A processing method for RAFM steel
By using selective laser melting additive manufacturing and vacuum electron beam welding technology, the problems of cumbersome processing and long cycle of RAFM steel plates have been solved, the performance of welded joints has been improved, and the rapid preparation requirements of fusion reactor blankets have been met.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HEFEI INSTITUTE OF PHYSICAL SCIENCE CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2023-04-24
- Publication Date
- 2026-05-26
AI Technical Summary
The existing forging process for RAFM steel plates is cumbersome and time-consuming, and the performance of the welded joints is poor, making it difficult to meet the processing requirements of fusion reactor blankets.
RAFM steel plates were prepared using selective laser melting additive manufacturing process, and fusion reactor blankets were deposited layer by layer through tempering heat treatment and vacuum electron beam welding. The microstructure was refined by utilizing the rapid melting and cooling characteristics of laser, thereby improving the performance of welded joints.
It enables rapid and low-cost processing of fusion reactor blankets, with excellent welded joint performance, solving the problems of cumbersome processing and long cycle time, while improving the comprehensive mechanical properties of RAFM steel plates.
Smart Images
Figure CN116460307B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of manufacturing processes for ferritic / martensitic steels, and more particularly to a method for processing RAFM steel. Background Technology
[0002] Low-activation ferritic / martensitic steel (RAFM steel) has high thermal conductivity, low coefficient of thermal expansion, excellent resistance to neutron irradiation and comprehensive mechanical properties, and has become the preferred structural material for the blanket of thermonuclear experimental reactors and future thermonuclear demonstration fusion reactors.
[0003] RAFM steel is the preferred structural material for fusion reactor blankets. Currently, RAFM steel plates are forged and then assembled using welding technology to obtain the fusion reactor blanket. However, this forging method has the problems of complicated processing and long processing cycle, and the performance of the welded joints between RAFM steel plates in the fusion reactor blanket is poor. Summary of the Invention
[0004] This application provides a method for processing RAFM steel, which can solve the problems of cumbersome processing and long processing cycle of fusion reactor blanket, and at the same time improve the performance of welded joints between RAFM steel plates in fusion reactor blanket.
[0005] To achieve the above objectives, this application adopts the following technical solution:
[0006] This application provides a method for processing RAFM steel, the method comprising:
[0007] Obtain the target RAFM steel powder;
[0008] Selective laser melting additive manufacturing process was used to prepare target RAFM steel powder into RAFM steel plate;
[0009] The RAFM steel plate is subjected to quenching and tempering heat treatment to obtain the target RAFM steel plate;
[0010] Multiple target RAFM steel plates are vacuum electron beam welded to obtain welded joints between the target RAFM steel plates, and then assembled to obtain the fusion reactor blanket structure.
[0011] In one embodiment, obtaining the target RAFM steel powder includes:
[0012] Obtaining raw materials;
[0013] The raw materials are vacuum melted to obtain the target steel ingot;
[0014] The target steel ingot is subjected to gas atomization treatment to obtain RAFM steel powder;
[0015] The RAFM steel powder is dried to obtain the target RAFM steel powder.
[0016] In one embodiment, the target steel ingot is subjected to gas atomization treatment to obtain RAFM steel powder, comprising:
[0017] The target steel ingot is melted in a vacuum induction furnace and then atomized using an inert gas to obtain RAFM steel powder.
[0018] In one embodiment, the raw materials include:
[0019] C: 0.08%-0.135%, Cr: 8.2%-8.8%, Mn: 0.3%-0.7%, W: 1.3%-1.7%, V: 0.2%-0.4%, Ta: 0.05%-0.15%, N: 0.015%-0.04%, O: ≤0.032%, with the remainder being Fe and impurity elements.
[0020] In one embodiment, the particle size range of the raw material is 15-53 μm, the Hall flow rate of the raw material is 15-30 s / 50 g, and the loose packing density of the raw material is 4-4.5 g / cm³. 3 The tap density of the raw material is 4.5-5 g / cm³. 3 .
[0021] In one embodiment, the process parameters for the drying process include:
[0022] The drying temperature is 100-150℃, and the holding time is 4-8 hours.
[0023] In one embodiment, a selective laser melting additive manufacturing process is used to prepare a target RAFM steel powder into a RAFM steel plate, comprising:
[0024] The target RAFM steel powder is placed in the forming chamber of a selective laser melting device for melting and forming to obtain RAFM steel plate. The oxygen content in the forming chamber of the selective laser melting device is less than 0.1%.
[0025] In one embodiment, the process parameters for melt forming include:
[0026] Laser power: 220-260W, laser scanning speed: 600-1000mm / s, scanning spacing: 80-100μm, layer thickness: 30-45μm, preheating temperature: 100-120℃, scanning path: bidirectional zigzag scanning, rotating 90° per layer.
[0027] In one embodiment, RAFM steel sheet is subjected to quenching and tempering heat treatment to obtain the target RAFM steel sheet, including:
[0028] The RAFM steel plate is quenched, held at 960-980℃ for 30-45 minutes, and then water-cooled to room temperature to obtain the intermediate RAFM steel plate.
[0029] The intermediate RAFM steel plate is tempered by heating to 740-760℃ and holding for 90-100 minutes, then air-cooled to room temperature to obtain the target RAFM steel plate.
[0030] In one embodiment, the welding process parameters for vacuum electron beam welding include:
[0031] The welding voltage is 150kV, the welding beam current is 25-35mA, the welding focusing current is 2200-2300mA, the welding speed is 10-15mm / s, the welding working distance is 400mm, and there is no scanning deflection during the welding process.
[0032] The beneficial effects of the technical solutions provided in this application include at least the following:
[0033] The RAFM steel processing method provided in this application uses selective laser melting additive manufacturing process to prepare RAFM steel plates, which can then be welded and assembled to obtain the fusion reactor blanket. Since selective laser melting additive manufacturing technology can deposit layers one by one according to the scanning path controlled by software, it can manufacture the blanket RAFM steel components in one piece without the need for molds and with low cost and short cycle. Therefore, it can solve the problem of cumbersome processing and long processing cycle of fusion reactor blanket.
[0034] Meanwhile, the rapid melting and cooling characteristics of lasers in selective laser melting additive manufacturing technology can refine the martensite and ferrite structure in RAFM steel plates, thereby improving the comprehensive mechanical properties of RAFM steel plates and thus improving the performance of welded joints between RAFM steel plates.
[0035] Furthermore, by subjecting RAFM steel plates to quenching and tempering heat treatment, the microstructure of RAFM steel plates can be further homogenized, which can solve the problem of compositional segregation during the casting of large metal components. Then, by performing vacuum electron beam welding on the target RAFM steel, welded joints with good surface forming and excellent performance, as well as fusion reactor blankets, can be obtained. Attached Figure Description
[0036] Figure 1 A flowchart illustrating a processing method for RAFM steel provided in this application embodiment;
[0037] Figure 2 A microstructure diagram of a RAFM steel plate provided in an embodiment of this application;
[0038] Figure 3 A microstructure diagram of a target RAFM steel plate provided for an embodiment of this application;
[0039] Figure 4 A microstructure of the weld in a RAFM steel welded joint provided in this application embodiment;
[0040] Figure 5 Microstructure of a weld in a forged RAFM steel welded joint provided as a comparative example of this application;
[0041] Figure 6 Stress-strain curves of the RAFM steel plates provided in Examples 1 and 2 of this application;
[0042] Figure 7 Stress-strain curves of RAFM steel welded joints provided in Embodiment 3 and Comparative Example 1 of this application. Detailed Implementation
[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0044] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more.
[0045] In addition, the use of “based on” or “according to” implies openness and inclusivity, because processes, steps, calculations or other actions “based on” or “according to” one or more conditions or values can in practice be based on additional conditions or values beyond those conditions.
[0046] Figure 1 A processing method for RAFM steel provided in this application embodiment, such as Figure 1 As shown, the method includes the following steps:
[0047] Step 101: Obtain the target RAFM steel powder.
[0048] The process of obtaining the target RAFM steel powder, or the process of preparing the target RAFM steel powder, can be as follows:
[0049] Obtain raw materials, vacuum melt the raw materials to obtain target steel ingots, perform gas atomization treatment on the target steel ingots to obtain RAFM steel powder, and perform drying treatment on the RAFM steel powder to obtain target RAFM steel powder.
[0050] Optionally, the process of atomizing the target steel ingot to obtain RAFM steel powder can be as follows:
[0051] The target steel ingot is melted in a vacuum induction furnace and then atomized using an inert gas to obtain RAFM steel powder.
[0052] The raw materials include: C: 0.08%-0.135%, Cr: 8.2%-8.8%, Mn: 0.3%-0.7%, W: 1.3%-1.7%, V: 0.2%-0.4%, Ta: 0.05%-0.15%, N: 0.015%-0.04%, O: ≤0.032%, with the remainder being Fe and impurities. The particle size range of the raw materials is 15-53 μm, the Hall flow rate is 15-30 s / 50 g, and the bulk density is 4-4.5 g / cm³. 3 The tap density of the raw material is 4.5-5 g / cm³. 3 .
[0053] When drying RAFM steel powder as described above, the drying process parameters include: drying temperature: 100-150℃, and holding time: 4-8h.
[0054] In actual practice, the RAFM steel powder prepared by gas atomization can be placed in a vacuum drying oven and heated to 100°C for 4 hours.
[0055] Step 102: Use selective laser melting additive manufacturing process to prepare RAFM steel powder into RAFM steel plate.
[0056] Selective laser melting (SLM) is a major technique in additive manufacturing of metal materials. This technique uses a laser as an energy source and scans the metal powder bed layer by layer according to a pre-planned path in a 3D CAD slicing model. The scanned metal powder melts and solidifies to achieve a metallurgical bond, ultimately obtaining the metal part designed in the model.
[0057] Optionally, the target RAFM steel powder is placed in the forming chamber of a selective laser melting device for melting and forming, wherein the oxygen content in the forming chamber of the selective laser melting device is less than 0.1%.
[0058] In the actual implementation process, the forming chamber of the laser melting equipment in the selected area needs to be cleaned in the early stage to ensure that the surface of the substrate in the forming chamber is clean and flat, the surface of the galvanometer is free of dust adsorption, and the scraper is intact and undamaged. Then, the oxygen in the forming chamber is discharged by filling it with argon gas to avoid the formation of oxides.
[0059] The process parameters for placing the target RAFM steel powder into the forming chamber of the selective laser melting equipment for melting and forming include:
[0060] Laser power: 220-260W, laser scanning speed: 600-1000mm / s, scanning spacing: 80-100μm, layer thickness: 30-45μm, preheating temperature: 100-120℃, scanning path: bidirectional zigzag scanning, rotating 90° per layer.
[0061] Step 103: Perform quenching and tempering heat treatment on the RAFM steel plate to obtain the target RAFM steel plate.
[0062] Optionally, the RAFM steel plate can be quenched, held at 960-980℃ for 30-45 minutes and then water-cooled to room temperature to obtain an intermediate RAFM steel plate; the intermediate RAFM steel plate can be tempered, heated to 740-760℃, held for 90-100 minutes and then air-cooled to room temperature to obtain the target RAFM steel plate.
[0063] Step 104: Vacuum electron beam welding is performed on multiple target RAFM steel plates to obtain welded joints between the target RAFM steel plates, and the fusion reactor blanket structure is obtained by assembly.
[0064] In actual execution, the target RAFM steel can be cut and sampled to obtain two RAFM steel plates of 150×52×5mm. A 150×10×10mm backing plate is added to ensure full penetration. Vacuum electron beam butt welding is then performed on the RAFM steel plates to obtain a high-performance welded joint. The welding process parameters for vacuum electron beam welding include: welding voltage: 150kV, welding beam current: 30mA, welding focusing current: 2250mA, welding speed: 13mm / s, welding working distance: 400mm, and no scanning deflection during the welding process.
[0065] The RAFM steel processing method provided in this application uses selective laser melting additive manufacturing process to prepare RAFM steel plates, which can then be welded and assembled to obtain the fusion reactor blanket. Since selective laser melting additive manufacturing technology can deposit layers one by one according to the scanning path controlled by software, it can manufacture the blanket RAFM steel components in one piece without the need for molds and with low cost and short cycle. Therefore, it can solve the problem of cumbersome processing and long processing cycle of fusion reactor blanket.
[0066] Meanwhile, the rapid melting and cooling characteristics of lasers in selective laser melting additive manufacturing technology can refine the martensite and ferrite structure in RAFM steel plates, thereby improving the comprehensive mechanical properties of RAFM steel plates and thus improving the performance of welded joints between RAFM steel plates.
[0067] Furthermore, by subjecting RAFM steel plates to quenching and tempering heat treatment, the microstructure of RAFM steel plates can be further homogenized, which can solve the problem of compositional segregation during the casting of large metal components. Then, by performing vacuum electron beam welding on the target RAFM steel, welded joints with good surface forming and excellent performance, as well as fusion reactor blankets, can be obtained.
[0068] In addition, this application provides some specific embodiments.
[0069] Example 1: A process for preparing RAFM steel plate is provided, the specific process is as follows:
[0070] The raw materials were obtained with the following alloying elements and their corresponding percentage contents: C: 0.095%, Cr: 8.57%, Mn: 0.54%, W: 1.6%, V: 0.3%, Ta: 0.15%, N: 0.02%, O: 0.025%, with the remainder being Fe and impurity elements. The raw material particle size ranged from 15 to 53 μm, the Hall flow rate was 20.1 s / 50 g, and the loose packing density was 4.23 g / cm³. 3 Tap density 4.8 g / cm³ 3 .
[0071] The raw materials are vacuum melted to obtain the target steel ingot;
[0072] The target steel ingot is melted in a vacuum induction furnace and then atomized using an inert gas to obtain RAFM steel powder.
[0073] The RAFM steel powder was dried to obtain the target RAFM steel powder. The drying temperature was 100℃ and the holding time was 4h.
[0074] The target RAFM steel powder is placed in the forming chamber of a selective laser melting (SLM) device for melting and forming to obtain RAFM steel plates. The oxygen content in the forming chamber is less than 0.1%. The melting and forming process parameters include: laser power of 240W, laser scanning speed of 600mm / s, scanning interval of 90μm, layer thickness of 40μm, preheating temperature of 120℃, and scanning path of bidirectional zigzag scanning with 90° rotation per layer. Figure 2 The image shown is a microstructure diagram of the RAFM steel plate prepared in the above embodiment.
[0075] Example 2: A process for preparing a target RAFM steel plate is provided, the specific process is as follows:
[0076] The raw materials were obtained with the following alloying elements and their corresponding percentage contents: C: 0.095%, Cr: 8.57%, Mn: 0.54%, W: 1.6%, V: 0.3%, Ta: 0.15%, N: 0.02%, O: 0.025%, with the remainder being Fe and impurity elements. The raw material particle size ranged from 15 to 53 μm, the Hall flow rate was 20.1 s / 50 g, and the loose packing density was 4.23 g / cm³. 3 Tap density 4.8 g / cm³ 3 .
[0077] The raw materials are vacuum melted to obtain the target steel ingot;
[0078] The target steel ingot is melted in a vacuum induction furnace and then atomized using an inert gas to obtain RAFM steel powder.
[0079] The RAFM steel powder was dried to obtain the target RAFM steel powder. The drying temperature was 100℃ and the holding time was 4h.
[0080] The target RAFM steel powder is placed in the forming chamber of a selective laser melting equipment for melting and forming to obtain RAFM steel plate. The oxygen content in the forming chamber of the selective laser melting equipment is less than 0.1%. The process parameters for melting and forming include: laser power: 240W, laser scanning speed: 600mm / s, scanning interval: 90μm, layer thickness: 40μm, preheating temperature: 120℃, scanning path: bidirectional zigzag scanning, with each layer rotating 90°.
[0081] The RAFM steel plate was quenched, held at 980℃ for 45 minutes, and then water-cooled to room temperature to obtain the intermediate RAFM steel plate.
[0082] The intermediate RAFM steel plate was tempered by heating to 740℃, holding for 90 minutes, and then air-cooled to room temperature to obtain the target RAFM steel plate. The microstructure of the target RAFM steel plate is shown in the figure below. Figure 3 As shown. (Through) Figure 2 and Figure 3 The comparison shows that the RAFM steel plate after tempering has a more uniform structure and a higher recrystallization fraction after homogenization heat treatment, which leads to improved plasticity. The structure also changes from coarse martensite to finer sorbite after tempering.
[0083] Example 3: A process for preparing a welded joint between target RAFM steel plates is provided, the specific process is as follows.
[0084] The raw materials were obtained with the following alloying elements and their corresponding percentage contents: C: 0.095%, Cr: 8.57%, Mn: 0.54%, W: 1.6%, V: 0.3%, Ta: 0.15%, N: 0.02%, O: 0.025%, with the remainder being Fe and impurity elements. The raw material particle size ranged from 15 to 53 μm, the Hall flow rate was 20.1 s / 50 g, and the loose packing density was 4.23 g / cm³. 3 Tap density 4.8 g / cm³ 3 .
[0085] The raw materials are vacuum melted to obtain the target steel ingot;
[0086] The target steel ingot is melted in a vacuum induction furnace and then atomized using an inert gas to obtain RAFM steel powder.
[0087] The RAFM steel powder was dried to obtain the target RAFM steel powder. The drying temperature was 100℃ and the holding time was 4h.
[0088] The target RAFM steel powder is placed in the forming chamber of a selective laser melting equipment for melting and forming to obtain RAFM steel plate. The oxygen content in the forming chamber of the selective laser melting equipment is less than 0.1%. The process parameters for melting and forming include: laser power: 240W, laser scanning speed: 600mm / s, scanning interval: 90μm, layer thickness: 40μm, preheating temperature: 120℃, scanning path: bidirectional zigzag scanning, with each layer rotating 90°.
[0089] The RAFM steel plate was quenched, held at 980℃ for 45 minutes, and then water-cooled to room temperature to obtain the intermediate RAFM steel plate.
[0090] The intermediate RAFM steel plate was tempered by heating to 740℃ and holding for 90 minutes, then air-cooled to room temperature to obtain the target RAFM steel plate.
[0091] Multiple target RAFM steel plates were vacuum electron beam welded to obtain welded joints between the target RAFM steel plates. The welding process parameters for vacuum electron beam welding included: welding voltage of 150kV, welding beam current of 30mA, welding focusing current of 2250mA, welding speed of 13mm / s, welding working distance of 400mm, and no scanning deflection during the welding process.
[0092] Specifically, the target RAFM steel can be cut and sampled to obtain two RAFM steel plates of 150×52×5mm. A 150×10×10mm backing plate is added to ensure full penetration. Vacuum electron beam butt welding is then performed on the RAFM steel plates to obtain a welded joint between the target RAFM steel plates. The microstructure of the weld is shown in the figure below. Figure 4 As shown. From Figure 4 It can be seen that the large martensitic structure in the center of the weld is due to the large heat input during welding, the fast cooling rate, and the large temperature gradient in the center of the weld. The grains grow in a columnar shape along the temperature gradient direction.
[0093] This application also provides a comparative example, which is a welded joint between RAFM steel plates prepared using existing technology. The specific process is as follows:
[0094] The raw materials are vacuum melted to obtain the target steel ingot;
[0095] The alloying elements and their corresponding percentage contents of the target steel are as follows: C: 0.093%, Cr: 8.96%, Mn: 0.48%, W: 1.47%, V: 0.16%, Ta: 0.11%, Si: 0.042%, with the remainder being Fe and impurity elements.
[0096] Remove the surface oxide scale from the target steel ingot and forge two 150×52×5mm RAFM steel butt test plates and one 150×10×10mm RAFM steel pad plate.
[0097] Two processed RAFM steel test plates were subjected to electron beam welding to obtain a welded joint between the RAFM steels. The electron beam welding process parameters were: voltage 150kV, beam current 30mA, focusing current 2250mA, welding speed 13mm / s, working distance 400mm, and no scanning deflection. The microstructure of the welded joint between the RAFM steels in the comparative example of this application is shown in the figure below. Figure 5 As shown. (Through) Figure 4 and Figure 5 The comparison shows that the grain size of the RAFM steel weld in Example 3 is smaller than that of the RAFM steel weld in the comparative example. According to the principle of fine grain strengthening, the weld strength of the welded joint obtained by the RAFM steel processing method provided in this application is better than that of the welded joint obtained by forging in the prior art.
[0098] Table 1 shows the performance results of the RAFM steel and its welded joints in the above embodiments.
[0099]
[0100] As shown in Table 1, the plasticity and impact toughness of RAFM steel are significantly improved after quenching and tempering heat treatment. The mechanical properties of the welded joints exhibit both good plasticity and excellent strength. For specific mechanical property characterization, please refer to [reference needed]. Figure 6Furthermore, the welded joints between target RAFM steel plates prepared by the processing method of the RAFM steel provided in this application exhibit superior tensile strength and yield strength compared to welded joints of forged RAFM steel in the prior art, while also demonstrating better plasticity. Specific mechanical property characterization can be found in [reference needed]. Figure 7 .
[0101] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.
[0102] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A method for processing RAFM steel, characterized in that, The method includes: The target RAFM steel powder is obtained from raw materials comprising: C: 0.08%-0.135%, Cr: 8.2%-8.8%, Mn: 0.3%-0.7%, W: 1.3%-1.7%, V: 0.2%-0.4%, Ta: 0.05%-0.15%, N: 0.015%-0.04%, O: ≤0.032%, with the remainder being Fe and impurities. The particle size range of the raw materials is 15-53 μm, the Hall flow rate is 15-30 s / 50g, and the bulk density is 4-4.5 g / cm³. 3 The tap density of the raw material is 4.5-5 g / cm³. 3 ; The target RAFM steel powder is placed in the forming chamber of a selective laser melting device for melting and forming to obtain a RAFM steel plate. The oxygen content in the forming chamber of the selective laser melting device is less than 0.1%. The process parameters for melting and forming include: laser power: 220-260W, laser scanning speed: 600-1000 mm / s, scanning spacing: 80-100 μm, layer thickness: 30-45 μm, preheating temperature: 100-120℃, and scanning path: bidirectional zigzag scanning with 90° rotation per layer. The RAFM steel plate is subjected to quenching and tempering heat treatment to obtain the target RAFM steel plate; Multiple target RAFM steel plates are vacuum electron beam welded to obtain welded joints between the target RAFM steel plates, and then assembled to obtain the fusion reactor blanket structure.
2. The method according to claim 1, characterized in that, The acquisition of the target RAFM steel powder includes: Obtaining raw materials; The raw materials are vacuum melted to obtain the target steel ingot; The target steel ingot is subjected to gas atomization treatment to obtain RAFM steel powder; The RAFM steel powder is dried to obtain the target RAFM steel powder.
3. The method according to claim 2, characterized in that, The step of subjecting the target steel ingot to gas atomization treatment to obtain RAFM steel powder includes: The target steel ingot is melted in a vacuum induction furnace and then atomized using an inert gas to obtain the RAFM steel powder.
4. The method according to claim 2, characterized in that, The process parameters for the drying process include: The drying temperature is 100-150℃, and the holding time is 4-8 hours.
5. The method according to claim 1, characterized in that, The step of subjecting the RAFM steel plate to quenching and tempering heat treatment to obtain the target RAFM steel plate includes: The RAFM steel plate is quenched, held at 960-980℃ for 30-45 min and then water-cooled to room temperature to obtain the intermediate RAFM steel plate. The intermediate RAFM steel plate is tempered by heating to 740-760℃ and holding for 90-100 minutes, then air-cooled to room temperature to obtain the target RAFM steel plate.
6. The method according to claim 1, characterized in that, The welding process parameters for the vacuum electron beam welding include: The welding voltage is 150 kV, the welding beam current is 25-35 mA, the welding focusing current is 2200-2300 mA, the welding speed is 10-15 mm / s, the welding working distance is 400 mm, and there is no scanning deflection during the welding process.