Welding Structure and Welding Method of CuCrZr Tube and 316L Tube in Fusion Device

Abstract

This invention belongs to the technical field of divertor cooling tubes for fusion devices, and discloses a welding structure and method for CuCrZr and 316L tubes in a fusion device. The welding structure includes a nickel-chromium-molybdenum alloy tube, a CuCrZr tube, and a 316L tube; one end of the nickel-chromium-molybdenum alloy tube and one end of the CuCrZr tube, as well as the other end of the nickel-chromium-molybdenum alloy tube and one end of the 316L tube, are coaxially connected by vacuum electron beam welding. This invention can ensure joint strength, weld formation quality, control the internal weld reinforcement without affecting the internal cooling channels, and has high welding efficiency.

Description

Technical Field

[0001] This invention relates to the field of divertor cooling tube technology for fusion devices, and more particularly to a welding structure and welding method for CuCrZr tubes and 316L tubes in fusion devices. Background Technology

[0002] Controlled thermonuclear fusion is an ideal new energy source to meet humanity's future energy needs, but the high-temperature plasma components of the divertor require highly efficient cooling. This necessitates the design of a heat transfer element capable of operating under the high-temperature and high-pressure conditions of these components. Copper-chromium-zirconium alloy (CuCrZr alloy), as an important high-performance material, possesses excellent electrical and thermal conductivity, high hardness, wear resistance, and explosion resistance. The high-precision CuCrZr tube structure (including straight tubes and coiled tubes) removes heat through the medium flowing within the CuCrZr tube, ensuring the normal operation of the fusion device. Furthermore, the high-temperature plasma components often require a 316L material structure as a support component fixed inside the vacuum chamber. Therefore, the CuCrZr tube needs to be connected to the 316L tube in the support structure's flow channel, and the cooling system must remain unaffected even after decades of stable operation of the fusion device. This places extremely high demands on the manufacturing process of the entire piping system, including the welding structure between the CuCrZr and 316L tubes.

[0003] CuCrZr alloy is a high-strength, high-conductivity copper alloy with excellent thermal and electrical conductivity and high-temperature mechanical properties. 316L, on the other hand, is an ultra-low-carbon austenitic stainless steel with strong corrosion resistance, but its physical and metallurgical properties differ significantly from CuCrZr. Welding these two dissimilar metals is a difficult combination, with the core challenge lying in their poor metallurgical compatibility and mismatched physical properties. Traditional fusion welding methods are rarely effective in joining these two materials. Existing technologies mainly employ brazing or hot isostatic pressing (HIP) welding for connection, but these methods have the following drawbacks: For brazing, the joint strength is low and prone to defects. Existing defects make it difficult to guarantee safe use over a long period of time. As for hot isostatic pressure welding, it is a welding method that involves pressurizing and heating in a vacuum environment. However, this manufacturing method requires pressurization and is generally suitable for plate-shaped materials. It is not suitable for welding CuCrZr alloy tubes and 316L tubes in fusion devices. This is because the diameter of CuCrZr alloy tubes and 316L tubes in fusion devices is small (e.g., 15mm) and the wall thickness is thin (e.g., 1.5mm), which cannot withstand the pressure. Meanwhile, research on high-energy welding (electron beam and laser welding) mainly focuses on welding titanium alloys or other materials.

[0004] Currently, the CuCrZr alloy tubes and 316L tubes in fusion devices have small diameters and thin walls, which places extremely high demands on the quality of weld formation and the control of weld reinforcement. A welding process is urgently needed to solve these problems. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to provide a welding structure for CuCrZr tubes and 316L tubes in a fusion device, which can ensure joint strength, weld formation quality, control the internal weld reinforcement without affecting the internal cooling channels, and achieve high welding efficiency.

[0006] According to a first aspect of the present invention, the CuCrZr tube and 316L tube welding structure of the fusion device includes a nickel-chromium-molybdenum alloy tube, a CuCrZr tube, and a 316L tube; one end of the nickel-chromium-molybdenum alloy tube and one end of the CuCrZr tube, as well as the other end of the nickel-chromium-molybdenum alloy tube and one end of the 316L tube, are coaxially connected by vacuum electron beam welding.

[0007] Due to the poor metallurgical compatibility and mismatched physical properties between the CuCrZr tube and the 316L tube, they are difficult to weld as dissimilar metals. However, the metallurgical compatibility and physical property matching between the nickel-chromium-molybdenum alloy and CuCrZr and 316L are far superior to the direct matching between CuCrZr and 316L. Therefore, by using the nickel-chromium-molybdenum alloy tube as an intermediate transition tube, and employing vacuum electron beam welding, the CuCrZr tube and the 316L tube are coaxially welded together. That is, one end of the nickel-chromium-molybdenum alloy tube and one end of the CuCrZr tube are coaxially connected by a vacuum electron beam weld, and the other end of the nickel-chromium-molybdenum alloy tube and one end of the 316L tube are coaxially connected by a vacuum electron beam weld. This solves the problem of welding differences between the nickel-chromium-molybdenum alloy tube and the CuCrZr tube, and between the nickel-chromium-molybdenum alloy tube and the 316L tube. This ensures joint strength, weld formation quality, and control of the internal weld reinforcement without affecting the internal cooling channels, while also achieving high welding efficiency.

[0008] In some embodiments, the nickel-chromium-molybdenum alloy tube is an Inconel 625 tube.

[0009] In some embodiments, a one-time forming weld is used to connect one end of the nickel-chromium-molybdenum alloy tube and one end of the CuCrZr tube, as well as the other end of the nickel-chromium-molybdenum alloy tube and one end of the 316L tube.

[0010] A second aspect of the present invention also proposes a method for welding CuCrZr tubes and 316L tubes in a fusion device.

[0011] A method for welding CuCrZr tubes and 316L tubes in a fusion device according to a second aspect of the present invention, used to obtain a CuCrZr tube and 316L tube welded structure in a fusion device according to a first aspect of the present invention, includes the following steps:

[0012] S1: Fabricate the nickel-chromium-molybdenum alloy tube;

[0013] S2: Make the ends of the nickel-chromium-molybdenum alloy tube, one end of the CuCrZr tube, and one end of the 316L tube flush and clean.

[0014] S3: The nickel-chromium-molybdenum alloy tube, the CuCrZr tube, and the 316L tube are coaxially mounted on a rotating fixture in the electron beam chamber, so that one end of the nickel-chromium-molybdenum alloy tube and one end of the CuCrZr tube are coaxially abutted together, and the other end of the nickel-chromium-molybdenum alloy tube and one end of the 316L tube are coaxially abutted together, and the electron beam chamber is evacuated.

[0015] S4: Electron beam spot welding is performed between one end of the nickel-chromium-molybdenum alloy tube and one end of the CuCrZr tube, and between the other end of the nickel-chromium-molybdenum alloy tube and one end of the 316L tube, respectively, to obtain spot welded tube fittings.

[0016] S5: After the positioning spot welded pipe fitting passes the inspection outside the chamber and meets the requirements, the positioning spot welded pipe fitting is installed on the rotating tooling in the electron beam chamber. The electron beam chamber is evacuated, and a weld is made between one end of the nickel-chromium-molybdenum alloy pipe and one end of the CuCrZr pipe. A weld is also made between the other end of the nickel-chromium-molybdenum alloy pipe and one end of the 316L pipe.

[0017] According to the second aspect of the present invention, the welding method for CuCrZr tubes and 316L tubes in a fusion device addresses the problem of inconsistent welding between CuCrZr and 316L tubes. Since the CuCrZr and 316L tubes have poor metallurgical compatibility and mismatched physical properties, they are considered dissimilar metals and difficult to weld. However, the nickel-chromium-molybdenum alloy (NiCrMo) has significantly better metallurgical compatibility and physical property matching with CuCrZr and 316L than the direct matching between CuCrZr and 316L. Therefore, by fabricating the NiCrMo alloy tube as an intermediate transition tube and coaxially welding it between the CuCrZr and 316L tubes using vacuum electron beam welding, the problem of welding differences between the NiCrMo alloy tube and the CuCrZr tube, and between the NiCrMo alloy tube and the 316L tube, is solved. This method ensures joint strength, weld formation quality, and allows control of the weld reinforcement without affecting the internal cooling channels, while also achieving high welding efficiency.

[0018] In some embodiments, in step S2, the ends of the nickel-chromium-molybdenum alloy tube, one end of the CuCrZr tube, and one end of the 316L tube are first machined to be flush, and then the ends of the nickel-chromium-molybdenum alloy tube, one end of the CuCrZr tube, and one end of the 316L tube are cleaned and wiped with a lint-free cloth.

[0019] In some embodiments, during step S2, if unevenness or burrs are found at the ends of the nickel-chromium-molybdenum alloy tube, one end of the CuCrZr tube, or one end of the 316L tube during the wiping process, a file is used for grinding.

[0020] In some embodiments, in step S3, before vacuuming, the misalignment between one end of the nickel-chromium-molybdenum alloy tube and one end of the CuCrZr tube, as well as between the other end of the nickel-chromium-molybdenum alloy tube and one end of the 316L tube, is required to be no more than 0.1 mm.

[0021] In some embodiments, in step S3, there are no gaps between the end of the nickel-chromium-molybdenum alloy tube and the end of the CuCrZr tube, and between the end of the nickel-chromium-molybdenum alloy tube and the end of the 316L tube.

[0022] In some embodiments, during step S3, when the vacuuming is completed, the vacuum level of the electron beam chamber must meet the requirement of ≤10. -3 Pa.

[0023] In some embodiments, step S4 specifically involves: placing the nickel-chromium-molybdenum alloy tube, the CuCrZr tube, and the 316L tube flat and rotating them; using an electron gun to first spot weld between one end of the nickel-chromium-molybdenum alloy tube and one end of the CuCrZr tube along the circumferential direction at intervals; after completion, spot welding is then performed between the other end of the nickel-chromium-molybdenum alloy tube and one end of the 316L tube along the circumferential direction at intervals; or using an electron gun to first spot weld between the other end of the nickel-chromium-molybdenum alloy tube and one end of the 316L tube along the circumferential direction at intervals; after completion, spot welding is then performed between one end of the nickel-chromium-molybdenum alloy tube and one end of the CuCrZr tube along the circumferential direction at intervals.

[0024] In some embodiments, the beam current of the electron beam positioning spot welding in step S4 is 8~12mA.

[0025] In some embodiments, the welding parameters for the weld seam in step S5 are the same as the spot welding parameters in step S4.

[0026] In some embodiments, the method further includes the following steps: after step S5 is completed, the obtained CuCrZr tube and 316L tube welded structure of the fusion device is subjected to visual inspection, penetrant testing, X-ray testing, and mechanical property testing.

[0027] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0028] Figure 1This is a schematic diagram of the welding structure of CuCrZr tube and 316L tube in the fusion device of this invention embodiment;

[0029] Figure 2a This is a cross-sectional macroscopic metallographic image of the CuCrZr tube and the nickel-chromium-molybdenum alloy tube after welding in the CuCrZr tube and 316L tube welding structure of the fusion device of this invention embodiment.

[0030] Figure 2b This is another cross-sectional macroscopic metallographic image of the CuCrZr tube and the nickel-chromium-molybdenum alloy tube after welding in the CuCrZr tube and 316L tube welding structure of the fusion device of the present invention.

[0031] Figure 2c This is a cross-sectional macroscopic metallographic image of a nickel-chromium-molybdenum alloy tube and a 316L tube welded together in the CuCrZr tube and 316L tube welded structure of the fusion device of this invention.

[0032] Figure 2d This is another cross-sectional macroscopic metallographic image of the nickel-chromium-molybdenum alloy tube and the 316L tube in the CuCrZr tube and 316L tube welding structure of the fusion device of this invention embodiment;

[0033] Figure 3 This is a table showing the mechanical test results of the CuCrZr tube and 316L tube welded structure of the fusion device according to an embodiment of the present invention.

[0034] Figure Labels

[0035] 1. CuCrZr tube; 2. 316L tube; 3. Nickel-chromium-molybdenum alloy tube; 4. Vacuum electron beam weld. Detailed Implementation

[0036] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0037] The following is combined Figures 1 to 3 This invention describes the welding structure and welding method of CuCrZr tube and 316L tube in the fusion device of an embodiment of the present invention.

[0038] The first aspect of this invention proposes a welding structure between a CuCrZr tube and a 316L tube for a fusion device.

[0039] like Figure 1As shown, the CuCrZr tube and 316L tube welding structure of the fusion device according to the first aspect embodiment of the present invention includes a nickel-chromium-molybdenum alloy tube 3, a CuCrZr tube 1, and a 316L tube 2. One end of the nickel-chromium-molybdenum alloy tube 3 and one end of the CuCrZr tube 1, as well as the other end of the nickel-chromium-molybdenum alloy tube 3 and one end of the 316L tube 2, are coaxially connected by vacuum electron beam welding.

[0040] Due to the poor metallurgical compatibility and mismatched physical properties between CuCrZr tube 1 and 316L tube 2, they are difficult to weld as dissimilar metals. However, the metallurgical compatibility and physical property matching between nickel-chromium-molybdenum alloy and CuCrZr and 316L are far superior to the direct matching between CuCrZr and 316L. Therefore, by using nickel-chromium-molybdenum alloy tube 3 as an intermediate transition tube, it is coaxially welded between CuCrZr tube 1 and 316L tube 2 using vacuum electron beam welding. That is, one end of nickel-chromium-molybdenum alloy tube 3 and one end of CuCrZr tube 1 are coaxially connected by vacuum electron beam welding, and the other end of nickel-chromium-molybdenum alloy tube 3 and one end of 316L tube 2 are coaxially connected by vacuum electron beam welding. This solves the problem of welding differences between nickel-chromium-molybdenum alloy tube 3 and CuCrZr tube 1, and between nickel-chromium-molybdenum alloy tube 3 and 316L tube 2. It can ensure joint strength, weld formation quality, control the internal weld reinforcement without affecting the internal cooling channel, and has high welding efficiency.

[0041] To illustrate the weld formation quality of the CuCrZr tube and 316L tube welding structure of the fusion device according to the first aspect embodiment of the present invention Figure 2a and Figure 2b The macroscopic metallographic structure of the cross-section of CuCrZr tube 1 and nickel-chromium-molybdenum alloy tube 3 after welding is shown in the CuCrZr tube and 316L tube welding structure of the fusion device. Figure 2c and Figure 2d The cross-sectional macroscopic metallographic features of the nickel-chromium-molybdenum alloy tube 3 and the 316 tube 2 after welding in the CuCrZr tube and 316L tube welding structure of the fusion device are shown in a visually intuitive way. No welding defects were found and the weld appearance was also good. It also shows that the internal reinforcement height of the vacuum electron beam weld 4 is well controlled. Figure 3 The results of the mechanical property test of the welded structure of CuCrZr tube and 316L tube for the fusion device show that the tensile fracture location is in the base material (non-weld seam), that is, the strength of the weld joint is higher than that of the base material, which meets the actual use requirements and the tensile test is qualified.

[0042] In some embodiments, the nickel-chromium-molybdenum alloy tube 3 is an Inconel 625 tube. That is, the nickel-chromium-molybdenum alloy tube 3 is made of commercially available Inconel 625 material. Inconel 625 is a high-nickel-based alloy (Ni≥58%, containing Cr, Mo, Nb), belonging to a face-centered cubic austenitic structure, with no tendency for brittle intermetallic compound precipitation. Its metallurgical compatibility and physical property matching with CuCrZr and 316L are far superior to the direct matching between CuCrZr and 316L. Using Inconel 625 for the nickel-chromium-molybdenum alloy tube 3 better ensures joint strength and weld formation quality.

[0043] In some embodiments, a one-time forming weld is used to connect one end of the nickel-chromium-molybdenum alloy tube 3 and one end of the CuCrZr tube 1, as well as the other end of the nickel-chromium-molybdenum alloy tube 3 and one end of the 316L tube 2. This effectively controls the internal weld reinforcement without affecting the internal cooling channels, and also results in high welding efficiency.

[0044] The second aspect of the present invention provides a method for welding CuCrZr tubes and 316L tubes in a fusion device.

[0045] A method for welding CuCrZr tubes and 316L tubes in a fusion device according to a second aspect of the present invention, used to obtain a CuCrZr tube and 316L tube welded structure in a fusion device according to a first aspect of the present invention, includes the following steps:

[0046] S1: Fabricate nickel-chromium-molybdenum alloy tube 3. Specifically, the radial dimension of nickel-chromium-molybdenum alloy tube 3 is consistent with the radial dimension of CuCrZr tube 1 and 316L tube 2. For example, if the diameter of CuCrZr tube 1 and 316L tube 2 is 15mm and the wall thickness is 1.5mm, then the diameter of nickel-chromium-molybdenum alloy tube 3 is 15mm and the wall thickness is 1.5mm. The length of nickel-chromium-molybdenum alloy tube 3 can be selected as needed, such as 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, etc. The metallurgical compatibility and physical property matching between nickel-chromium-molybdenum alloy and CuCrZr and 316L are far superior to the direct matching between CuCrZr and 316L. Therefore, nickel-chromium-molybdenum alloy tube 3 is fabricated as an intermediate transition tube to be coaxially welded between CuCrZr tube 1 and 316L tube 2, ensuring joint strength and welding quality. It should be noted that the radial dimensions of the nickel-chromium-molybdenum alloy tube 3 are consistent with those of the CuCrZr tube 1 and the 316L tube 2, and the diameter can be selected in the range of 12~17mm, while the wall thickness can be selected in the range of 1.2~2mm.

[0047] S2: Make the ends of the nickel-chromium-molybdenum alloy tube 3, one end of the CuCrZr tube 1, and one end of the 316L tube 2 flush and clean. This will help ensure the joint strength and weld quality.

[0048] S3: Coaxially mount the nickel-chromium-molybdenum alloy tube 3, CuCrZr tube 1, and 316L tube 2 on a rotating fixture in the electron beam chamber, so that one end of the nickel-chromium-molybdenum alloy tube 3 and one end of the CuCrZr tube 1 are coaxially connected, and the other end of the nickel-chromium-molybdenum alloy tube 3 and one end of the 316L tube 2 are coaxially connected, thereby evacuating the electron beam chamber.

[0049] S4: Electron beam spot welding is performed between one end of the nickel-chromium-molybdenum alloy tube 3 and one end of the CuCrZr tube 1, and between the other end of the nickel-chromium-molybdenum alloy tube 3 and one end of the 316L tube 2, respectively, to obtain spot-welded pipe fittings. It should be noted that the electron beam current and welding position need to be adjusted before performing electron beam spot welding. By using electron beam spot welding, rework of the spot-welded pipe fittings is facilitated if the coaxiality, misalignment, or butt joint gap requirements are not met.

[0050] S5: After the locating spot-welded pipe fittings pass the inspection outside the chamber and meet the requirements, install them on the rotating fixture in the electron beam chamber. Evacuate the electron beam chamber and perform weld seam welding between one end of the nickel-chromium-molybdenum alloy pipe 3 and one end of the CuCrZr pipe 1. Then, perform weld seam welding between the other end of the nickel-chromium-molybdenum alloy pipe 3 and one end of the 316L pipe 2. The final result is as follows: Figure 1 The fusion device shown is a welded structure of CuCrZr tubes and 316L tubes. It should be noted that the inspection of the locating welded pipe fittings after leaving the chamber includes checking the coaxiality, misalignment, and joint gap of the nickel-chromium-molybdenum alloy tube 3, CuCrZr tube 1, and 316L tube 2.

[0051] According to the second aspect of the present invention, the welding method of CuCrZr tube and 316L tube in a fusion device solves the problem of differences in welding between the CuCrZr tube 1 and the 316L tube 2. This method ensures joint strength, weld quality, and control of weld reinforcement without affecting internal cooling channels. Furthermore, the method utilizes a nickel-chromium-molybdenum alloy tube 3 as an intermediate transition tube, coaxially welded between the CuCrZr tube 1 and the 316L tube 2 using vacuum electron beam welding. This method also ensures high welding efficiency.

[0052] To illustrate the weld formation quality of the CuCrZr tube and 316L tube welded structure of the fusion device according to the second aspect embodiment of the present invention, Figure 2 visually illustrates the macroscopic metallographic structure of the CuCrZr tube and 316L tube welded structure of the fusion device. It also shows that the internal reinforcement height of the vacuum electron beam weld 4 is well controlled, and the appearance of the vacuum electron beam weld 4 is good. Figure 3 The results of the mechanical property test of the welded structure of CuCrZr tube and 316L tube for the fusion device show that the tensile fracture location is in the base material (non-weld seam), that is, the strength of the weld joint is higher than that of the base material, which meets the actual use requirements and the tensile test is qualified.

[0053] In some embodiments, in step S2, the ends of the nickel-chromium-molybdenum alloy tube 3, one end of the CuCrZr tube 1, and one end of the 316L tube 2 are first machined to make them flush, removing burrs and other imperfections. Then, the ends of the nickel-chromium-molybdenum alloy tube 3, one end of the CuCrZr tube 1, and one end of the 316L tube 2 are cleaned with alcohol, and wiped with a lint-free cloth to remove oxide layers, oil stains, etc. This helps to ensure the joint strength and weld quality.

[0054] In some embodiments, during step S2, if unevenness or burrs are found at the ends of the nickel-chromium-molybdenum alloy tube 3, one end of the CuCrZr tube 1, or one end of the 316L tube 2 during the wiping process, a file is used to grind them down. This helps to ensure the joint strength and weld quality.

[0055] In some embodiments, in step S3, before vacuuming, the misalignment between one end of the nickel-chromium-molybdenum alloy tube 3 and one end of the CuCrZr tube 1, as well as between the other end of the nickel-chromium-molybdenum alloy tube 3 and one end of the 316L tube 2, is required to be no more than 0.1 mm. This helps to ensure joint strength and weld quality, and helps to control the internal weld reinforcement without affecting the internal cooling channels.

[0056] In some embodiments, in step S3, there are no gaps between one end of the nickel-chromium-molybdenum alloy tube 3 and one end of the CuCrZr tube 1, and between the other end of the nickel-chromium-molybdenum alloy tube 3 and one end of the 316L tube 2. This helps to ensure joint strength and weld quality.

[0057] In some embodiments, in step S3, when the vacuum is completed, the vacuum level of the electron beam chamber must meet the requirement of ≤10. -3 Pa. This effectively prevents oxidation and contamination of the weld, thus ensuring joint strength and weld quality.

[0058] In some embodiments, step S4 specifically involves: placing the nickel-chromium-molybdenum alloy tube 3, the CuCrZr tube 1, and the 316L tube 2 flat and rotating them; using an electron gun to first spot weld along the circumferential interval between one end of the nickel-chromium-molybdenum alloy tube 3 and one end of the CuCrZr tube 1; after completion, spot welding along the circumferential interval between the other end of the nickel-chromium-molybdenum alloy tube 3 and one end of the 316L tube 2; or using an electron gun to first spot weld along the circumferential interval between the other end of the nickel-chromium-molybdenum alloy tube 3 and one end of the 316L tube 2; after completion, spot welding along the circumferential interval between one end of the nickel-chromium-molybdenum alloy tube 3 and one end of the CuCrZr tube 1.

[0059] In some embodiments, the beam current of the electron beam positioning spot welding in step S4 is 8~12mA, which is beneficial to ensure the joint strength and weld quality.

[0060] Specifically, the electron beam positioning spot welding parameters are as follows: the electron gun power is rated at 6~8kW, the accelerating voltage is 56~60kV, the beam current is 8~12mA, the beam current is DC deflected, the frequency is 50Hz, and the working distance is 90~95mm, where the working distance is the distance between the electron gun and the welding position. Preferably, the electron beam positioning spot welding parameters are as follows: the electron gun power is rated at 6kW, the accelerating voltage is 58kV, the beam current is 8~12mA, the beam current is DC deflected, the frequency is 50Hz, and the working distance is 92mm.

[0061] In some embodiments, the welding parameters in step S5 are consistent with the spot welding parameters in step S4, which helps to ensure joint strength and weld quality.

[0062] In some embodiments, the method further includes the following steps: after step S5 is completed, the obtained CuCrZr tube and 316L tube welded structure of the fusion device is subjected to visual inspection, penetrant and X-ray detection, and mechanical property testing to ensure the reliable operation of the CuCrZr tube and 316L tube welded structure of the fusion device in the fusion device.

[0063] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A welding structure of CuCrZr tube and 316L tube for a fusion device, characterized in that, It includes a nickel-chromium-molybdenum alloy tube, a CuCrZr tube, and a 316L tube; one end of the nickel-chromium-molybdenum alloy tube and one end of the CuCrZr tube, as well as the other end of the nickel-chromium-molybdenum alloy tube and one end of the 316L tube, are coaxially connected by vacuum electron beam welding.

2. The CuCrZr tube and 316L tube welding structure of the fusion device according to claim 1, characterized in that, The nickel-chromium-molybdenum alloy tube is an Inconel 625 tube.

3. The CuCrZr tube and 316L tube welding structure of the fusion device according to claim 1, characterized in that, The nickel-chromium-molybdenum alloy tube is connected to one end of the CuCrZr tube and the other end of the nickel-chromium-molybdenum alloy tube to one end of the 316L tube by a one-time forming weld.

4. A method for welding CuCrZr tubes and 316L tubes in a fusion device, characterized in that, The method for obtaining the CuCrZr tube and 316L tube welded structure of the fusion device as described in any one of claims 1 to 3 includes the following steps: S1: Fabricate the nickel-chromium-molybdenum alloy tube; S2: Make the ends of the nickel-chromium-molybdenum alloy tube, one end of the CuCrZr tube, and one end of the 316L tube flush and clean. S3: The nickel-chromium-molybdenum alloy tube, the CuCrZr tube, and the 316L tube are coaxially mounted on a rotating fixture in the electron beam chamber, so that one end of the nickel-chromium-molybdenum alloy tube and one end of the CuCrZr tube are coaxially abutted together, and the other end of the nickel-chromium-molybdenum alloy tube and one end of the 316L tube are coaxially abutted together, and the electron beam chamber is evacuated. S4: Electron beam spot welding is performed between one end of the nickel-chromium-molybdenum alloy tube and one end of the CuCrZr tube, and between the other end of the nickel-chromium-molybdenum alloy tube and one end of the 316L tube, respectively, to obtain spot welded tube fittings. S5: After the positioning spot welded pipe fitting passes the inspection outside the chamber and meets the requirements, the positioning spot welded pipe fitting is installed on the rotating tooling in the electron beam chamber. The electron beam chamber is evacuated, and a weld is made between one end of the nickel-chromium-molybdenum alloy pipe and one end of the CuCrZr pipe. A weld is also made between the other end of the nickel-chromium-molybdenum alloy pipe and one end of the 316L pipe.

5. The method for welding CuCrZr tubes and 316L tubes in a fusion device according to claim 4, characterized in that, In step S2, the ends of the nickel-chromium-molybdenum alloy tube, one end of the CuCrZr tube, and one end of the 316L tube are first machined to be flush. Then, the ends of the nickel-chromium-molybdenum alloy tube, one end of the CuCrZr tube, and one end of the 316L tube are cleaned and wiped with a lint-free cloth.

6. The method for welding CuCrZr tubes and 316L tubes in a fusion device according to claim 5, characterized in that, In step S2, if unevenness or burrs are found at the ends of the nickel-chromium-molybdenum alloy tube, one end of the CuCrZr tube, or one end of the 316L tube during the wiping process, a file is used to grind them.

7. The method for welding CuCrZr tubes and 316L tubes in a fusion device according to claim 4, characterized in that, In step S3, before vacuuming, the misalignment between one end of the nickel-chromium-molybdenum alloy tube and one end of the CuCrZr tube, as well as between the other end of the nickel-chromium-molybdenum alloy tube and one end of the 316L tube, is required to be no more than 0.1 mm.

8. The method for welding CuCrZr tubes and 316L tubes in a fusion device according to claim 7, characterized in that, In step S3, there are no gaps between the end of the nickel-chromium-molybdenum alloy tube and the end of the CuCrZr tube, and between the end of the nickel-chromium-molybdenum alloy tube and the end of the 316L tube.

9. The method for welding CuCrZr tubes and 316L tubes in a fusion device according to claim 8, characterized in that, In step S3, when the vacuum is completed, the vacuum level of the electron beam chamber must meet the requirement of ≤10. -3 Pa.

10. The method for welding CuCrZr tubes and 316L tubes in a fusion device according to claim 4, characterized in that, Step S4 specifically involves: placing the nickel-chromium-molybdenum alloy tube, the CuCrZr tube, and the 316L tube flat and rotating them; using an electron gun, first spot welding is performed circumferentially between one end of the nickel-chromium-molybdenum alloy tube and one end of the CuCrZr tube; after completion, spot welding is performed circumferentially between the other end of the nickel-chromium-molybdenum alloy tube and one end of the 316L tube; or, using an electron gun, first spot welding is performed circumferentially between the other end of the nickel-chromium-molybdenum alloy tube and one end of the 316L tube; after completion, spot welding is performed circumferentially between one end of the nickel-chromium-molybdenum alloy tube and one end of the CuCrZr tube.

11. The method for welding CuCrZr tubes and 316L tubes in a fusion device according to claim 10, characterized in that, The electron beam current for spot welding in step S4 is 8~12mA.

12. The method for welding CuCrZr tubes and 316L tubes in a fusion device according to any one of claims 4 to 10, characterized in that, The welding parameters for the weld seam in step S5 are the same as those for the spot welding in step S4.

13. The method for welding CuCrZr tubes and 316L tubes in a fusion device according to any one of claims 4 to 10, characterized in that, The process also includes the following steps: After step S5 is completed, the obtained CuCrZr tube and 316L tube welded structure of the fusion device is subjected to visual inspection, penetrant testing, X-ray testing, and mechanical property testing.

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