Electromagnetic vibration casting method and device suitable for anti-gravity casting

Abstract

The invention provides an electromagnetic vibration casting method and device suitable for anti-gravity casting, and the method comprises the steps: putting a high-temperature alloy raw material into a crucible, and putting the crucible into a smelting furnace; vacuumizing an upper cavity and a lower cavity of the smelting furnace, and then melting the high-temperature alloy raw material into a high-temperature alloy melt according to a casting process; a shell is installed in the upper cavity, a riser tube is installed in the lower cavity, the lower end of the riser tube is immersed in the high-temperature alloy melt, and the upper end of the riser tube extends into the upper cavity and is connected with the shell; after mold filling is completed, in the solidification process, vibrating electromagnetic pressure is applied to the high-temperature alloy melt in the riser tube; and after the casting is solidified completely, the upper cavity and the lower cavity are subjected to pressure relief, and the target casting is obtained. The melt feeding capacity can be improved, and then the service performance of a casting is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of counter-gravity casting, and in particular to an electromagnetic vibration casting method and device suitable for counter-gravity casting. Background Art

[0002] Large, complex castings suffer from slow cooling rates, wide mushy zones, and difficulty feeding shrinkage, resulting in coarse grains and numerous loose defects, leading to insufficient mechanical properties and service life. Applying an external field to the melt during filling and solidification to promote the breakup of initially formed grains can effectively increase the nucleation base in the melt, thereby refining the grains and improving the mechanical properties of the casting. This method has been widely used in conventional gravity casting, for example by rotating the mold shell or applying mechanical or ultrasonic vibration to the shell.

[0003] Counter-gravity casting is a casting process that uses external pressure as the filling power to inject the alloy liquid upward into the mold along the riser tube. The filling process is highly dynamic and the melt flow is controllable, so it has good molding capabilities for complex thin-walled castings. In counter-gravity precision casting, the ceramic shell is placed in the upper chamber, and the lower end is tightly connected to the riser tube as a whole. The lower end of the riser tube is immersed in the melt in the crucible; to ensure airtightness, the riser tube is tightly connected to the middle partition where the upper and lower chambers meet to achieve sealing. Therefore, the relative positions of the ceramic shell and the riser tube are fixed, making it difficult to place the shell on a mechanical vibration table to apply vibration or rotate the shell as in traditional gravity casting. As a result, traditional mechanical vibration and rotation are difficult to apply in the counter-gravity precision process.

[0004] A search revealed patent application number CN119035503A, which discloses a method for improving the uniformity and grain-refining effect of a grain refiner. The method includes the following steps: adding a predetermined amount of grain refiner to the molten metal prior to mold filling and subjecting it to electromagnetic stirring. The alloy melt is then filled at the specified temperature, solidified under pressure, maintained under pressure, fed back, and then released to remove the product. This patent applies electromagnetic stirring to the melt in the crucible to promote melt flow and uniformly disperse the grain refiner throughout the melt.

[0005] The patent application publication number CN109434077A discloses a vacuum casting forming device and gas path system based on an electromagnetic field. The electromagnetic field generated by the electromagnetic field generating device acts on the molten metal in the vacuum differential pressure casting device. The stirring action of the electromagnetic field makes the grain size of the vacuum differential pressure casting alloy structure more refined, the internal chemical composition is uniform, the dendrite segregation is reduced, and the casting defects are further improved. At the same time, the mechanical properties of the alloy are significantly improved, the fatigue resistance is enhanced, and the forming quality of the casting is improved. The patent adds an electromagnetic field generating device to the periphery of the upper chamber casting mold. After the alloy melt is filled with anti-gravity, the electromagnetic field generating device generates a magnetic field to stir the melt in the casting mold, forcing the melt to flow and the dendrites to break up, thereby achieving the purpose of refining the grains. In this patent, the electromagnetic field acts on the outer surface of the mold shell, with the purpose of applying a stirring force to the melt to break up the dendrites. Summary of the Invention

[0006] In view of the defects in the prior art, the purpose of the present invention is to provide an electromagnetic vibration casting method and device suitable for counter-gravity casting.

[0007] According to one aspect of the present invention, there is provided an electromagnetic vibration casting method suitable for counter-gravity casting, comprising:

[0008] Putting a high-temperature alloy raw material into a crucible, and placing the crucible in a melting furnace;

[0009] The upper chamber and the lower chamber of the smelting furnace are both evacuated to a vacuum state, and then the high-temperature alloy raw material is melted into a high-temperature alloy melt according to a casting process;

[0010] Installing a mold shell in the upper chamber and installing a riser pipe in the lower chamber, wherein the lower end of the riser pipe is immersed in the high-temperature alloy melt and the upper end extends into the upper chamber and is connected to the mold shell;

[0011] After the mold filling is completed, during the solidification process, a vibrating electromagnetic pressure is applied to the high-temperature alloy melt in the riser tube;

[0012] After the casting is completely solidified, the pressure in the upper chamber and the lower chamber is released to obtain the target casting.

[0013] Optionally, during the solidification process, a vibrating electromagnetic pressure is applied to the high-temperature alloy melt in the riser tube, wherein an electromagnetic pump is used as the vibration source.

[0014] Optionally, the electromagnetic pressure of the electromagnetic pump is adjusted by an electromagnetic pump controller.

[0015] Optionally, during the solidification process, vibrating electromagnetic pressure is applied to the high-temperature alloy melt in the riser tube, wherein the pressure amplitude and frequency of the vibrating electromagnetic pressure are determined according to the requirements of the counter-gravity casting process.

[0016] Optionally, during the solidification process, vibrating electromagnetic pressure is applied to the high-temperature alloy melt in the riser tube, wherein the time for applying the vibrating electromagnetic pressure is the same as the solidification time.

[0017] Optionally, the method further includes: during the mold filling process, adjusting the gas pressures of the upper chamber and the lower chamber to form a pressure difference and push the high-temperature alloy melt into the mold cavity.

[0018] According to another aspect of the present invention, there is provided an electromagnetic vibration casting device suitable for counter-gravity casting, for implementing the above-mentioned electromagnetic vibration casting method suitable for counter-gravity casting, the device comprising:

[0019] a lower chamber, wherein a crucible is placed in the lower chamber, and the crucible is used for melting high-temperature alloy raw materials;

[0020] an upper chamber, wherein the mold shell is arranged in the upper chamber;

[0021] a middle partition, provided between the upper chamber and the lower chamber;

[0022] a riser pipe, the riser pipe passing through the middle partition plate, one end of the riser pipe being immersed in the crucible and the other end being connected to the gate of the mold shell;

[0023] The electromagnetic control device is used to apply vibrating electromagnetic pressure to the high-temperature alloy melt in the riser tube during the solidification process.

[0024] Optionally, the electromagnetic control device includes an electromagnetic pump and an electromagnetic pump controller connected to the electromagnetic pump, the electromagnetic pump is arranged in the lower chamber, and the electromagnetic pump controller is used to adjust the electromagnetic pressure of the electromagnetic pump.

[0025] Optionally, the electromagnetic pump is located near the top of the lower chamber.

[0026] Optionally, it further includes an air pressure control device, which is used to adjust the gas pressure of the upper chamber and the lower chamber during the filling process to form a pressure difference and push the high-temperature alloy melt into the mold cavity.

[0027] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0028] The method provided by the present invention applies vibrating electromagnetic pressure to the high-temperature alloy melt in the riser during the solidification process, and transmits the vibrating electromagnetic pressure to various parts of the casting mold through the melt, thereby achieving the purpose of breaking dendrites and refining grains, and can improve the melt shrinkage feeding capacity, thereby improving the service performance of the casting. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0030] Figure 1 Schematic diagram of the structure of an electromagnetic vibration casting device suitable for counter-gravity casting in one embodiment of the present invention.

[0031] In the figure: 1 is a crucible, 2 is a lower chamber, 3 is a mold shell, 4 is an upper chamber, 5 is a riser, 6 is a middle partition, 7 is an air pressure regulating control mechanism, 8 is an air outlet channel of the lower chamber, 9 is an air inlet channel of the lower chamber, 10 is an air inlet channel of the upper chamber, 11 is an air outlet channel of the upper chamber, 12 is an electromagnetic pump, and 13 is an electromagnetic pump controller. DETAILED DESCRIPTION

[0032] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several variations and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0033] Existing mechanical vibration or rotation methods are not suitable for counter-gravity casting. The purpose of the embodiments of the present invention is to propose an electromagnetic vibration casting method suitable for counter-gravity casting to refine the grain size and improve the mechanical properties of the casting.

[0034] An electromagnetic vibration casting method suitable for counter-gravity casting provided by one embodiment of the present invention includes the following steps:

[0035] Step S1: placing a high-temperature alloy raw material in a crucible, and placing the crucible in a melting furnace;

[0036] Step S2: evacuating the upper chamber and the lower chamber of the melting furnace, and then melting the high-temperature alloy raw material into a high-temperature alloy melt according to the casting process;

[0037] Step S3: Install the mold shell in the upper chamber and the riser tube in the lower chamber, with the lower end of the riser tube immersed in the high-temperature alloy melt and the upper end extending into the upper chamber and connected to the mold shell;

[0038] Step S4: After the mold filling is completed, during the solidification process, a vibrating electromagnetic pressure is applied to the high-temperature alloy melt in the riser tube;

[0039] Step S5: After the casting is completely solidified, the upper chamber and the lower chamber are depressurized to obtain the target casting.

[0040] Specifically, the oscillating electromagnetic pressure indicates that the electromagnetic pressure fluctuates. The magnitude of the electromagnetic pressure is closely related to the magnitude of the current passing through it. By periodically changing the magnitude of the current, the frequency of the oscillating pressure can be controlled.

[0041] The present invention applies high-frequency vibration pressure to the high-temperature alloy melt in the riser tube. The melt transmits the vibration pressure to various parts of the mold, subjecting the melt to vibration pressure during solidification. This achieves the purpose of breaking up dendrites and refining grains. Extrusion promotes melt feeding and flow into loose pores, resulting in a dense casting. This improves melt feeding capacity and, consequently, the serviceability of the casting.

[0042] Compared to the prior art applications with publication numbers CN119035503A and CN109434077A, the electromagnetic pressure in the embodiments of the present invention acts on the riser tube, applying vertical vibrating pressure to the high-temperature alloy melt in the riser tube, and transmitting the vibrating electromagnetic pressure to various parts of the casting mold through the melt. However, the aforementioned comparative document CN119035503A applies electromagnetic force to the melting crucible, utilizing the stirring effect of electromagnetic force to promote the rotational flow of the melt in the crucible, thereby achieving the purpose of uniformly dispersing the grain refiner in the melt. The comparative document CN109434077A surrounds the electromagnetic coil around the outside of the mold shell, and the electromagnetic stirring effect generated by the coil directly acts on the casting. The embodiments of the present invention apply an electromagnetic pump to the riser tube, applying vibrating pressure to the melt in the riser tube, and using the liquid melt to transmit the pressure to various parts of the casting, which is different from the electromagnetic action location and principle of the aforementioned prior art.

[0043] In the above embodiment of the present invention, during the mold filling process before step S4, the gas pressures in the upper chamber and the lower chamber are adjusted to form a pressure difference, thereby pushing the high-temperature alloy melt into the mold cavity.

[0044] To apply vibratory electromagnetic pressure to the high-temperature alloy melt in the riser tube during solidification, in some embodiments, an electromagnetic pump is used as the vibration source in step S4. This utilizes the electromagnetic pump's ability to transport conductive liquids, allowing for adjustable force, thereby generating a periodic force that applies vibratory pressure to the melt. By aligning the pump's melt outlet with the riser tube axis and adjusting the current parameters, vertical vibratory pressure can be applied to the high-temperature alloy melt in the riser tube.

[0045] In the above-described embodiments of the present application, an electromagnetic pump is used to adjust the electromagnetic pressure amplitude by controlling the current flowing through the electromagnetic pump. Adjusting the current according to a certain periodic pattern can achieve frequency variation of the pressure. It should be noted that appropriately increasing the frequency can increase the number of pressure fluctuations in the alloy melt, which is beneficial for dendrite breakage.

[0046] In order to achieve regulation and control of the electromagnetic pressure, in some further embodiments, the electromagnetic pressure of the electromagnetic pump is regulated by an electromagnetic pump controller.

[0047] Specifically, the pressure is determined by the melt's density, temperature, and viscosity, the casting's height and shape complexity, and the required holding pressure. The vibration frequency also needs to be tailored to the specific casting structure, material properties, and requirements. Adjusting the electromagnetic pressure is achieved by adjusting the electromagnetic pump's current and frequency.

[0048] The above embodiment of the present invention uses an electromagnetic pump as the vibration source and is controlled by an electromagnetic pump controller. This allows for precise control of the vibration frequency and amplitude, resulting in high control accuracy. The amplitude and frequency of the electromagnetic pressure are determined based on the requirements of the counter-gravity casting process.

[0049] To enhance the feeding effect, in some embodiments, vibrating electromagnetic pressure is applied throughout the entire solidification process, i.e., the duration of the application is the same as the solidification time. Applying vibrating electromagnetic pressure throughout the solidification process provides a longer-term and more extensive feeding and grain-refining effect on the entire casting, effectively enhancing grain refinement.

[0050] Based on the same concept, another embodiment of the present invention provides an electromagnetic vibration casting device suitable for anti-gravity casting, which is used to implement the above-mentioned electromagnetic vibration casting method suitable for anti-gravity casting, referring to Figure 1 As shown, the device includes an upper chamber 4, a lower chamber 2, a crucible 1, a riser tube 5, a mold shell 3, a middle partition 6, an electromagnetic control device, etc., wherein the crucible 1 is placed in the lower chamber 2, and the crucible 1 is used to melt high-temperature alloy raw materials; the mold shell 3 is arranged in the upper chamber 4; the middle partition 6 is arranged between the upper chamber 4 and the lower chamber 2; the riser tube 5 passes through the middle partition 6, and one end of the hollow riser tube 5 is immersed in the crucible 1, and the other end is tightly connected with the gate of the mold shell 3; the electromagnetic control device is used to apply vibrating electromagnetic pressure to the high-temperature alloy melt in the riser tube 5 during the solidification process.

[0051] In some embodiments, the electromagnetic control device includes an electromagnetic pump 12 and an electromagnetic pump controller 13 connected to the electromagnetic pump 12 . The electromagnetic pump 12 is disposed in the lower chamber 2 . The electromagnetic pump controller 13 is used to adjust the electromagnetic pressure of the electromagnetic pump 12 .

[0052] In some embodiments, the electromagnetic pump 12 is located near the top of the lower chamber 2 .

[0053] In the above embodiment of the present application, the electromagnetic pump 12 is positioned as close to the middle partition 6 as possible. On the one hand, this can reduce the pressure loss caused by overcoming the gravity of the melt, and on the other hand, it can be away from the high-temperature heat source of the melting crucible 1 to protect the pump body.

[0054] The casting device in the above embodiment also includes an air pressure control device, which is used to adjust the gas pressure in the upper chamber and the lower chamber during the filling process to form a pressure difference and push the high-temperature alloy melt into the mold cavity.

[0055] Exemplarily, the air pressure control device includes an air pressure regulating control mechanism 7 and an upper chamber air inlet channel 10, an upper chamber air outlet channel 11, a lower chamber air inlet channel 9 and a lower chamber air outlet channel 8 respectively connected to the air pressure regulating control mechanism 7.

[0056] During the filling process, the air pressure regulating and controlling mechanism 7 fills the upper and lower chambers with gas through various gas channels as required, so that the air pressure in the lower chamber is greater than that in the upper chamber. A pressure difference is formed according to the set procedure, forcing the high-temperature alloy melt to enter the mold shell 3 from bottom to top along the riser tube 5, completing the filling process; then the air pressure in the lower chamber continues to be increased and maintained for solidification.

[0057] During the pressure-maintaining solidification process, the electromagnetic pump 12 applies vibrating electromagnetic pressure to the high-temperature alloy melt in the riser 5. The operation of the electromagnetic pump 12 is regulated by the electromagnetic pump controller 13, forcing the melt to solidify under the action of the vibrating electromagnetic pressure. The melt in various parts of the mold shell 3 can be forced to vibrate, achieving the purpose of flushing and refining the grains, thereby improving the strength and fatigue life of the casting.

[0058] In a specific application example, the anti-gravity electromagnetic vibration casting device in the above embodiment is used to perform anti-gravity casting of high-temperature alloy castings. The specific steps are as follows:

[0059] Put enough high-temperature alloy raw material into the crucible 1, and place the crucible 1 at a designated position in the melting furnace;

[0060] The airflow is controlled by a pressure control mechanism, and both the upper and lower chambers are evacuated to 5 Pa. Then, the raw materials in the crucible 1 are melted to the target temperature according to the high-temperature alloy melting process;

[0061] Place the mold shell 3 and the riser tube 5 in designated positions so that the lower end of the riser tube 5 is immersed in the high-temperature alloy melt and the upper end is tightly connected to the mold shell 3;

[0062] The pressure in the upper and lower chambers is adjusted by the air pressure control mechanism so that the pressure in the upper and lower chambers is executed according to the preset pressure control scheme.

[0063] During the pressure holding stage, the upper chamber pressure is maintained at 50 kPa, and the lower chamber pressure is maintained at 150 kPa. The pressure control scheme of the electromagnetic pump 12 is set by the electromagnetic pump controller 13, with a pressure amplitude of 25 kPa, a frequency of 1 Hz, and a vibration time of 10 minutes. Vibration pressure is applied to the melt through the electromagnetic pump 12.

[0064] After maintaining the pressure for 10 minutes, the upper and lower chambers are depressurized, the mold is taken out, and the target casting is obtained.

[0065] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various modifications or variations within the scope of the claims without affecting the essence of the present invention. The above preferred features may be used in any combination as long as they do not conflict with each other.

Claims

1. An electromagnetic vibration casting method suitable for anti-gravity casting, characterized in that: include: Putting a high-temperature alloy raw material into a crucible, and placing the crucible in a melting furnace; The upper chamber and the lower chamber of the smelting furnace are both evacuated to a vacuum state, and then the high-temperature alloy raw material is melted into a high-temperature alloy melt according to a casting process; Installing a mold shell in the upper chamber and installing a riser pipe in the lower chamber, wherein the lower end of the riser pipe is immersed in the high-temperature alloy melt and the upper end extends into the upper chamber and is connected to the mold shell; After the mold filling is completed, during the solidification process, a vibrating electromagnetic pressure is applied to the high-temperature alloy melt in the riser tube; After the casting is completely solidified, the pressure in the upper chamber and the lower chamber is released to obtain the target casting.

2. The electromagnetic vibration casting method suitable for counter-gravity casting according to claim 1, characterized in that: During the solidification process, a vibrating electromagnetic pressure is applied to the high-temperature alloy melt in the riser tube, wherein an electromagnetic pump is used as a vibration source.

3. The electromagnetic vibration casting method suitable for counter-gravity casting according to claim 2, characterized in that: The electromagnetic pressure of the electromagnetic pump is adjusted by an electromagnetic pump controller.

4. The electromagnetic vibration casting method suitable for counter-gravity casting according to claim 1, characterized in that: During the solidification process, vibrating electromagnetic pressure is applied to the high-temperature alloy melt in the riser tube, wherein the pressure amplitude and frequency of the vibrating electromagnetic pressure are determined according to the requirements of the counter-gravity casting process.

5. The electromagnetic vibration casting method suitable for counter-gravity casting according to claim 1, characterized in that: During the solidification process, a vibrating electromagnetic pressure is applied to the high-temperature alloy melt in the riser tube, wherein the time for applying the vibrating electromagnetic pressure is the same as the solidification time.

6. The electromagnetic vibration casting method suitable for counter-gravity casting according to claim 1, characterized in that: Also includes: During the mold filling process, the gas pressures in the upper chamber and the lower chamber are adjusted to form a pressure difference, thereby pushing the high-temperature alloy melt into the mold cavity.

7. An electromagnetic vibration casting device suitable for counter-gravity casting, used to implement the electromagnetic vibration casting method suitable for counter-gravity casting according to any one of claims 1 to 6, characterized in that: The device comprises: a lower chamber, wherein a crucible is placed in the lower chamber, and the crucible is used for melting high-temperature alloy raw materials; an upper chamber, wherein the mold shell is arranged in the upper chamber; a middle partition, provided between the upper chamber and the lower chamber; a riser pipe, the riser pipe passing through the middle partition plate, one end of the riser pipe being immersed in the crucible and the other end being connected to the gate of the mold shell; The electromagnetic control device is used to apply vibrating electromagnetic pressure to the high-temperature alloy melt in the riser tube during the solidification process.

8. The electromagnetic vibration casting device suitable for counter-gravity casting according to claim 7, characterized in that: The electromagnetic control device includes an electromagnetic pump and an electromagnetic pump controller connected to the electromagnetic pump. The electromagnetic pump is arranged in the lower chamber. The electromagnetic pump controller is used to adjust the electromagnetic pressure of the electromagnetic pump.

9. The electromagnetic vibration casting device suitable for counter-gravity casting according to claim 8, characterized in that: The electromagnetic pump is located in the lower chamber near the top.

10. The electromagnetic vibration casting device suitable for counter-gravity casting according to claim 7, characterized in that: It also includes an air pressure control device, which is used to adjust the gas pressure of the upper chamber and the lower chamber during the filling process to form a pressure difference and push the high-temperature alloy melt into the mold cavity.

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