 300 g

[0071] The rotation time of the stirring screw 43 is set according to the stirring time of 30 s in the above-mentioned optimal process parameters. When the stirring time reaches 30 s, the semi-solid melt is conveyed and stored at the front end inside the head of the material pipe under the action of the stirring screw 43 for the injection operation of the semi-solid melt.

[0072] III. Injection and feeding As Figure 8 shown, the injection and feeding are carried out through the following operations: (1) Uniformly spray the water-based graphite lubricant on the inner wall of the material cylinder 19 with a thickness of about 0.1 mm to ensure that the injection plunger 20 and the injection rod 21 will not rub against the inner wall of the material cylinder 19 during the up and down movements; uniformly spray the magnesium oxide release agent on the surface of the mold cavity inside the fixed mold core 48 and the moving mold core 49 with a thickness of about 0.15 mm to ensure the smooth demolding of the casting; pre-inject argon into the inside of the material cylinder 19 to ensure an argon atmosphere inside the material cylinder 19 to prevent the oxidation and combustion of the semi-solid melt when it is in the material cylinder 19; start the mold opening and closing drive mechanism to control the downward movement of the moving mold frame 9 with a clamping force of 450 tons until the guide rod on the moving mold frame 9 enters the guide sleeve on the fixed mold frame 18 to complete the mold clamping.

[0073] (2) Start the injection oil cylinder 37. The piston rod 38 of the injection oil cylinder 37 pushes the connected motor fixing seat 35 forward at a speed of 2.5 m / s (as Figure 8 shown by the arrow F in the figure). The motor guide sleeve 34 fixedly connected to the motor fixing seat 35 moves along the guide post 29 towards the material pipe 30, so that the servo motor 39 installed on the motor fixing seat 35 also moves forward accordingly. Thus, the stirring screw 43 connected to the motor shaft 40 of the servo motor 39 also moves forward correspondingly. As a result, the screw head 45 at the front end of the stirring screw 43 injects the semi-solid melt stored at the front end inside the head of the material pipe into the nozzle cavity 47.1 of the nozzle 47 at a high speed and then into the preheated material cylinder 19. High-speed injection at up to 2.5 m / s can reduce the heat loss of the melt during transportation and ensure that a stable semi-solid melt can be obtained in the material cylinder 19.

[0074] IV. Extrusion casting forming As Figure 9 and 10 shown, the extrusion casting forming is carried out through the following operations: (1) Start the injection drive mechanism to control the injection rod 21 and the injection plunger 20 to move upward at a moving speed of 38 mm / s (as Figure 9 shown by the arrow U21 in the figure), push the semi-solid melt through the fixed mold core 48 into the mold cavity. After the filling is completed, continuously apply a holding pressure of 40 tons to the injection rod 21 and the injection plunger 20 to hold the pressure on the semi-solid melt for 30 s, so that the semi-solid melt solidifies under pressure.

[0075] (2) Start the above-mentioned mold opening and closing drive mechanism to control the moving mold frame 9 to move upward (as shown by the arrow U9 in Figure 10 ), complete the mold opening, start the injection oil cylinder 37, and the piston rod 38 of the injection oil cylinder 37 pulls the connected motor fixing seat 35 to move backward (as shown by the arrow B in Figure 10 ), thereby pulling the stirring screw 43 backward to reset, and start the injection driving mechanism to control the injection rod 21 and the injection head 20 to move downward and reset (as shown by the arrow D21 in Figure 10 ).

[0076] (3) Start the ejection driving mechanism to control the ejector plate 3 to move towards the fixed mold frame 18, and the ejector rod 6 moves downward with the ejector plate 3 (as shown by the arrow D6 in Figure 10 ), eject the formed casting adhered to the mold cavity, and after the ejection is completed, start the above-mentioned mold opening and closing drive mechanism to control the moving mold frame 9 to move downward to complete the mold closing. The ejector rod 6 is reset under the driving action of the reset rod 7, and the AZ91D magnesium alloy casting is obtained.

[0077] By repeating the above steps of feeding and stirring, injection feeding, and squeeze casting forming, batch castings can be continuously squeeze cast and formed.

[0078] V. Casting Cleaning Place the AZ91D magnesium alloy casting on a steel flat plate, naturally cool it to room temperature, and after cooling, polish the surface of the casting with sandpaper, and then clean and dry it with anhydrous ethanol.

[0079] Detect, analyze, and characterize the macroscopic morphology, microstructure, and mechanical properties of the castings prepared by the light alloy semi-solid melt preparation and injection squeeze casting forming method of the embodiments of the present invention, and compare them with the castings prepared by the conventional squeeze casting forming process of the existing technology.

[0080] Figure 11 and Figure 12 are the microstructure diagrams of the castings prepared by the light alloy semi-solid melt preparation and injection squeeze casting forming method of the present invention, Figure 13 and Figure 14 are the microstructure diagrams of the castings prepared by the squeeze casting forming process of the existing technology. It can be found that the microstructure of the castings prepared by the semi-solid injection + squeeze casting process of the present invention is basically rose-like equiaxed crystals, belonging to the typical semi-solid non-dendritic microstructure, and the grains are effectively refined. However, there are a large number of developed dendrites in the microstructure of the castings prepared by the squeeze casting forming process of the existing technology, and the Mg 17 Al 12 precipitation phases are continuously distributed in a network, which will seriously affect the mechanical properties of the product.

[0081] Figure 15 and Figure 16The mechanical properties test results of the castings obtained by squeeze casting are shown in FIG. Figure 15 The results of the casting mechanical properties test are shown. Figure 16 The figure shows the mechanical properties test results of the casting after being placed in a resistance furnace for T6 heat treatment at 420℃ / 16h+200℃ / 8h. Figure 15 and Figure 16 Curves 1 and 2 in the figure refer to the #1 sample and #2 sample of the castings prepared by the prior art extrusion casting molding process, respectively, and curves 3 and 4 refer to the #1 sample and #2 sample of the castings prepared by the semi-solid injection + extrusion casting process of the present invention, respectively. It can be seen that the castings using the prior art extrusion casting molding process have a maximum as-cast tensile strength of 170MPa and a maximum elongation of 4.1%, while the castings using the semi-solid injection + extrusion casting process of the present invention have a as-cast tensile strength of up to 200MPa and an elongation of up to 7.5%; the castings using the prior art extrusion casting molding process have a tensile strength of 225~240MPa and an elongation of 3.2~5.5% after T6 heat treatment, while the castings using the semi-solid injection + extrusion casting process of the present invention have a tensile strength of up to 275~295MPa and an elongation of up to 8.3~10.1% after T6 heat treatment. Therefore, compared with the conventional extrusion casting molding process of the prior art, the mechanical properties of the castings prepared by the light alloy semi-solid melt preparation and injection extrusion casting molding method of the present invention are significantly improved.

[0082] In summary, the light alloy semi-solid melt preparation and injection extrusion casting molding equipment and method of the present invention are developed to address the problems in the prior art of melt transfer, temperature control, large deviation between the actual temperature and the preset temperature during pouring, and easy to cause incomplete filling and inclusions of the casting during semi-solid extrusion casting. The semi-solid melt preparation + injection extrusion casting molding are carried out by temperature and speed control mechanical stirring technology, which can realize an integrated process from preparation to molding of the semi-solid melt, eliminate the step of melt transfer, and effectively avoid oxidation and temperature runaway problems of the melt during transfer while ensuring the simplicity of the process flow. It is of great significance to improve the controllability of the semi-solid melt, the stability of the semi-solid molded casting and the product quality.

[0083] Compared with the prior art, the light alloy semi-solid melt preparation and injection extrusion casting molding equipment and method of the present invention have at least the following advantages and beneficial effects: The present invention predicts the microstructure morphology changes under different process parameters in the semi-solid melt preparation process by coupling the melt microstructure intelligent prediction module with the unified phase field model, and determines the optimal process parameters such as melt temperature, stirring speed, stirring time, etc. in the semi-solid melt preparation process according to the prediction results, so as to prepare a semi-solid melt with stable quality, thereby achieving the purpose of optimizing the melt preparation process and improving the casting performance; In the present invention, the material cylinder 19 is designed inside the fixed die of the die of the squeeze casting forming unit, and a sprue bushing 23 is added to the material cylinder 19 for assembly with the nozzle 47 of the melt preparation unit, so as to achieve seamless docking between the melt preparation unit and the squeeze casting forming unit, and the prepared semi-solid melt is directly fed from the nozzle 47 into the material cylinder 19 by means of melt injection for squeeze casting forming; The present invention uses an electric heating plate, a material cylinder heating jacket 22 and a mold temperature controller 10 to perform oil-electric internal and external collaborative heating on the mold, which can accurately control the temperature of the semi-solid melt, improve the stability of semi-solid processing, and enhance the quality of light alloy semi-solid formed castings.

[0084] It should be noted that in this article, unless otherwise clearly specified and defined, the term "connection" or its synonyms should be understood in a broad sense. For example, "connection" can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above terms in the present invention can be understood according to specific circumstances. Moreover, expressions such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. At the same time, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. In addition, in this article, "front", "rear", "left", "right", "upper" and "lower" are all referenced with respect to the placement state shown in the drawings.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light alloy semi-solid melt preparation and injection extrusion casting forming device, characterized in that, It includes an intelligent prediction module for melt microstructure, a melt preparation unit, and an extrusion casting forming unit. The melt preparation unit is horizontally arranged and includes an injection oil cylinder, a piston rod, an oil cylinder fixing seat, a servo motor, a motor shaft, a motor fixing seat, a motor guide sleeve, a coaxiality adjustment device, guide columns, a feed port guide sleeve, a feed port fixing seat, a feed hopper, a stirring screw, a material pipe, an infrared heater, a material pipe thermocouple, and a nozzle; The extrusion casting forming unit is vertically arranged on the workbench and includes a fixed mold frame, a fixed mold core, a material cylinder, a sprue bushing, a sprue bushing fixing plate, a shot sleeve, a shot rod, a moving mold frame, a moving mold core, a flow divider cone, a moving mold electric heating plate, a fixed mold electric heating plate, a material cylinder heating jacket, a mold temperature controller, and an ejection assembly, where: The intelligent prediction module for melt microstructure is used to determine the semi-solid melt preparation process parameters by predicting the microstructure based on the unified phase field model. The semi-solid melt preparation process parameters include melt temperature, stirring speed, and stirring time; The servo motor is installed on the motor fixing seat. The motor shaft is connected to the stirring screw via the coaxiality adjustment device. The oil cylinder fixing seat is arranged outside the motor fixing seat. The injection oil cylinder is installed on the oil cylinder fixing seat. The guide columns are fixed between the workbench and the oil cylinder fixing seat. The motor guide sleeve is sleeved on the guide columns. The motor fixing seat is fixedly connected to the motor guide sleeve. The piston rod is connected to the motor fixing seat; The material pipe is divided into three parts: a material pipe head, a material pipe middle part, and a material pipe tail part. The feed port fixing seat is arranged between the coaxiality adjustment device and the material pipe tail part of the material pipe. The side part of the feed port fixing seat is fixedly connected to the material pipe tail part. The feed hopper is arranged on the upper part of the feed port fixing seat. The lower part of the feed port fixing seat is fixedly connected with the feed port guide sleeve. The feed port guide sleeve is sleeved on the guide columns and fixed to the guide columns by fixing bolts. The feed end of the stirring screw penetrates through the feed port fixing seat. The end of the stirring screw extending out of the feed port fixing seat is connected to the motor shaft. The feed hopper arranged on the upper part of the feed port fixing seat is communicated with the feed end of the stirring screw. The rest of the stirring screw is installed in the material pipe. The discharge end of the stirring screw is equipped with a support ring for supporting the installation of the stirring screw, a screw head for pushing the material, and a check ring for preventing reverse backflow. The nozzle is connected to the material pipe head of the material pipe by a flange and bolts. The material pipe head, the material pipe middle part, and the material pipe tail part of the material pipe are respectively covered with an infrared heater and correspondingly equipped with a material pipe thermocouple; At the bottom of the extrusion casting forming unit, a fixed mold heat insulation plate and a fixed mold fixing plate fixed to the workbench by a pressing plate are provided. The fixed mold frame is installed on the fixed mold fixing plate. The material cylinder is installed in the fixed mold frame. The shot sleeve and the shot rod are installed in the material cylinder. The fixed mold core is fitted and installed at the top of the material cylinder. The outside of the material cylinder is covered with a material cylinder heating jacket and correspondingly equipped with a material cylinder thermocouple; On one side of the material cylinder facing the nozzle, a gate is provided. The sprue bushing is fitted and installed on the gate. The sprue bushing fixing plate is connected between the sprue bushing and the flange. The sprue bushing fixing plate is concentrically installed with the sprue bushing and internally connected. The nozzle is inserted into the sprue bushing fixing plate and the sprue bushing, and the nozzle cavity of the nozzle communicates with the gate. On one side of the fixed mold frame facing the nozzle, there is a flange backing plate for supporting and fixing the flange. The moving mold frame is installed on the upper part of the fixed mold frame, and the moving mold frame and the fixed mold frame are positioned and aligned with each other through guide rods and matching guide sleeves. The moving mold core is installed in the moving mold frame. A flow splitter cone is connected to the moving mold core. The moving mold core and the fixed mold core jointly form a mold cavity. The ejection assembly is arranged above the moving mold frame and includes a push plate, a push plate fixing plate, ejector rods, and a return rod. On both sides of the ejection assembly on the upper part of the moving mold frame, there are mold feet. The push plate and the push plate fixing plate are fitted and installed between the mold feet on both sides. The ejector rods and the return rod are installed on the lower bottom surface of the push plate fixing plate, and the free ends of the ejector rods and the return rod both pass through the moving mold frame and the moving mold core. The ejector rods are arranged to face the mold cavity, and the return rods are arranged to deviate from the mold cavity. Moreover, the length of the return rod is greater than the length of the ejector rod. The outside of the moving mold frame is covered with the moving mold electric heating plate, and the outside of the fixed mold frame is covered with the fixed mold electric heating plate. Moreover, both the moving mold frame and the fixed mold frame are provided with oil circuits. The mold temperature controller is connected to the oil circuits of the moving mold frame and the fixed mold frame via heating oil pipes.

2. The light alloy semi-solid melt preparation and injection extrusion casting forming equipment according to claim 1, characterized in that, The sprue bushing is covered with a heating device to heat and keep warm the conveyed melt.

3. The light alloy semi-solid melt preparation and injection extrusion casting forming equipment according to claim 1, characterized in that, On the lower surface of the fixed mold core, there is a fixed mold core groove, and the fixed mold core is fitted and installed on the top of the material cylinder in a clamping manner through the fixed mold core groove.

4. The light alloy semi-solid melt preparation and injection extrusion casting forming equipment according to claim 1, characterized in that, The gate is machined with a gate groove. On one side where the sprue bushing is fitted and installed on the gate, there is a sprue bushing convex ring. Through the cooperation of the gate groove and the sprue bushing convex ring, the sprue bushing is fitted and installed on the gate.

5. A method for preparing a light alloy semi-solid melt and injection extrusion casting, the method being implemented by using the light alloy semi-solid melt preparation and injection extrusion casting equipment as described in claim 1, characterized in that, The light alloy semi-solid melt preparation and injection extrusion casting forming method includes the following steps: I. Equipment preheating Preheat the moving mold frame and the fixed mold frame respectively, and preheat the material cylinder; Turn on the infrared heaters covering the head, middle, and tail of the material pipe of the material pipe to preheat the material pipe; II. Semi-solid melt preparation Utilize the melt microstructure intelligent prediction module to determine the semi-solid melt preparation process parameters based on the unified phase field model by predicting the microstructure. The semi-solid melt preparation process parameters include melt temperature, stirring speed, and stirring time; Perform semi-solid melt preparation according to the determined process parameters. Among them, performing semi-solid melt preparation according to the determined process parameters includes: Material pipe heating: Heat the head, middle, and tail of the material pipe to the corresponding temperatures respectively to ensure that the temperature of the melt reaches the determined melt temperature when it reaches the head of the material pipe; Feeding and stirring: The light alloy particles are fed through the feed hopper. Based on the determined stirring speed and stirring time, the stirring screw is used to transport the light alloy particles into the feed pipe and send them from the tail of the feed pipe through the middle of the feed pipe to the head of the feed pipe; III. Injection feeding Control the moving die frame to move downward until the guide rod on the moving die frame enters the guide sleeve on the fixed die frame to complete mold closing; Start the injection oil cylinder, so that the screw head at the front end of the stirring screw injects the semi-solid melt stored in the front end of the head of the feed pipe into the nozzle cavity of the nozzle at a high speed and then into the preheated cylinder; IV. Extrusion casting forming Push the semi-solid melt in the cylinder into the mold cavity through the fixed die core. After the filling is completed, the semi-solid melt is kept under pressure to complete solidification under pressure; Control the moving die frame to move upward to complete mold opening; Control the push plate to move towards the fixed die frame direction, and use the ejector rod to eject the formed casting adhered to the mold cavity.

6. The preparation method of semi-solid light alloy melt and injection extrusion casting forming method according to claim 5, characterized in that, The evolution equation of the unified phase field model is expressed as: ； ； ； Among them, ； ； ； ； ； ； ； In the formula, is the phase-field order parameter, is time, is the number of grains, is the th local order parameter of the grain, is the relaxation time, is the characteristic relaxation time, is the minimum liquid-phase solute diffusion coefficient, is the thermal diffusion coefficient, is the number of alloy components including the matrix component and solute components, is the th solute component among the alloy components except the matrix component, is the equilibrium distribution coefficient, is the ratio of the thermocapillary length to the chemicocapillary length, is the liquid-phase solute diffusion coefficient, is the interfacial energy anisotropy function, is the diffusion interface width, is the characteristic diffusion interface width, is the coupling coefficient, is the dimensionless temperature, is the solid-phase solute diffusion coefficient, is the anisotropy strength, is the orientation angle, taking random values between 0 and 2π, is the adjustment parameter, is the time iteration scale, taking the value of , is the temperature, is the melting point, is the liquidus slope, is the liquid-phase solute concentration, is the latent heat of fusion, is the specific heat, is the solute concentration, is the symbol for partial derivative, represents the partial derivative operation with respect to time, represents the gradient operation, is the Laplace operator symbol, and are intermediate parameters.

7. The preparation method of the light alloy semi-solid melt and the injection extrusion casting forming method according to claim 6, characterized in that Determine the semi-solid melt preparation process parameters in the following ways: Determine parameters according to the light alloy system , , , , , , , , , , , , , , , , , ; With the melt temperature parameter , the stirring speed parameter , and the stirring time parameter as input parameters, according to the differences in the input parameters, the microstructure morphology under different input parameter combinations is obtained by using the unified phase field model. According to the degree of grain spheroidization of the microstructure morphology, the optimal melt temperature, stirring speed, and stirring time are selected as the optimal process parameters for semi-solid melt preparation.

8. The method for preparing and injection-extrusion casting of semi-solid melt of light alloy according to claim 5 or 7, characterized in that The steps of preheating the equipment include: Turn on the mold temperature controller, the moving die electric heating plate, and the fixed die electric heating plate, and preheat the moving die frame and the fixed die frame respectively. Start the cylinder heating jacket to preheat the cylinder. Among them, the preheating temperature of the mold temperature controller is set to 295 - 305 °C, and the heating temperatures of the moving die electric heating plate, the fixed die electric heating plate, and the cylinder heating jacket are all set to 595 - 605 °C until the temperature inside the cylinder monitored by the cylinder thermocouple reaches 545 - 555 °C and the temperature inside the mold cavity monitored by the mold thermocouple reaches 295 - 305 °C; Turn on the infrared heaters covering the head, middle, and tail of the feed pipe to preheat the feed pipe until the temperature inside the feed pipe monitored by the feed pipe thermocouple reaches 295 - 305 °C.

9. The preparation method of semi-solid melt of light alloy and injection extrusion casting forming method according to claim 5 or 7, characterized in that, The steps of preparing the semi-solid melt according to the determined process parameters include: Feed pipe heating: Use the corresponding infrared heaters to heat and raise the temperature of the head, middle, and tail of the feed pipe respectively. The heating temperature of the tail area of the feed pipe is set to 575 - 585 °C; the heating temperature of the middle area of the feed pipe is set to 595 - 605 °C; the heating temperature of the head area of the feed pipe is set to 620 °C to ensure that the temperature of the melt reaches 620 °C when it reaches the head of the feed pipe; Feeding and stirring: Feed the light alloy particles through the feed hopper, control the stirring screw to rotate at a stirring speed of 100 r / min and a stirring time of 30 s, and use the stirring screw to transport the light alloy particles into the feed pipe and send them from the tail of the feed pipe through the middle of the feed pipe to the head of the feed pipe.

10. The method for preparing and injection-extrusion casting of semi-solid melt of light alloy according to claim 5 or 7, characterized in that The injection feeding steps include: Evenly spray the water-based graphite lubricant on the inner wall of the cylinder, evenly spray the magnesium oxide release agent on the surface of the mold cavity inside the fixed die core and the moving die core, pre-inject argon into the cylinder, control the moving die frame to move downward until the guide rod on the moving die frame enters the guide sleeve on the fixed die frame to complete mold closing; Start the injection oil cylinder, so that the screw head at the front end of the stirring screw injects the semi-solid melt stored in the front end of the head of the feed pipe into the nozzle cavity of the nozzle at a high speed and then into the preheated cylinder.

11. The preparation method of semi-solid melt of light alloy and injection extrusion casting forming method according to claim 5 or 7, characterized in that, The squeeze casting forming step includes: Controlling the upward movement of the injection rod and the injection head, pushing the semi-solid melt in the material cylinder into the mold cavity through the fixed mold core, continuously applying pressure to the injection rod and the injection head after the filling is completed, performing pressure holding on the semi-solid melt, and enabling the semi-solid melt to solidify under pressure; Controlling the upward movement of the moving mold frame to complete mold opening; Controlling the pushing plate to move towards the fixed mold frame direction, using the ejector rod to eject the formed casting adhered to the mold cavity, controlling the downward movement of the moving mold frame after the ejecting is completed to complete mold closing, and enabling the ejector rod to reset under the driving action of the reset rod.

12. The method for preparing and injection-extrusion casting of semi-solid melt of light alloy according to claim 5 or 7, characterized in that It further includes a casting cleaning step: placing the casting on a steel flat plate, naturally cooling it to room temperature, using sandpaper to polish the surface of the casting after cooling, and then cleaning and drying it with absolute ethanol.

13. The preparation method of light alloy semi-solid melt and injection extrusion casting forming method according to claim 9, characterized in that, In the feeding and stirring step, the feeding amount of the light alloy particles each time is set to 295 - 305 g.

14. The method for preparing and injection-extrusion casting of a light alloy semi-solid melt according to claim 10, characterized in that, In the injection feeding step, the stirring screw is pushed at a speed of 2.4 - 2.6 m / s.

15. The method for preparing and injection-extrusion casting of a light alloy semi-solid melt according to claim 11, characterized in that, In the squeeze casting forming step, controlling the injection rod and the injection head to move upward at a moving speed of 36 - 40 mm / s, continuously applying a pressure holding pressure of 38 - 42 tons to the injection rod and the injection head after the filling is completed, and performing pressure holding on the semi-solid melt for 29 - 31 s.

16. The method for preparing a light alloy semi-solid melt and injection extrusion casting according to claim 11, characterized in that, In the squeeze casting forming step, after the mold opening is completed, starting the injection oil cylinder to pull the stirring screw backward to reset; controlling the injection rod and the injection head to move downward to reset.

17. The method for preparing and injection-extrusion casting of semi-solid melt of light alloy according to claim 5 or 7, characterized in that, The light alloy is AZ91D magnesium alloy.

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