Squeeze casting method and device

Abstract

The present application relates to an extrusion casting method and device, wherein the method includes: moving the upper mold downward by a direct extrusion casting mechanism so that the cavity between the upper mold and the lower mold forms a first filling cavity, and filling the first filling cavity with molten metal by an indirect extrusion casting mechanism; moving the upper mold downward by the direct extrusion casting mechanism to perform direct extrusion casting, and at the same time filling the cavity between the upper mold and the lower mold with molten metal by the indirect extrusion casting mechanism to switch from the first filling cavity to the second filling cavity; filling the second filling cavity with molten metal by the indirect extrusion casting mechanism, and moving the upper mold by the direct extrusion casting mechanism to perform direct extrusion casting to switch from the second filling cavity to the part filling cavity, thereby combining direct extrusion casting with indirect extrusion casting to take into account both part dimensional accuracy and effective filling and shrinkage compensation, thereby improving casting quality.

Description

Technical Field

[0001] The present application relates to the field of extrusion casting, and in particular to an extrusion casting method and device. Background Art

[0002] Lightweight materials such as aluminum alloys and magnesium alloys have strong advantages in reducing vehicle weight. Especially with the development of integrated extrusion casting technology, the application research of lightweight materials such as aluminum alloys and magnesium alloys in vehicle bodies has received more widespread attention.

[0003] Squeeze casting includes direct and indirect squeeze casting. Direct squeeze casting applies pressure directly to the molten metal, resulting in minimal pressure loss. However, this method results in poor dimensional accuracy and is suitable for simple parts. Indirect squeeze casting transfers pressure to the molten metal in the barrel, which is then indirectly transmitted to the workpiece via the runner. This allows for the formation of more complex parts with high precision and excellent surface quality. However, indirect squeeze casting suffers from long pressure transmission distances, significant pressure loss, and ineffective mold filling and feeding. Therefore, a squeeze casting method that balances part dimensional accuracy with effective mold filling and feeding is needed. Summary of the Invention

[0004] Based on this, the present application provides an extrusion casting method and device to take into account both part dimensional accuracy and effective mold filling and shrinkage compensation, thereby improving casting quality.

[0005] In one aspect, a squeeze casting method is provided, comprising:

[0006] Moving the upper mold downward by a direct extrusion casting mechanism so that the cavity between the upper mold and the lower mold forms a first filling cavity, and filling the first filling cavity with molten metal by an indirect extrusion casting mechanism;

[0007] The upper mold is moved downward by the direct extrusion casting mechanism to perform direct extrusion casting, and at the same time, the cavity between the upper mold and the lower mold is filled with molten metal by the indirect extrusion casting mechanism to switch from the first filling cavity to the second filling cavity;

[0008] The second filling cavity is filled with molten metal by the indirect extrusion casting mechanism, and the upper mold is moved by the direct extrusion casting mechanism to perform direct extrusion casting, so as to switch from the second filling cavity to the part filling cavity.

[0009] In one embodiment, the method of moving the upper mold downward by the direct extrusion casting mechanism so that the cavity between the upper mold and the lower mold forms a first filling cavity, and filling the first filling cavity with molten metal by the indirect extrusion casting mechanism includes:

[0010] Moving the upper mold at a first preset speed by the direct extrusion casting mechanism so that a gap between the upper mold and the lower mold becomes a filling gap to form the first filling cavity;

[0011] Filling the molten metal into the first filling cavity at a second preset speed and a preset volume by the indirect squeeze casting mechanism to perform indirect squeeze casting;

[0012] The preset volume is a first threshold value of the volume of the cast part.

[0013] In one embodiment, the direct extrusion casting mechanism is used to move the upper mold downward to perform direct extrusion casting, and the indirect extrusion casting mechanism is used to fill the cavity between the upper mold and the lower mold with molten metal to switch from the first filling cavity to the second filling cavity, including:

[0014] Moving the upper die downward at a third preset speed by the direct extrusion casting mechanism to perform direct extrusion casting, so that the gap between the upper die and the lower die becomes a liquid forging gap, thereby switching from the first filling cavity to the second filling cavity;

[0015] At the same time, the molten metal is filled into the cavity between the upper mold and the lower mold at a fourth preset speed by the indirect extrusion casting mechanism to perform indirect extrusion casting;

[0016] The molten metal in the cavity between the upper mold and the lower mold is transported to the feeding mechanism through the direct extrusion casting mechanism and the indirect extrusion casting mechanism, and the excess molten metal is transported to the slag ladle.

[0017] In one embodiment, the filling of the second filling cavity with molten metal by the indirect extrusion casting mechanism, and the moving of the upper mold by the direct extrusion casting mechanism to perform direct extrusion casting to switch from the second filling cavity to the part filling cavity, include:

[0018] Pressurizing and feeding the molten metal in the second filling cavity by an indirect squeeze casting mechanism, and pressurizing and feeding the molten metal in the second filling cavity by a feeding mechanism;

[0019] In response to the solid phase ratio of the molten metal in the second filling cavity reaching a preset solid phase threshold, the upper mold is moved by the direct extrusion casting mechanism to perform direct extrusion casting, so that the gap between the upper mold and the lower mold is the closing gap, so as to switch from the second filling cavity to the part filling cavity.

[0020] In one embodiment, the first preset speed is greater than the third preset speed, and the second preset speed is greater than the fourth preset speed.

[0021] In another aspect, a squeeze casting apparatus is provided, comprising:

[0022] An upper mold and a lower mold, wherein a cavity is formed between the upper mold and the lower mold, and the cavity includes a first filling cavity, a second filling cavity or a part filling cavity;

[0023] an indirect extrusion casting mechanism, for filling the mold cavity with molten metal by an indirect extrusion casting method to perform indirect extrusion casting;

[0024] The direct extrusion casting mechanism is used for moving the upper mold to perform direct extrusion casting.

[0025] In one embodiment, the upper mold is provided with an upper cavity, the lower mold is provided with a lower cavity, the upper mold is slidably arranged relative to the lower mold, and the upper cavity and the lower cavity form the cavity.

[0026] In one embodiment, the direct extrusion casting mechanism includes an upper driving mechanism and an upper driving push rod, the upper driving mechanism is used to push the upper driving push rod to move, and the upper mold is arranged on the upper driving push rod.

[0027] In one embodiment, the indirect extrusion casting mechanism includes a lower driving mechanism and a lower driving piston, the lower driving mechanism drives the lower driving piston to move, a lower piston cavity is provided on the lower mold, the lower driving piston is slidably provided in the lower piston cavity, and the lower piston cavity is communicated with the mold cavity.

[0028] In one embodiment, the mold further includes a feeding mechanism, wherein the feeding mechanism is arranged on the upper mold, the upper mold is provided with a feeding cavity, the feeding mechanism is provided with a feeding piston, the feeding piston is slidably arranged in the feeding cavity, and the feeding cavity is communicated with the mold cavity.

[0029] The above technical solution of the present application has the following advantages over the prior art:

[0030] (1) The above-mentioned squeeze casting method and apparatus combine the advantages of direct squeeze casting and indirect squeeze casting. Direct squeeze casting and indirect squeeze casting are performed simultaneously, taking into account both the dimensional accuracy of the parts and the effective filling and shrinkage compensation, thereby improving the casting quality of the parts. In addition, the squeeze casting method of the present application fully combines the advantages of direct squeeze casting and indirect squeeze casting. The molten metal flows easily, and large thin-walled parts can be cast. It not only solves the defects of indirect squeeze casting alone, such as cold shut and difficulty in filling the mold, but also solves the defect of direct squeeze casting alone, which is difficult to cast large integrated thin-walled parts. In addition, sufficient pressure maintenance and shrinkage compensation can be performed to solve defects such as shrinkage cavities and uneven mechanical properties.

[0031] (2) The above-mentioned extrusion casting method and device pressurizes the molten metal in the second filling cavity through an indirect extrusion casting mechanism, thereby achieving shrinkage compensation on the side near the gate end of the second filling cavity. At the same time, the molten metal at the shrinkage compensation mechanism is squeezed by the shrinkage compensation mechanism, and the side of the second filling cavity away from the gate end is synchronously pressurized and compensated. Two-end pressure-maintaining and shrinkage compensation is formed in the entire second filling cavity, eliminating shrinkage defects such as shrinkage cavities and shrinkage, and improving the density of parts. The two-end pressure-maintaining and shrinkage compensation can also effectively shorten the pressure transmission path, make the shrinkage compensation more sufficient, and fill the small parts of the parts more fully, effectively improving the shape accuracy of the parts. At the same time, solidification under pressure conditions can refine the grain size and improve the overall strength of the parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0033] Figure 1 This is a flow chart of the first method of the squeeze casting method provided in an embodiment of the present application;

[0034] Figure 2 is a flow chart of a second method of the squeeze casting method provided in an embodiment of the present application;

[0035] Figure 3 is a schematic structural diagram of an extrusion casting device provided in an embodiment of the present application;

[0036] Figure 4 yes Figure 3 A partial enlarged schematic diagram of point A in the middle;

[0037] Figure 5 2. It is a schematic diagram of the state of the first filling cavity of the squeeze casting device provided in an embodiment of the present application;

[0038] Figure 6 yes Figure 5 A partial enlarged schematic diagram of point B in the middle;

[0039] Figure 7 2. It is a schematic diagram of a state in which the squeeze casting device provided in an embodiment of the present application fills the first filling cavity with molten metal;

[0040] Figure 8 2. It is a schematic diagram of the state of the second filling cavity of the squeeze casting device provided in an embodiment of the present application;

[0041] Figure 9 yes Figure 8 A partial enlarged schematic diagram of point C in the middle;

[0042] Figure 10 Schematic diagram of the state of the part filling cavity of the squeeze casting device provided in an embodiment of the present application;

[0043] Figure 11 yes Figure 10 A partial enlarged schematic diagram of point D in the middle;

[0044] Figure 12 This is a schematic diagram of demoulding parts of the extrusion casting device provided in an embodiment of the present application.

[0045] Description of the accompanying drawings:

[0046] 1. Upper mold; 2. Lower mold; 3. Indirect extrusion casting mechanism; 4. Direct extrusion casting mechanism; 5. Upper cavity; 6. Lower cavity; 7. Upper drive mechanism; 8. Upper drive push rod; 9. Lower drive mechanism; 10. Lower drive piston; 11. Lower piston cavity; 12. Feeding mechanism; 13. Feeding cavity; 14. Feeding piston; 15. Casting frame; 16. Top bracket; 17. Middle bracket; 18. Bottom bracket; 19. Upper mold base; 20. Lower workbench; 21. Feeding drive mechanism; 22. Feeding runner; 23. Water sealing baffle; 24. Slag ladle; 25. Cavity; 26. First filling cavity; 27. Second filling cavity; 28. Part filling cavity. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0048] Example 1

[0049] Reference Figure 1 As shown, Figure 1 This is a flow chart of the first method of the extrusion casting method provided in an embodiment of the present application.

[0050] The method comprises the following steps:

[0051] S101, moving the upper mold downward by a direct extrusion casting mechanism so that the cavity between the upper mold and the lower mold forms a first filling cavity, and filling the first filling cavity with molten metal by an indirect extrusion casting mechanism;

[0052] The extrusion casting method of the present application combines direct extrusion casting with indirect extrusion casting, effectively improving the quality of extrusion casting. Specifically, the extrusion casting method of the present application first moves the upper mold through the direct extrusion casting mechanism, causing the upper mold to move in a direction close to the lower mold (preferably vertically), thereby forming a first filling cavity in the cavity between the upper and lower molds. After the first filling cavity is formed, the prepared molten metal is then filled into the first filling cavity through the indirect extrusion casting mechanism to perform indirect extrusion casting.

[0053] S102, moving the upper mold downward by the direct extrusion casting mechanism to perform direct extrusion casting, and simultaneously filling the cavity between the upper mold and the lower mold with molten metal by the indirect extrusion casting mechanism to switch from the first filling cavity to the second filling cavity; the volume of the first filling cavity is greater than the volume of the second filling cavity;

[0054] After the prepared molten metal is filled into the first filling cavity by the indirect extrusion casting mechanism, the upper mold is moved again by the direct extrusion mechanism, and then the molten metal in the cavity is directly extruded and casted by the direct extrusion mechanism; while direct extrusion casting is being performed by the direct extrusion mechanism, the indirect extrusion casting mechanism is also required to continue to fill the cavity between the upper mold and the lower mold with molten metal for indirect extrusion casting. Under the joint action of direct extrusion casting and indirect extrusion casting, the direct extrusion casting mechanism drives the upper mold to move toward the lower mold, resulting in a smaller volume of the cavity between the upper mold and the lower mold, thereby switching the cavity between the upper mold and the lower mold from the first filling cavity to the second filling cavity. Therefore, the volume of the second filling cavity is smaller than that of the first filling cavity.

[0055] S103, filling the second filling cavity with molten metal through the indirect extrusion casting mechanism, and moving the upper mold through the direct extrusion casting mechanism to perform direct extrusion casting, so as to switch from the second filling cavity to the part filling cavity.

[0056] After the first filling cavity is switched to the second filling cavity, the second filling cavity is filled with molten metal through the indirect extrusion casting mechanism. That is, indirect extrusion casting is performed through the indirect extrusion casting mechanism, that is, the second filling cavity is pressure-maintained and shrink-compensated to improve the extrusion casting quality. Finally, the upper mold is driven by the direct extrusion casting mechanism to move toward the lower mold to perform direct extrusion casting on the molten metal in the cavity, thereby switching the cavity between the upper and lower molds from the second filling cavity to the part filling cavity (the volume of the second filling cavity is larger than that of the part filling cavity). That is, the upper and lower molds are completely closed through the direct extrusion casting mechanism to achieve near forging forming. Finally, the second filling cavity is transformed into the part filling cavity. That is, the molten metal in the part filling cavity is completely solidified and becomes the final cast part.

[0057] Direct extrusion casting has low precision and good mold filling; indirect extrusion casting cannot effectively fill the mold and has high casting precision. The extrusion casting method of the present application combines direct extrusion casting with indirect extrusion casting. The cast parts can not only ensure high casting precision but also have excellent filling effect. Therefore, the present application combines the advantages of direct extrusion casting and indirect extrusion casting. The two casting methods of direct extrusion casting and indirect extrusion casting are carried out simultaneously, which improves the casting quality of the parts. In addition, the extrusion casting method of the present application fully combines the advantages of direct extrusion casting and indirect extrusion casting. The molten metal flows easily, and the casting of large thin-walled parts can be realized. It can not only solve the defects of cold shut and difficulty in filling the mold of indirect extrusion casting alone, but also solve the defect that direct extrusion casting alone is difficult to cast large integrated thin-walled parts. In addition, sufficient pressure maintenance and shrinkage compensation can be carried out to solve defects such as shrinkage holes and uneven mechanical properties.

[0058] In one embodiment, the method of moving the upper mold by the direct extrusion casting mechanism so that the cavity between the upper mold and the lower mold forms a first filling cavity, and filling the first filling cavity with molten metal by the indirect extrusion casting mechanism includes:

[0059] Moving the upper mold downward at a first preset speed by the direct extrusion casting mechanism so that a gap between the upper mold and the lower mold becomes a filling gap to form the first filling cavity;

[0060] Specifically, the upper mold and the lower mold are arranged in parallel, and preferably the upper mold and the lower mold are in a horizontal state. The size of the cavity formed by the upper mold and the lower mold can be adjusted by adjusting the distance between the upper mold and the lower mold. Therefore, the upper mold is moved downward at a first preset speed by the direct extrusion casting mechanism, so that the upper mold moves toward the lower mold, and then the gap between the upper mold and the lower mold is the filling gap. When the gap between the upper mold and the lower mold is the filling gap, the cavity formed by the upper mold and the lower mold is the first filling cavity. The filling gap is determined according to the thinnest thickness of the cast part, and the filling gap = (2 to 4) * the thinnest thickness of the part. Preferably, the filling gap = 3 * the thinnest thickness of the part. As Figure 5 and Figure 6 The filling gap d1 is shown. Furthermore, during this first filling period, the mold cavity is not filled with molten metal. Therefore, the upper mold can be moved at a higher speed when closing the upper and lower molds. The first preset speed is generally greater than 300 mm / s. In other words, the first preset speed is greater than the third preset speed to improve casting efficiency. Preferably, the first preset speed is 500 mm / s.

[0061] Filling the molten metal into the first filling cavity at a second preset speed and a preset volume by the indirect squeeze casting mechanism to perform indirect squeeze casting;

[0062] Specifically, after determining the first filling cavity according to the filling gap, the molten metal is filled into the first filling cavity at a second preset speed and a preset volume by the indirect extrusion casting mechanism to perform indirect extrusion casting on the molten metal in the first filling cavity, such as Figure 7The schematic diagram of molten metal filling is shown. In which, the indirect extrusion casting mechanism hydraulically injects the metal into the first filling cavity through the runner, and the volume of the molten metal injected into the first filling cavity is a preset volume, which is the first threshold value of the volume of the cast part, that is, the preset volume = (60% to 90%) * part volume. Preferably, the preset volume = 70% * part volume, so that the volume of molten metal in the cavity is just right when direct extrusion casting is subsequently performed by the direct extrusion casting mechanism. Too much will lead to waste of molten metal, and too little will lead to poor quality of the cast part, prone to shrinkage cavities and shrinkage, and even the part cannot be completely formed. In addition, when the indirect extrusion casting mechanism hydraulically injects the metal into the first filling cavity through a piston injection method, the piston's moving speed (second preset speed) is 0.05m / s to 1.00m / s, and the preferred second preset speed of the piston is 0.25m / s. At this time, during the process of filling the first filling cavity with molten metal at a second preset speed and preset volume through the indirect extrusion casting mechanism, the molten metal is filled from bottom to top, which can improve the casting quality. In addition, since the upper and lower molds are not completely closed, the space in the first filling cavity is larger, and therefore the gap within the first filling cavity is larger, the channel is smooth, and the flow resistance of the molten metal is small, allowing for easy filling. Secondly, since the mold cavity of the first filling cavity is larger, the internal air is easily discharged, the filling air resistance is small, and air entrapment and air entrapment defects will not occur. In addition, compared to the fully closed state, the contact area between the molten metal and the mold is small, the temperature loss is small, the molten metal has better fluidity, and the extrusion force is smaller.

[0063] In one embodiment, the direct extrusion casting mechanism is used to move the upper mold downward to perform direct extrusion casting, and the indirect extrusion casting mechanism is used to fill the cavity between the upper mold and the lower mold with molten metal to switch from the first filling cavity to the second filling cavity, including:

[0064] Moving the upper die downward at a third preset speed by the direct extrusion casting mechanism to perform direct extrusion casting, so that the gap between the upper die and the lower die becomes a liquid forging gap, thereby switching from the first filling cavity to the second filling cavity;

[0065] Specifically, the upper mold is moved downward by the direct extrusion casting mechanism at a third preset speed to perform direct extrusion casting on the molten metal in the cavity, so that the upper mold moves toward the lower mold, thereby making the gap between the upper mold and the lower mold a liquid forging gap. When the gap between the upper mold and the lower mold is the liquid forging gap, the cavity formed by the upper mold and the lower mold is the second filling cavity. The liquid forging gap = 0.05mm ~ 1.00mm, preferably, the liquid forging gap = 0.25mm. Figure 8 and Figure 9The filling gap d2 is shown. Furthermore, during the movement of the upper mold by the direct extrusion casting mechanism, the lower mold remains stationary. Since the first filling cavity is filled with molten metal, the movement speed of the upper mold needs to be reduced to improve casting quality. The upper mold then moves downward at a third preset speed of 0.5 mm / s to 5.0 mm / s, squeezing the molten metal. The molten metal is then filled into the cavity via direct extrusion casting. The third preset speed of the upper mold is preferably 2 mm / s. The first preset speed is greater than the third preset speed.

[0066] At the same time, the molten metal is filled into the cavity between the upper mold and the lower mold at a fourth preset speed by the indirect extrusion casting mechanism to perform indirect extrusion casting;

[0067] Specifically, while the upper mold is moved by the direct extrusion casting mechanism to perform direct extrusion casting on the molten metal in the cavity to form a second filling cavity, the molten metal is continuously filled into the cavity between the upper mold and the lower mold at a fourth preset speed by the indirect extrusion casting mechanism to perform indirect extrusion casting on the molten metal in the cavity. At this time, when the indirect extrusion casting mechanism hydraulically injects the metal into the cavity between the upper mold and the lower mold through the runner, the speed of the piston (the fourth preset speed) is reduced to 0.05-0.80 m / s, and the fourth preset speed is preferably 0.15 m / s, thereby reducing the speed at which the molten metal is filled into the cavity between the upper mold and the lower mold to improve the casting quality. Among them, the second preset speed is greater than the fourth preset speed. In this process, the two extrusion casting methods, direct extrusion casting and indirect extrusion casting, are carried out simultaneously until the upper mold and the lower mold are closed to the liquid forging gap.

[0068] The molten metal in the cavity between the upper mold and the lower mold is transported to the feeding mechanism through the direct extrusion casting mechanism and the indirect extrusion casting mechanism, and the excess molten metal is transported to the slag ladle.

[0069] Specifically, in the process of filling the molten metal into the cavity between the upper mold and the lower mold at a fourth preset speed through the indirect extrusion casting mechanism for indirect extrusion casting, and while the direct extrusion casting mechanism moves the upper mold for direct extrusion casting to form a second filling cavity for direct extrusion casting, the molten metal that continues to enter the cavity between the upper mold and the lower mold is filled into the shrinkage mechanism through the shrinkage runner, and the excess molten metal is transported to the slag ladle.

[0070] In one embodiment, the filling of the second filling cavity with molten metal by the indirect extrusion casting mechanism, and the moving of the upper mold by the direct extrusion casting mechanism to perform direct extrusion casting to switch from the second filling cavity to the part filling cavity, include:

[0071] Pressurizing and feeding the molten metal in the second filling cavity by an indirect squeeze casting mechanism, and pressurizing and feeding the molten metal in the second filling cavity by a feeding mechanism;

[0072] Specifically, the indirect squeeze casting mechanism performs indirect squeeze casting, that is, the indirect squeeze casting mechanism pressurizes the molten metal in the second filling cavity through the runner, achieving shrinkage compensation on the side of the second filling cavity near the gate end. At the same time, the compensation mechanism starts to work, squeezing the molten metal at the compensation mechanism to synchronously pressurize and compensate the side of the second filling cavity away from the gate end. Therefore, two-end pressure-maintaining and compensation are formed in the entire second filling cavity, eliminating shrinkage defects such as shrinkage cavities and porosity, and improving the density of the part. The two-end pressure-maintaining and compensation can also effectively shorten the pressure transmission path, ensuring more sufficient compensation and more complete filling of small parts of the part, effectively improving the shape accuracy of the part. At the same time, solidification under pressure conditions can refine the grain size and improve the overall strength of the part.

[0073] In response to the solid phase ratio of the molten metal in the second filling cavity reaching a preset solid phase threshold, the upper mold is moved by the direct extrusion casting mechanism to perform direct extrusion casting, so that the gap between the upper mold and the lower mold is the closing gap, so as to switch from the second filling cavity to the part filling cavity.

[0074] Specifically, after the pressure is maintained and the shrinkage is fed by the indirect extrusion casting mechanism and the shrinkage feeding mechanism, when the solid phase ratio of the molten metal in the second filling cavity reaches the preset solid phase threshold, the upper mold is moved by the direct extrusion casting mechanism to perform direct extrusion casting on the molten metal in the cavity, so that the gap between the upper mold and the lower mold is the mold closing gap, that is, the gap between the upper mold and the lower mold is zero, and the upper mold and the lower mold are completely closed, such as Figure 10 and Figure 11 As shown, the solidified molten metal in the second filling cavity is then subjected to a forming process similar to a forging process, which can form a high-performance forging layer on the surface of the part, further improving the density and overall strength of the part. At the same time, the compressive stress formed on the part surface helps to improve the fatigue strength and fatigue life of the part. The preset solid phase threshold is 60% to 80%, and preferably, the preset solid phase threshold is 70%.

[0075] In one embodiment, after the second filling cavity is switched to the part filling cavity, the method further includes:

[0076] The upper mold is separated from the lower mold, and the parts are demoulded.

[0077] Specifically, after the part filling cavity is formed and the approximate forging forming is completed, the upper mold and the lower mold can be separated by the direct extrusion casting mechanism, and the part is demoulded to complete the casting of the part. Figure 12shown.

[0078] Example 2

[0079] Reference Figure 2 As shown, Figure 2 This is a flow chart of the second method of the extrusion casting method provided in the embodiment of the present application. Figure 2 In the method shown, Figure 1 For the same or similar contents in the methods shown, please refer to Figure 1 The description in the method will not be repeated here.

[0080] S201, moving the upper mold downward at a first preset speed by the direct extrusion casting mechanism so that the gap between the upper mold and the lower mold becomes a filling gap, thereby forming the first filling cavity;

[0081] The upper mold and the lower mold are arranged parallel to each other, and preferably in a horizontal position. The size of the cavity formed by the upper and lower molds can be adjusted by adjusting the distance between the upper and lower molds. Therefore, the upper mold is moved downward by the direct extrusion casting mechanism at a first predetermined speed, so that the upper mold moves toward the lower mold, thereby forming a filling gap between the upper and lower molds. When the gap between the upper and lower molds forms the filling gap, the cavity formed by the upper and lower molds forms a first filling cavity.

[0082] S202, preparing molten metal, and filling the molten metal into the first filling cavity at a second preset speed and a preset volume through the indirect extrusion casting mechanism to perform indirect extrusion casting;

[0083] After preparing the required molten metal and determining the first filling cavity, the indirect squeeze casting mechanism fills the prepared molten metal into the first filling cavity at a second preset speed and volume, thereby performing indirect squeeze casting on the molten metal within the first filling cavity. The preset volume = 70% * part volume. The indirect squeeze casting mechanism hydraulically injects the metal into the first filling cavity through the runner using a piston injection method, with the piston moving at a second preset speed of 0.25 m / s.

[0084] S203, moving the upper mold downward at a third preset speed by the direct extrusion casting mechanism to perform direct extrusion casting, so that the gap between the upper mold and the lower mold becomes a liquid forging gap, thereby switching from the first filling cavity to the second filling cavity;

[0085] The direct extrusion casting mechanism moves the upper mold downward at a third preset speed to perform direct extrusion casting on the molten metal in the mold cavity, causing the upper mold to move closer to the lower mold. This creates a liquid forging gap between the upper and lower molds. When the gap between the upper and lower molds reaches the liquid forging gap, the cavity formed by the upper and lower molds becomes the second filling cavity. The liquid forging gap is 0.25 mm. Furthermore, during the movement of the upper mold by the direct extrusion casting mechanism, the lower mold remains stationary, and the upper mold moves downward at a third preset speed of 2 mm / s.

[0086] S204, simultaneously, filling the molten metal into the cavity between the upper mold and the lower mold at a fourth preset speed through the indirect extrusion casting mechanism to perform indirect extrusion casting;

[0087] The direct squeeze casting mechanism moves the upper die to directly squeeze cast the molten metal within the mold cavity, forming a second filled cavity. Simultaneously, the indirect squeeze casting mechanism continuously fills the cavity between the upper and lower molds with molten metal at a fourth preset speed, thereby indirectly squeezing the molten metal within the cavity. The piston speed of the indirect squeeze casting mechanism, when hydraulically injecting metal into the cavity between the upper and lower molds through the runner, is reduced to 0.15 m / s, thereby reducing the speed at which the molten metal fills the cavity between the upper and lower molds and improving casting quality. During this process, both direct and indirect squeeze casting methods proceed simultaneously until the upper and lower molds are closed to a liquid forging gap.

[0088] S205, transporting the molten metal in the cavity between the upper mold and the lower mold to a feeding mechanism through the direct extrusion casting mechanism and the indirect extrusion casting mechanism, and transporting excess molten metal to a slag ladle;

[0089] During the process of filling the molten metal into the cavity between the upper mold and the lower mold at a fourth preset speed through the indirect extrusion casting mechanism for indirect extrusion casting, and while the direct extrusion casting mechanism moves the upper mold for direct extrusion casting to form a second filling cavity for direct extrusion casting, the molten metal that continues to enter the cavity between the upper mold and the lower mold is filled into the feeding mechanism through the feeding runner, and the excess molten metal is transported to the slag ladle.

[0090] S206, pressurizing and feeding the molten metal in the second filling cavity by the indirect squeeze casting mechanism, and pressurizing and feeding the molten metal in the second filling cavity by the feeding mechanism;

[0091] The indirect squeeze casting mechanism performs indirect squeeze casting. Specifically, it pressurizes the molten metal in the secondary cavity through the runner, achieving shrinkage feeding on the side of the secondary cavity near the gate. Simultaneously, the feeding mechanism begins operating, squeezing the molten metal at the feeding mechanism to simultaneously pressurize and feed the side of the secondary cavity away from the gate. This creates two-terminal pressure-maintaining feeding throughout the secondary cavity, eliminating shrinkage defects and improving part density.

[0092] S207, in response to the solid phase ratio of the molten metal in the second filling cavity reaching a preset solid phase threshold, moving the upper mold by the direct extrusion casting mechanism to perform direct extrusion casting so that the gap between the upper mold and the lower mold becomes a closing gap, thereby switching from the second filling cavity to the part filling cavity;

[0093] After maintaining pressure and feeding through the indirect extrusion casting mechanism and the feeding mechanism, when the solid phase ratio of the molten metal in the second filling cavity reaches a preset solid phase threshold, the direct extrusion casting mechanism moves the upper mold to perform direct extrusion casting on the molten metal in the cavity, so that the gap between the upper and lower molds is the closing gap. That is, the gap between the upper and lower molds is zero, and the upper and lower molds are completely closed. The solidified molten metal in the second filling cavity is then subjected to a forming process similar to a forging process. This can form a high-performance forging layer on the surface of the part, further improving the density and overall strength of the part. At the same time, the compressive stress formed on the part surface helps to improve the fatigue strength and fatigue life of the part. The preset solid phase threshold is 70%.

[0094] S208, separating the upper mold from the lower mold and demoulding the parts.

[0095] After the part filling cavity is formed and the approximate forging forming is completed, the upper mold and the lower mold can be separated by the direct extrusion casting mechanism, and the part can be demoulded to complete the casting of the part.

[0096] It should be understood that although Figures 1 and 2 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figures 1 and 2 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0097] Example 3

[0098] Reference Figure 3-Figure 12 As shown, the squeeze casting device of this embodiment includes:

[0099] An upper mold 1 and a lower mold 2, wherein a cavity 25 is formed between the upper mold 1 and the lower mold 2, and the cavity 25 includes a first filling cavity 26, a second filling cavity 27 and a part filling cavity 28;

[0100] an indirect extrusion casting mechanism 3 for filling the mold cavity 25 with molten metal by an indirect extrusion casting method to perform indirect extrusion casting;

[0101] The direct extrusion casting mechanism 4 is used to move the upper mold 1 to perform direct extrusion casting.

[0102] Specifically, such as Figure 3 As shown, the extrusion casting device of the present application includes a casting frame 15, which includes a top bracket 16, a middle bracket 17, and a bottom bracket 18 connected sequentially from top to bottom. The direct extrusion casting mechanism 4 is disposed on the top bracket 16. The bottom of the direct extrusion casting mechanism 4 is connected to an upper mold base 19. The ends of the upper mold base 19 are slidably disposed on the middle bracket 17. The upper mold 1 is disposed at the bottom of the upper mold base 19. The sliding direction of the upper mold base 19 on the middle bracket 17 is preferably vertical, so that the direct extrusion casting mechanism 4 can drive the upper mold base 19 to move in the vertical direction, and the upper mold base 19 can then drive the upper mold 1 to move in the vertical direction. A lower workbench 20 is disposed on the bottom bracket 18, and the lower mold 2 is disposed on the top surface of the lower workbench 20. The lower mold 2 is located directly below the upper mold 1. The indirect extrusion casting mechanism 3 is disposed at the bottom of the lower workbench 20 so that the molten metal is injected vertically upward into the mold cavity 25 formed between the upper mold 1 and the lower mold 2. The mold cavity 25 includes a first filling cavity 26, a second filling cavity 27, and a part filling cavity 28. The extrusion casting device of the present application has a simple structure, and the direct extrusion casting mechanism 4 and the indirect extrusion casting mechanism 3 can be integrated into a single mold.

[0103] In one embodiment, an upper cavity 5 is provided on the upper mold 1 , and a lower cavity 6 is provided on the lower mold 2 . The upper mold 1 is slidably arranged relative to the lower mold 2 , and the upper cavity 5 and the lower cavity 6 form a cavity 25 .

[0104] like Figure 12As shown, an upper cavity 5 is provided at the bottom of the upper mold 1, and a lower cavity 6 is provided at the bottom of the lower mold 2, forming a cavity 25 between the upper mold 1 and the lower mold 2. Since the upper mold 1 can be moved closer to or farther away from the lower mold 2 under the drive of the direct extrusion casting mechanism 4, the direct extrusion casting mechanism 4 drives the upper mold 1 closer to the lower mold 2 to adjust the distance between the upper mold 1 and the lower mold 2, thereby making the distance between the upper mold 1 and the lower mold 2 a filling gap d1, a liquid forging gap d2, or a mold closing gap (fully closed, the gap is zero). The filling gap corresponds to forming a first filling cavity 26, the liquid forging gap corresponds to forming a second filling cavity 27, and the mold closing gap corresponds to forming a part filling cavity 28, as shown in FIG. Figure 6 、 Figure 9 、 Figure 11 shown.

[0105] In one embodiment, the direct extrusion casting mechanism 4 includes an upper driving mechanism 7 and an upper driving push rod 8 . The upper driving mechanism 7 is used to push the upper driving push rod 8 to move, and the upper mold 1 is disposed on the upper driving push rod 8 .

[0106] like Figure 3 As shown, the direct extrusion casting mechanism 4 includes an upper drive mechanism 7 and an upper drive push rod 8. The upper drive mechanism 7 is used to provide a power source for the movement of the upper mold 1 in the vertical direction. Specifically, the upper drive mechanism 7 can adopt a device with linear movement such as an oil cylinder or an electric cylinder. Preferably, the present application adopts an oil cylinder, and the upper drive push rod 8 is connected to the output end of the oil cylinder to realize the movement of the upper drive push rod 8 in the vertical direction. The upper drive push rod 8 is connected to the upper mold base 19 so that the upper drive push rod 8 drives the upper mold base 19 to move, and then drives the upper mold 1 in the vertical direction through the upper mold base 19, so that the gap between the upper mold 1 and the lower mold 2 is a filling gap, a liquid forging gap, and a mold closing gap (the gap is zero).

[0107] In one embodiment, the indirect extrusion casting mechanism 3 includes a lower driving mechanism 9 and a lower driving piston 10, the lower driving mechanism 9 pushes the lower driving piston 10 to move, a lower piston cavity 11 is provided on the lower mold 2, the lower driving piston 10 is slidably disposed in the lower piston cavity 11, and the lower piston cavity 11 is communicated with the mold cavity 25.

[0108] like Figure 3As shown, the indirect extrusion casting mechanism 3 includes a lower drive mechanism 9 and a lower drive piston 10, and the lower drive piston 10 is driven to move by the lower drive mechanism 9. Specifically, a lower piston cavity 11 is provided on the lower mold 2, and a cavity 25 is formed between the upper mold 1 and the lower mold 2. The lower piston cavity 11 is connected to the cavity 25, that is, the lower piston cavity 11 is connected to the first filling cavity 26, the second filling cavity 27, or the part filling cavity 28. Furthermore, the lower piston cavity 11 acts as a barrel for storing molten metal. Therefore, the movement of the lower drive piston 10 within the piston cavity can hydraulically inject the metal in the lower piston cavity 11 into the first filling cavity 26, the second filling cavity 27, or the part filling cavity 28, thereby facilitating extrusion casting.

[0109] In one embodiment, the present invention further includes a feeding mechanism 12, which is arranged on the upper mold 1. The upper mold 1 is provided with a feeding cavity 13. The feeding mechanism 12 is provided with a feeding piston 14. The feeding piston 14 is slidably arranged in the feeding cavity 13. The feeding cavity 13 is connected to the mold cavity 25.

[0110] like Figure 4As shown, the squeeze casting apparatus of the present application further includes a feeding mechanism 12, which includes a feeding cavity 13, a feeding piston 14, and a feeding drive mechanism 21. The feeding drive mechanism 21 utilizes a feeding cylinder, which, through the output end of the feeding cylinder, drives the feeding piston 14 to slide within the feeding cavity 13. Pressure-maintaining feeding is achieved through the movement of the feeding piston 14 within the feeding cavity 13. Liquid metal within the mold cavity 25 is transported to the feeding cavity 13 of the feeding mechanism 12 through the feeding runner 22 under the action of the indirect squeeze casting mechanism 3 and the direct squeeze casting mechanism 4, where it serves as a feeding barrel. When pressure maintenance and feeding are required, the feeding drive mechanism 21 drives the feeding piston 14 to move within the feeding cavity 13, allowing the molten metal in the feeding cavity 13 to be filled into the second filling cavity 27, thereby achieving pressure maintenance and feeding on one side of the second filling cavity. Furthermore, multiple feeding mechanisms 12 can be provided, and these multiple feeding mechanisms 12 can be distributed at different locations on the upper mold 1, such as at both ends of the upper mold 1. The feeding cavities 13 of the multiple feeding mechanisms 12 are connected to the mold cavity 25 via the feeding runner 22, allowing simultaneous pressure maintenance and feeding by multiple feeding mechanisms 12. Simultaneously, the lower driving mechanism 9 of the indirect extrusion casting mechanism 3 drives the lower driving piston 10 to move within the lower piston cavity 11, achieving pressure maintenance and feeding on the other side of the second filling cavity 27. Therefore, through the coordination of the indirect extrusion casting mechanism 3 and the feeding mechanism 12, multi-end pressure maintenance and feeding of the second filling cavity 27 can be achieved, thereby improving casting quality. In addition, a water-sealing baffle 23 and a slag ladle 24 are provided near the feeding mechanism 12. The water-sealing baffle 23 prevents the leakage and splashing of molten metal when the mold is not fully closed; the molten metal in the second filling cavity 27 is transported to the feeding cavity 13 through the direct extrusion casting mechanism 4 and the indirect extrusion casting mechanism 3, and the excess molten metal is transported to the slag ladle 24.

[0111] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0112] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A squeeze casting method, characterized in that: The method comprises: The upper mold is moved downward by the direct extrusion casting mechanism at a first preset speed so that the cavity between the upper mold and the lower mold forms a first filling cavity, and the molten metal is filled into the first filling cavity at a second preset speed by the indirect extrusion casting mechanism; The upper mold is moved downward by the direct extrusion casting mechanism at a third preset speed to perform direct extrusion casting, and at the same time, the cavity between the upper mold and the lower mold is filled with molten metal by the indirect extrusion casting mechanism at a fourth preset speed to switch from the first filling cavity to the second filling cavity; Filling the second filling cavity with molten metal by the indirect extrusion casting mechanism, and moving the upper mold by the direct extrusion casting mechanism to perform direct extrusion casting, so as to switch from the second filling cavity to the part filling cavity; The first preset speed is greater than the third preset speed, and the second preset speed is greater than the fourth preset speed.

2. The squeeze casting method according to claim 1, wherein: The method of moving the upper mold downward by the direct extrusion casting mechanism so that the cavity between the upper mold and the lower mold forms a first filling cavity, and filling the first filling cavity with molten metal by the indirect extrusion casting mechanism, comprises: Moving the upper mold downward at a first preset speed by the direct extrusion casting mechanism so that a gap between the upper mold and the lower mold becomes a filling gap to form the first filling cavity; Filling the molten metal into the first filling cavity at a second preset speed and a preset volume through the indirect squeeze casting mechanism; The preset volume is a first threshold value of the volume of the cast part.

3. The squeeze casting method according to claim 1, wherein: The method of moving the upper mold downward by the direct extrusion casting mechanism to perform direct extrusion casting, and simultaneously filling the cavity between the upper mold and the lower mold with molten metal by the indirect extrusion casting mechanism to switch from the first filling cavity to the second filling cavity, includes: Moving the upper die downward at a third preset speed by the direct extrusion casting mechanism to perform direct extrusion casting, so that the gap between the upper die and the lower die becomes a liquid forging gap, thereby switching from the first filling cavity to the second filling cavity; At the same time, the molten metal is filled into the cavity between the upper mold and the lower mold at a fourth preset speed through the indirect squeeze casting mechanism; The molten metal in the cavity between the upper mold and the lower mold is transported to the feeding mechanism through the direct extrusion casting mechanism and the indirect extrusion casting mechanism, and the excess molten metal is transported to the slag ladle.

4. The squeeze casting method according to claim 1, wherein: The method of filling the second filling cavity with molten metal by the indirect extrusion casting mechanism and moving the upper mold by the direct extrusion casting mechanism to perform direct extrusion casting so as to switch from the second filling cavity to the part filling cavity includes: Pressurizing and feeding the molten metal in the second filling cavity by an indirect squeeze casting mechanism, and simultaneously pressurizing and feeding the molten metal in the second filling cavity by a feeding mechanism; In response to the solid phase ratio of the molten metal in the second filling cavity reaching a preset solid phase threshold, the upper mold is moved by the direct extrusion casting mechanism so that the gap between the upper mold and the lower mold is the closing gap, so as to switch from the second filling cavity to the part filling cavity.

5. A squeeze casting device for implementing the squeeze casting method according to any one of claims 1 to 4, characterized in that: The device comprises: An upper mold (1) and a lower mold (2), wherein a mold cavity (25) is formed between the upper mold (1) and the lower mold (2), and the mold cavity (25) switches between a first filling mold cavity (26), a second filling mold cavity (27), and a part filling mold cavity (28); An indirect extrusion casting mechanism (3) is used to fill the mold cavity (25) with molten metal by an indirect extrusion casting method to perform indirect extrusion casting; A direct extrusion casting mechanism (4) is used for moving the upper mold (1) to perform direct extrusion casting.

6. The squeeze casting device according to claim 5, characterized in that The upper mold (1) is provided with an upper mold cavity (5), and the lower mold (2) is provided with a lower mold cavity (6). The upper mold (1) is slidably arranged relative to the lower mold (2), and the upper mold cavity (5) and the lower mold cavity (6) form the mold cavity (25).

7. The squeeze casting device according to claim 5, characterized in that The direct extrusion casting mechanism (4) comprises an upper driving mechanism (7) and an upper driving push rod (8); the upper driving mechanism (7) is used to push the upper driving push rod (8) to move; and the upper mold (1) is arranged on the upper driving push rod (8).

8. The squeeze casting device according to claim 5, characterized in that The indirect extrusion casting mechanism (3) comprises a lower driving mechanism (9) and a lower driving piston (10). The lower driving mechanism (9) drives the lower driving piston (10) to move. A lower piston cavity (11) is provided on the lower mold (2). The lower driving piston (10) is slidably arranged in the lower piston cavity (11). The lower piston cavity (11) is communicated with the mold cavity (25).

9. The squeeze casting device according to claim 5, characterized in that The mold further comprises a feeding mechanism (12), wherein the feeding mechanism (12) is arranged on the upper mold (1), a feeding cavity (13) is arranged on the upper mold (1), a feeding piston (14) is arranged on the feeding mechanism (12), and the feeding piston (14) is slidably arranged in the feeding cavity (13), and the feeding cavity (13) is communicated with the mold cavity (25).

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