Method of automatically controlling flow of molten metal to a cooling bed using an electron beam

Abstract

The application discloses a kind of electronic beam automatic control cold bed flow material's method belonging to the technical field of electron beam melting.The scanning track program of presetting figure is downloaded to HCM-PV6810PC / 104 CPU module, and scanning track program is automatically run, and electronic beam deflection scanning signal generation module sends deflection scanning control signal, and in turn through D / A conversion module, power amplifier, drive deflection coil to generate magnetic field to carry out electronic beam deflection scanning, and control the actual motion track of electronic beam in cold bed.The method can reduce the energy at the material opening, greatly reduce manpower, material resources, reduce cost, improve smelting efficiency, and increase the purity.

Description

Technical Field

[0001] This invention relates to the field of electron beam melting technology, and in particular to a method for automatically controlling the flow of material in a cooling bed using an electron beam. Background Technology

[0002] With the development of cutting-edge technologies such as aerospace, atomic energy, and automation, ordinary metallic materials are no longer sufficient to meet the requirements, thus increasing the demand for refractory metals. The demand for high-purity refractory metals is growing, especially for metals and alloys with high melting points and easy oxidation. Vacuum electron beam melting furnaces can provide a highly efficient heat source and a high-vacuum environment. Utilizing the characteristics of high-energy electron beams (tens to hundreds of kilowatts) emitted by electron guns, which can be focused to generate high temperatures and high energy density, the high-energy electron beam is focused on refractory metals such as tungsten, tantalum, niobium, and zirconium, melting them and removing impurities to achieve the purpose of melting and purification. During this melting process, the metal from the high-temperature molten zone needs to be dripped into the cooling bed molten pool, cooled and solidified in the ingot crucible, and then formed into ingots by the ingot pulling mechanism.

[0003] Because the cooling bed has a convex shape, the conventional electron beam's trajectory is rectangular, mirroring point 1 on the cooling bed. The electron beam cannot automatically hit the convex opening. One method is to manually adjust the electron beam's trajectory, changing its deflection angle to move the rectangular trajectory to the convex opening, allowing the molten metal to flow from the opening into the ingot crucible. Another method is to add an electron gun at the convex opening of the cooling bed. Once the molten metal has filled the entire cooling bed, the electron gun is activated, melting the metal at the convex opening, allowing it to flow into the ingot crucible. Both methods increase manpower and material resources, resulting in high costs and low smelting efficiency.

[0004] Therefore, there is a need for an electron beam-controlled cooling bed material flow method to reduce manpower and material resources, lower costs, improve smelting efficiency, and increase purification purity. Summary of the Invention

[0005] The purpose of this invention is to provide a method for automatic control of electron beam flow in a cooling bed, comprising: downloading a preset scanning trajectory program to an HCM-PV6810PC / 104 CPU module, automatically running the scanning trajectory program, and having an electron beam deflection scanning signal generation module issue a deflection scanning control signal, which is sequentially transmitted through a D / A conversion module and a power amplifier to drive a deflection coil to generate a magnetic field for electron beam deflection scanning, thereby controlling the actual movement trajectory of the electron beam in the cooling bed.

[0006] Furthermore, the specific process of writing the program for the preset scanning trajectory of the graphic is as follows:

[0007] The electron beam trajectory is decomposed into two components, X and Y, and discretized. The position of the electron beam trajectory is determined by the coordinates. The parameters and scanning period of the electron beam trajectory are set. The number of points required for the electron beam trajectory is counted. Mathematical functions are called within the scanning period to complete the program writing.

[0008] Furthermore, the protrusion of the electron beam trajectory can be controlled by adjusting the size of the electron beam trajectory, the timing of the protrusion, and the energy density.

[0009] Furthermore, the timing of the electron beam appearance at the protrusion of the electron beam trajectory is set according to the purification time of different materials.

[0010] Furthermore, the method also includes: for the rectangular scanning mode, setting the number of points, the number of rectangular trajectory circles, the rectangular spacing, and the point spacing according to the characteristics of the purified material, the evaporation rate of impurities, and the vaporization temperature; after setting the electron beam trajectory parameters, setting the electron beam power according to the melting and purification process; and then setting the purification time; when melting and purifying materials are required, the electron beam trajectory does not appear at the protrusion, but appears in the cooling bed, scanning the cooling bed for material melting and refining, without scanning the material outlet; after the material melting and purification is completed, according to the set purification time, the electron beam trajectory at the material outlet automatically opens to melt the material at the material outlet, so that the molten metal flows into the ingot crucible; by changing the frequency of the material outlet appearance, the material outlet appears once after the rectangle makes N rectangular movements, reducing the energy at the material outlet and preventing the electron beam from hitting the material outlet.

[0011] The beneficial effects of this invention are as follows:

[0012] The method of this invention can reduce the energy at the feed inlet and automatically time the material flow through the electron beam protrusion trajectory, which greatly reduces manpower and material resources, lowers costs, improves smelting efficiency, and increases purification purity. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of an automated electron beam material handling system.

[0014] Figure 2 This is a schematic diagram of the electron beam trajectory.

[0015] Figure 3 This is a flowchart of an electron beam deflection scanning procedure. Detailed Implementation

[0016] This invention proposes a method for automatic control of material flow in a cooling bed using an electron beam. The invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0017] Figure 1This is a schematic diagram of an automatic electron beam material handling system. The automatic electron beam material handling system consists of an electron gun 1, a first focusing coil 2, a second focusing coil 3, a polarization coil 4, and an ingot crucible 5, arranged from top to bottom. The polarization coil 4 is connected to the polarization control system 6, and the host computer 7 communicates with the polarization control system 6.

[0018] Figure 2 This is a schematic diagram of the electron beam trajectory. Figure 3 The flowchart of the electron beam deflection scanning program shows the overall process of automatic electron beam control of material flow in the cooling bed, which includes: downloading the scanning trajectory program of the preset pattern to the HCM-PV6810PC / 104 CPU module, automatically running the scanning trajectory program, and the electron beam deflection scanning signal generation module sending a deflection scanning control signal, which is then passed through the D / A conversion module and the power amplifier to drive the deflection coil 4 to generate a magnetic field for electron beam deflection scanning, thereby controlling the actual movement trajectory of the electron beam in the cooling bed.

[0019] The specific process of writing the scanning trajectory program for the preset graphic is as follows:

[0020] The electron beam trajectory is decomposed into X and Y components and discretized. The position of the electron beam trajectory is determined by the coordinates. The parameters and scanning period of the electron beam trajectory are set, the number of points required for the electron beam trajectory is calculated, and mathematical functions are called within the scanning period to complete the program. The electron beam scanning program includes convex electron beam trajectory output, electron beam scanning power management software, and supports different types of scanning modes (such as rectangular, convex, and circular scanning) and parameter settings. The program development environment is based on a DOS environment or a DOS-compatible compiler (such as C++), and uses header files such as graphics.h, dos.h, and conio.h. The electron beam trajectory is amplified by the X and Y signals and input to the deflection scanning coil, which controls the coil to generate displacement in the X and Y directions. The resultant motion is the desired actual trajectory.

[0021] The protrusion of the electron beam trajectory is controlled by adjusting the size of the electron beam trajectory, the timing of the protrusion, and the energy density.

[0022] The timing of the electron beam appearance at the protrusion of the electron beam trajectory is set according to the purification time of different materials.

[0023] The program's main functions include:

[0024] 1. Supports convex, rectangular, and circular scanning, including segmented scanning and full circle scanning.

[0025] 2. Provide a user interface that allows users to adjust scanning parameters via keyboard input.

[0026] 3. Save and load the scan parameters to the file (dh_hxl.dat).

[0027] IV. Drawing the scan trajectory and displaying the graphics (using the graphics.h library).

[0028] 5. Control the electron beam scanning via a serial D / A converter.

[0029] In addition, the size of the cooling bed and the material inlet of the electron beam melting furnace are first adjusted through the system's function options to ensure that the entire electron beam trajectory has a certain distance from the cooling bed, preventing the electron beam from hitting the cooling bed and damaging it.

[0030] Based on the characteristics of the purified material, the evaporation rate and vaporization temperature of impurities vary. Parameters such as the number of points, the number of rectangular trajectory loops, the spacing between rectangles, and the point spacing are set. After setting the electron beam trajectory parameters, the electron beam power is set according to the smelting and purification process. After setting the above parameters, the purification time (material melting and refining time in the cooling bed) is set. When smelting and purifying the material, the raised line will not appear, and the electron beam trajectory will appear in the cooling bed but not at the material inlet. At this time, the electron beam will not scan the material inlet; instead, it will scan the cooling bed for material melting and refining. After the material melting and purification are completed, according to the set time, the raised line electron beam trajectory at the material inlet of the cooling bed automatically opens to melt the material, allowing the molten metal to flow into the lower circular crucible. This achieves automatic material flow at set intervals. The frequency of the material inlet appearance can also be adjusted. After the rectangle performs N rectangular movements, the raised material inlet appears once, reducing the energy at the material inlet, protecting it, and preventing the electron beam from repeatedly hitting the material inlet and causing leakage.

[0031] In summary, compared with existing electron beam melting equipment, the automatic control cooling bed material flow system of the present invention greatly reduces manpower and material resources, improves melting efficiency, and increases purification purity.

Claims

1. A method for automatically controlling material flow in a cooling bed using an electron beam, characterized in that, include: The preset scanning trajectory program is downloaded to the HCM-PV6810PC / 104 CPU module. The scanning trajectory program runs automatically. The electron beam deflection scanning signal generation module sends a deflection scanning control signal, which passes through the D / A conversion module and the power amplifier in sequence to drive the deflection coil to generate a magnetic field for electron beam deflection scanning, thereby controlling the actual movement trajectory of the electron beam in the cooling bed.

2. The method for automatic electron beam control of cooling bed material flow according to claim 1, characterized in that, The specific process of writing the program for the scanning trajectory of the preset graphic is as follows: The electron beam trajectory is decomposed into two components, X and Y, and discretized. The position of the electron beam trajectory is determined by the coordinates. The parameters and scanning period of the electron beam trajectory are set. The number of points required for the electron beam trajectory is counted. Mathematical functions are called within the scanning period to complete the program writing.

3. The method for automatic electron beam control of cooling bed material flow according to claim 2, characterized in that, The protrusion of the electron beam trajectory is controlled by adjusting the size of the electron beam trajectory, the timing of the protrusion, and the energy density.

4. The method for automatic electron beam control of cooling bed material flow according to claim 3, characterized in that, The timing of the electron beam appearance at the protrusion of the electron beam trajectory is set according to the purification time of different materials.

5. The method for automatic electron beam control of cooling bed material flow according to claim 4, characterized in that, The method further includes: for the rectangular scanning mode, setting the number of points, the number of rectangular trajectory circles, the rectangular spacing, and the point spacing according to the characteristics of the purified material, the evaporation rate of impurities, and the vaporization temperature; after setting the electron beam trajectory parameters, setting the electron beam power according to the melting and purification process; and then setting the purification time; when melting and purifying materials are required, the electron beam trajectory does not appear at the protrusion, but appears in the cooling bed, scanning the cooling bed for material melting and refining, without scanning the material outlet; after the material melting and purification is completed, according to the set purification time, the electron beam trajectory at the material outlet automatically opens to melt the material at the material outlet, so that the molten metal flows into the ingot crucible; by changing the frequency of the material outlet appearance, the material outlet appears once after the rectangle makes N rectangular movements, reducing the energy at the material outlet and preventing the electron beam from hitting the material outlet.

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