A method for electron beam additive manufacturing of nickel-based superalloys

Abstract

This invention discloses a method for forming nickel-based superalloys using electron beam additive manufacturing, belonging to the field of electron beam additive manufacturing technology, and is used to solve the problem of cracking that easily occurs in existing electron beam additive manufacturing of nickel-based superalloys. The method includes: designing a three-dimensional model of the part using software; importing the three-dimensional model of the part into a software platform to repair the model; placing the repaired model on a printing platform; after completing the model repair and placement, exporting the model as an STL format file and importing it into a printing device; preheating the substrate; forming the core region and contour region of the part separately with an electron beam, printing to obtain an initial part, and then performing hot isostatic pressing to obtain the final part; in step 4, the scanning beam current of the electron beam forming the contour region of the part is less than the scanning beam current of the electron beam forming the core region of the part, and the scanning rate of the electron beam forming the contour region of the part is greater than the scanning rate of the electron beam forming the core region of the part. The nickel-based superalloy formed by this invention is crack-free.

Description

Technical Field

[0001] This invention relates to the field of electron beam additive manufacturing technology, and in particular to a method for forming nickel-based superalloys using electron beam additive manufacturing. Background Technology

[0002] Additive manufacturing is a rapid manufacturing technology with the greatest development potential, enabling the efficient production of complex alloy parts that are difficult to machine or cast using conventional methods. However, due to the large particle size distribution and printing thickness of the powder used in electron beam additive manufacturing, the surfaces of parts printed using this technology often exhibit large "pseudo-sintered" particles. These areas are prone to crack formation and propagation into the printed part, ultimately leading to failure. This is especially true for refractory and difficult-to-machine nickel-based superalloys, where microcracks easily form within the printed part during electron beam additive manufacturing, affecting internal quality. Therefore, optimizing methods for forming nickel-based superalloys using electron beam additive manufacturing to control crack formation is of great significance. Summary of the Invention

[0003] In view of the above, the present invention aims to provide a method for electron beam additive manufacturing of nickel-based superalloys to solve the problem of cracking that easily occurs in the existing electron beam additive manufacturing of nickel-based superalloys.

[0004] The objective of this invention is mainly achieved through the following technical solutions:

[0005] This invention provides a method for electron beam additive manufacturing of nickel-based superalloys, comprising the following steps:

[0006] Step 1: Design a 3D model of the part using software;

[0007] Step 2: Import the 3D model of the part into the Magics software platform to repair the model. Place the repaired model on the printing platform. After completing the repair and placement of the model, export the model as an STL file and import the STL file into the printing device.

[0008] Step 3: Preheat the substrate;

[0009] Step 4: The electron beam shapes the core area and contour area of ​​the part respectively, and prints the initial part;

[0010] Step 5: Perform hot isostatic pressing on the initial part to obtain the final part;

[0011] In step 4, the scanning beam current I2 of the electron beam forming part contour region is less than the scanning beam current I1 of the electron beam forming part core region, and the scanning rate V2 of the electron beam forming part contour region is greater than the scanning rate V1 of the electron beam forming part core region.

[0012] Furthermore, in step 3, the temperature of the preheated substrate is 850℃~1200℃.

[0013] Furthermore, in step 4, the printing process employs block-based non-continuous scanning.

[0014] Furthermore, in step 4, the blocks are one of 0.5*3mm, 1*3mm, 3*3mm, 5*5mm, and 7*7mm.

[0015] Furthermore, in step 4, the number of contour regions is 2 to 3.

[0016] Furthermore, in step 4, the energy thermal input E of the core region of the electron beam forming part satisfies:

[0017] E = (I1 × U1) / (V1 × H1 × L1);

[0018] Where E represents the energy thermal input of the core region of the electron beam formed part, in J / mm³.

[0019] I1 represents the scanning beam current in the core region of the electron beam shaped part, in mA.

[0020] U1 is the accelerating voltage (V) in the core region of the electron beam forming part.

[0021] V1 is the scanning rate of the core region of the electron beam-formed part, in mm / s.

[0022] H1 represents the layer thickness of the core region of the electron beam formed part, in mm.

[0023] L1 is the scanning line spacing of the core area of ​​the electron beam forming part, in mm.

[0024] Further, in step 4, the scanning beam current I1 of the core region of the electron beam forming component is 10mA to 30mA, the accelerating voltage U1 of the core region of the electron beam forming component is 60000V, the scanning rate V1 of the core region of the electron beam forming component is 10mm / s to 27mm / s, the layer thickness H1 of the core region of the electron beam forming component is 0.05mm to 1mm, and the scanning line spacing L1 of the core region of the electron beam forming component is 0.5mm to 1mm.

[0025] Further, in step 4, the scanning beam current I2 of the electron beam forming part contour region is 5mA to 15mA, the accelerating voltage U2 of the electron beam forming part contour region is 60000V, the scanning rate V2 of the electron beam forming part contour region is 50mm / s to 70mm / s, the layer thickness H2 of the electron beam forming part core region is 0.05mm to 1mm, and the spacing L2 between adjacent scanning contours during electron beam forming of the contour region is 0.1mm to 0.15mm.

[0026] Furthermore, in step 5, the hot isostatic pressing temperature is 900℃~1200℃, and the hot isostatic pressing pressure is 120MPa~160MPa.

[0027] Furthermore, in step 5, the hot isostatic pressing and heat preservation time is 3h to 5h.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. The method for electron beam additive manufacturing of nickel-based superalloys of the present invention reduces the internal stress generated during the printing process and lowers the risk of crack defects in the superalloy sample by using segmented discontinuous scanning instead of continuous scanning and precisely controlling the process parameters.

[0030] 2. The method for electron beam additive manufacturing of nickel-based superalloys of the present invention, by precisely controlling the process parameters in the core region and contour region of the electron beam forming process, ensures that the density, performance and surface quality of the part meet the requirements, while reducing the risk of crack defects in the superalloy sample.

[0031] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of what is particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0032] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0033] Figure 1 This is a schematic diagram of the three-dimensional model of the K438 tapered component in Example 1;

[0034] Figure 2 This is a schematic diagram of a three-dimensional model of the CM247LC cuboid component in Example 2;

[0035] Figure 3 This is a schematic diagram of the core region and contour region of any scanning layer during the forming of nickel-based high-temperature alloy parts according to the present invention.

[0036] Reference numerals: 1-Core region; 2-Contour region; 3-Heat-affected zone between the contour region and the core region. Detailed Implementation

[0037] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of the present invention and, together with the embodiments of the present invention, serve to illustrate the principles of the present invention.

[0038] Through long-term in-depth research, the inventors discovered that when electron beam additive manufacturing forms nickel-based superalloys, the core region requires sintering with higher energy input process parameters to ensure the density of the core solid, while the contour region requires sintering with a certain energy for rapid scanning to ensure that the surface quality of the part meets technical requirements (e.g., surface roughness Ra not exceeding 12.5 μm). Therefore, using the same process parameters when forming the core and contour regions can easily lead to cracking.

[0039] This invention provides a method for electron beam additive manufacturing of nickel-based superalloys, comprising:

[0040] Step 1: Design a 3D model of the part using software;

[0041] Step 2: Import the 3D model of the part into the Magics software platform to repair the model. Place the repaired model on the printing platform. After completing the repair and placement of the model, export the model as an STL file and import the STL file into the printing device.

[0042] Step 3: Preheat the substrate;

[0043] Step 4: The electron beam shapes the core area and contour area of ​​the part respectively, and prints the initial part;

[0044] Step 5: Perform hot isostatic pressing on the initial part to obtain the final part.

[0045] In step 4, the scanning beam current I2 of the electron beam forming part contour region is less than the scanning beam current I1 of the electron beam forming part core region, and the scanning rate V2 of the electron beam forming part contour region is greater than the scanning rate V1 of the electron beam forming part core region.

[0046] Specifically, in step 3 above, to ensure stable forming of the high-temperature alloy and reduce the internal stress generated by electron beam printing, the substrate can be preheated. However, considering that excessively high substrate temperatures can damage the equipment due to heat radiation, increasing equipment requirements and development costs, and that excessively high substrate temperatures consume ineffective energy while excessively low temperatures can easily lead to "powder blowing" (powder splashing that cannot be used in the printed parts or samples, resulting in waste) during the electron beam forming process, poor bonding between the printed parts and the substrate, and quality problems, the substrate is preheated to 850℃~1200℃.

[0047] Specifically, the core region in step 4 above refers to all regions outside the boundary of a certain scanned layer of the part. This region ensures that the part's density meets the requirements and determines the part's performance (for example, such as...). Figure 3 (The position of the middle finger).

[0048] Specifically, the contour region in step 4 above is the boundary of a certain scanning layer of the part. This region ensures that the surface quality of the part meets the requirements, determining that the surface roughness of the part is ≤12.5μm. Figure 3 (The position of the middle finger ②);

[0049] In practice, the boundary region of a certain scanning layer that can achieve a surface roughness of 12.5μm for the part is defined as the contour region, and all regions of the current scanning layer other than the contour region are the core regions.

[0050] Specifically, in step 4 above, the energy thermal input E needs to be considered during the electron beam shaping of the core region:

[0051] E = (I1 × U1) / (V1 × H1 × L1);

[0052] Where E is the energy heat input, J / mm 3 ,

[0053] I1 is the scanning beam current, mA.

[0054] U1 is the accelerating voltage, V.

[0055] V1 is the scan rate, in mm / s.

[0056] H1 is the layer thickness, in mm.

[0057] L1 is the scan line spacing, in mm.

[0058] E is the result of comprehensive calculations based on scanning beam current, accelerating voltage, scanning rate, layer thickness, and scanning line spacing. Considering that excessive energy heat input E will cause the part to overheat (blacken), while insufficient E will result in poor sintering, the scanning beam current I1 in the core region of electron beam forming is controlled at 10mA–30mA, accelerating voltage U1 at 60000V, scanning rate V1 at 10mm / s–27mm / s, layer thickness H1 at 0.05mm–1mm, and scanning line spacing L1 at 0.5mm–1mm. Therefore, the energy heat input E for controlling the core region of electron beam forming is 22.22J / mm². 3 ~7200J / mm 3 .

[0059] Meanwhile, to ensure that the surface quality of the part meets the requirements (surface roughness Ra≤12.5μm), the scanning beam current I2 of the electron beam formed part contour region is less than the scanning beam current I1 of the electron beam formed part core region, and the scanning rate V2 of the electron beam formed part contour region is greater than the scanning rate V1 of the electron beam formed part core region; wherein, the scanning beam current I2 of the electron beam formed part contour region is 5~15mA, the scanning rate V2 of the electron beam formed part contour region is 50~70mm / s, the accelerating voltage U2 is 60000V, and the layer thickness H2 is 0.05mm-1mm;

[0060] Specifically, in step 4 above, to improve internal quality and reduce internal stress, segmented discontinuous scanning is used instead of continuous scanning. The segment size can be one of 0.5*3mm, 1*3mm, 3*3mm, 5*5mm, or 7*7mm; when the area of ​​the scanned layer is less than 5*5mm, segments of 0.5*3mm, 1*3mm, or 3*3mm are selected. When the area of ​​the scanned layer is greater than or equal to 5*5mm, segments of 5*5mm or 7*7mm are selected.

[0061] Specifically, in step 4 above, in electron beam additive manufacturing, the number of contours represents the number of times the part boundary is scanned. Considering that too many contours result in better part surface quality but lower forming efficiency, while too few contours result in poorer part surface quality but higher forming efficiency; when the number of forming contours is 2 to 3, the part surface quality meets the requirements and the forming efficiency is also relatively high. Therefore, the number of contours is controlled to be 2 to 3.

[0062] Specifically, in step 4 above, considering that when the electron beam forming contour region is in operation, if the spacing between adjacent scan contours is too large, incomplete fusion will occur between the contours, and if the spacing is too small, overburning will occur between the contours, the scanning line spacing L2 of the electron beam forming contour region is 0.1mm to 0.15mm.

[0063] Specifically, in step 5 above, the hot isostatic pressing (HIP) process includes: a HIP temperature of 900℃~1200℃, a HIP pressure of 120MPa~160MPa, and a holding time of 3h~5h. Under these HIP conditions, the diffusion of segregated elements can be promoted, the microstructure optimized, and the part microstructure homogenized; simultaneously, the alloy is fully densified during the HIP process.

[0064] It should be noted that the above-mentioned nickel-based superalloys can be GH4169, K438, CM247LC, GH3536, GH3625, GH4099, GH3030, etc.

[0065] Compared with the prior art, the present invention uses segmented discontinuous scanning instead of continuous scanning and precisely controls process parameters in the core area of ​​electron beam forming of parts, thereby reducing the internal stress generated during the printing process; furthermore, by precisely controlling the process parameters in the core area and contour area of ​​electron beam forming of parts, the risk of crack defects in high-temperature alloy samples is reduced.

[0066] The advantages of the method of the present invention will be demonstrated below with specific embodiments and comparative examples.

[0067] Example 1

[0068] This embodiment uses electron beam forming of a K438 tapered part. A schematic diagram of the three-dimensional model of the K438 tapered part is shown below. Figure 1 As shown. The method for electron beam additive manufacturing of the K438 tapered part includes the following steps:

[0069] Step 1: Design a 3D model of part K438 using software. The dimensions of the K438 tapered part are 45mm × 45mm × 45mm.

[0070] Step 2: Import the 3D model of the part into the Magics software platform to repair the model. Place the repaired model on the printing platform. After completing the repair and placement of the model, export the model as an STL file and import the STL file into the printing device.

[0071] Step 3: Preheat the substrate at 1000℃;

[0072] Step 4: The electron beam shapes the core area and contour area of ​​the part respectively, and prints the initial part;

[0073] The 3*3mm blocks were selected. When forming the core area, the accelerating voltage U1 was 60000V, the layer thickness H1 was 0.8mm, the scanning beam current I1 was 20mA, the scanning rate V1 was 15mm / s, and the scanning line spacing L1 was 0.5mm.

[0074] When forming the contour area, there are 2 contours, the accelerating voltage U2 is 60000V, the layer thickness H2 is 0.8mm, the scanning beam current I2 is 15mA, the scanning rate V2 is 60mm / s, and the distance L2 between the outer contour and the inner contour is 0.1mm.

[0075] Step 5: Perform hot isostatic pressing on the initial part to obtain the final part.

[0076] The hot isostatic pressing temperature was 1180℃, the hot isostatic pressing pressure was 160MPa, and the time was 3h.

[0077] The surface roughness of the final K438 tapered part in this embodiment is Ra5.6μm, the density of the tapered part is 99.8%, and its mechanical properties at room temperature are tensile strength Rm>850MPa and elongation A>35%, and its mechanical properties at 1100℃ are tensile strength Rm>180MPa and elongation A>15%; there are no cracks.

[0078] Example 2

[0079] This embodiment uses electron beam forming of a CM247LC cuboid part. A schematic diagram of the 3D model of the CM247LC cuboid part is shown below. Figure 2 As shown. The method for electron beam additive manufacturing of the CM247LC cuboid part includes the following steps:

[0080] Step 1: Design a 3D model of the CM247LC cuboid component using software. The dimensions of the CM247LC cuboid component are 60mm × 60mm × 90mm.

[0081] Step 2: Import the 3D model of the part into the Magics software platform to repair the model. Place the repaired model on the printing platform. After completing the repair and placement of the model, export the model as an STL file and import the STL file into the printing device.

[0082] Step 3: Preheat the substrate at 1200℃;

[0083] Step 4: The electron beam shapes the core area and contour area of ​​the part respectively, and prints the initial part;

[0084] The 5*5mm blocks were selected. When forming the core area, the accelerating voltage U1 was 60000V, the layer thickness H1 was 0.7mm, the scanning beam current I1 was 25mA, the scanning rate V1 was 13mm / s, and the scanning line spacing L1 was 0.65mm.

[0085] When forming the contour area, there are 2 contours, the accelerating voltage U2 is 60000V, the layer thickness H2 is 0.7mm, the scanning beam current I2 is 14mA, the scanning rate V2 is 56mm / s, and the distance L2 between the outer contour and the inner contour is 0.12mm.

[0086] Step 5: Perform hot isostatic pressing on the initial part to obtain the final part.

[0087] The hot isostatic pressing temperature was 1180℃, the hot isostatic pressing pressure was 150MPa, and the time was 4h.

[0088] The final CM247LC cuboid part formed in this embodiment has a surface roughness of Ra6.0μm and a density of 99.76% for the tapered part. Its room temperature mechanical properties are tensile strength Rm>850MPa and elongation A>35%, and its 1100℃ mechanical properties are tensile strength Rm>180MPa and elongation A>15%; it is free of cracks.

[0089] Example 3

[0090] This embodiment uses electron beam forming of the GH3536 structural component. The method for electron beam additive manufacturing of the GH3536 structural component includes the following steps:

[0091] Step 1: Design a 3D model of the GH3536 structural component using software. The dimensions of the GH3536 structural component are 100mm × 50mm × 100mm.

[0092] Step 2: Import the 3D model of the part into the Magics software platform to repair the model. Place the repaired model on the printing platform. After completing the repair and placement of the model, export the model as an STL file and import the STL file into the printing device.

[0093] Step 3: Preheat the substrate at 850℃;

[0094] Step 4: The electron beam shapes the core area and contour area of ​​the part respectively, and prints the initial part;

[0095] The 7*7mm blocks were selected. When forming the core area, the accelerating voltage U1 was 60000V, the layer thickness H1 was 0.85mm, the scanning beam current I1 was 27mA, the scanning rate V1 was 23mm / s, and the scanning line spacing L1 was 0.75mm.

[0096] When forming the contour area, there are 2 contours, the accelerating voltage U2 is 60000V, the layer thickness H2 is 0.85mm, the scanning beam current I2 is 14mA, the scanning rate V2 is 60mm / s, and the distance L2 between the outer contour and the inner contour is 0.11mm.

[0097] Step 5: Perform hot isostatic pressing on the initial part to obtain the final part.

[0098] The hot isostatic pressing temperature was 1170℃, the hot isostatic pressing pressure was 140MPa, and the time was 3h.

[0099] The final GH3536 structural component formed in this embodiment has a surface roughness of Ra5.8μm, a tapered component density of 99.88%, and room temperature mechanical properties of tensile strength Rm>700MPa and elongation A>40%, and mechanical properties at 815℃ of tensile strength Rm>300MPa and elongation A>20%; it is free of cracks.

[0100] Comparative Example 1

[0101] This comparative example provides a method for electron beam additive manufacturing of nickel-based superalloys. This comparative example forms the K438 tapered part of Example 1. The method of this comparative example is largely the same as that of Example 1, with the following differences:

[0102] The 3*3mm blocks were selected. When forming the core area, the accelerating voltage U1 was 60000V, the layer thickness H1 was 0.8mm, the scanning beam current I1 was 9mA, the scanning rate V1 was 30mm / s, and the scanning line spacing L1 was 0.04mm.

[0103] When forming the contour area, there is one contour, the accelerating voltage U2 is 60000V, the layer thickness H2 is 0.8mm, the scanning beam current I2 is 16mA, the scanning rate V2 is 75mm / s, and the distance L2 between the outer contour and the inner contour is 0.1mm.

[0104] The tapered part that can be formed in this proportion cannot be formed.

[0105] Comparative Example 2

[0106] This comparative example provides a method for electron beam additive manufacturing of nickel-based superalloys. The comparative example forms the CM247LC cuboid part of Example 2. The method of this comparative example is largely the same as that of Example 2, with the following differences:

[0107] The 5*5mm blocks were selected. When forming the core area, the accelerating voltage U1 was 60000V, the layer thickness H1 was 1.0mm, the scanning beam current I1 was 9mA, the scanning rate V1 was 20mm / s, and the scanning line spacing L1 was 1.1mm.

[0108] When forming the contour area, there are 2 contours, the accelerating voltage U2 is 60000V, the layer thickness H2 is 1.0mm, the scanning beam current I2 is 4mA, the scanning rate V2 is 75mm / s, and the distance L2 between the outer contour and the inner contour is 0.12mm.

[0109] The surface roughness of the GH3536 structural component finally formed in this comparative example is Ra 15.4 micrometers, the density of the tapered part is 95.8%, and its room temperature mechanical properties are tensile strength Rm of 715MPa-796MPa and elongation A of 10%-12%. Its mechanical properties at 1100℃ are tensile strength Rm of 90MPa-120MPa and elongation A of 5-8%. Cracks are present.

[0110] Comparative Example 3

[0111] This comparative example provides a method for electron beam additive manufacturing of nickel-based superalloys. This comparative example forms a GH3536 structural part. The method of this comparative example is largely the same as that of Example 3, with the following differences:

[0112] The 7*7mm blocks were selected. When forming the core area, the accelerating voltage U1 was 60000V, the layer thickness H1 was 1.1mm, the scanning beam current I1 was 8mA, the scanning rate V1 was 32mm / s, and the scanning line spacing L1 was 0.75mm.

[0113] When forming the contour area, there are 2 contours, the accelerating voltage U2 is 60000V, the layer thickness H2 is 1.1mm, the scanning beam current I2 is 5mA, the scanning rate V2 is 75mm / s, and the distance L2 between the outer contour and the inner contour is 0.9mm.

[0114] The surface roughness of the GH3536 structural component finally formed in this comparative example is Ra20.5μm, the density of the tapered part is 95.5%, and its room temperature mechanical properties are tensile strength Rm of 490MPa-562MPa and elongation A of 13%-22%. Its mechanical properties at 815℃ are tensile strength Rm of 194MPa-216MPa and elongation A of 9-14%. Cracks are present.

[0115] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for electron beam additive manufacturing of nickel-based superalloys, characterized in that, Includes the following steps: Step 1: Design a 3D model of the part using software; Step 2: Import the 3D model of the part into the Magics software platform to repair the model. Place the repaired model on the printing platform. After completing the repair and placement of the model, export the model as an STL file and import the STL file into the printing device. Step 3: Preheat the substrate; Step 4: The electron beam shapes the core area and contour area of ​​the part respectively, and prints the initial part; Step 5: Perform hot isostatic pressing on the initial part to obtain the final part; In step 4, the scanning beam current I2 of the electron beam forming part contour region is less than the scanning beam current I1 of the electron beam forming part core region, and the scanning rate V2 of the electron beam forming part contour region is greater than the scanning rate V1 of the electron beam forming part core region. In step 4, the printing process employs block-based non-continuous scanning; In step 4, the scanning beam current I1 of the core region of the electron beam forming part is 10mA~30mA, the accelerating voltage U1 of the core region of the electron beam forming part is 60000V, the scanning rate V1 of the core region of the electron beam forming part is 10mm / s~27mm / s, the layer thickness H1 of the core region of the electron beam forming part is 0.05mm-1mm, and the scanning line spacing L1 of the core region of the electron beam forming part is 0.5mm~1mm. The scanning beam current I2 of the electron beam forming part contour region is 5mA~15mA, the accelerating voltage U2 of the electron beam forming part contour region is 60000V, the scanning rate V2 of the electron beam forming part contour region is 50mm / s~70mm / s, the layer thickness H2 of the electron beam forming part contour region is 0.05mm-1mm, and the spacing L2 between adjacent scanning contours during electron beam forming of the contour region is 0.1mm~0.15mm.

2. The method according to claim 1, characterized in that, In step 3, the temperature of the preheated substrate is 850℃~1200℃.

3. The method according to claim 1, characterized in that, In step 4, the block size is 0.

5. 3mm, 1 3mm, 3 3mm, 5 5mm, 7 One of the 7mm sizes.

4. The method according to claim 3, characterized in that, In step 4, the number of contour regions is 2 to 3.

5. The method according to claim 4, characterized in that, In step 4, the energy thermal input E of the core region of the electron beam forming part satisfies: E=(I1×U1) / (V1×H1×L1); Where E is the energy thermal input of the core region of the electron beam formed part, in J / mm². 3 , I1 represents the scanning beam current in the core region of the electron beam shaped part, in mA. U1 is the accelerating voltage (V) in the core region of the electron beam forming part. V1 is the scanning rate of the core region of the electron beam-formed part, in mm / s. H1 represents the layer thickness of the core region of the electron beam formed part, in mm. L1 is the scanning line spacing of the core area of ​​the electron beam forming part, in mm.

6. The method according to claim 1, characterized in that, In step 5, the hot isostatic pressing temperature is 900℃~1200℃, and the hot isostatic pressing pressure is 120MPa~160MPa.

7. The method according to claim 6, characterized in that, In step 5, the hot isostatic pressing and heat preservation time is 3h~5h.

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