Combined vacuum electron beam welding tip device

Abstract

The present application belongs to the field of nuclear power technology, and particularly relates to a combined vacuum electron beam welding head device. The device is a conical structure with a central through hole, and comprises a copper alloy base, a copper gasket and a stainless steel head. The stainless steel head is axially provided with a central through hole, and the copper alloy base is radially provided with an exhaust hole. The stainless steel head, the copper gasket and the copper alloy base are fixed together through a spiral structure. The stainless steel head is axially provided with a central through hole which is wide at the outside and narrow at the inside. The copper alloy base is axially provided with a hole. The hole is internally threaded. The present application is suitable for fuel rod electron beam welding work.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power technology, specifically relating to a combined vacuum electron beam welding mandrel device. Background Technology

[0002] Fuel rod circumferential welding is a welding method that involves placing fuel rods in a high-vacuum electron beam welding device and using the heat generated by the converged high-speed electron beam bombarding the joint between the fuel rod cladding tube and the end plug to fuse the weld. Because the welding process takes place in a high vacuum, the fuel rods cannot be cooled by thermal radiation. To ensure the smooth progress of the fuel rod circumferential welding process, high-temperature resistant and thermally conductive components need to be installed inside the vacuum electron beam welding device to ensure rapid cooling of the fuel rods after welding.

[0003] The electron beam welding mandrel is a key component in the electron beam welding process, responsible for both positioning and cooling the fuel rods. Copper alloys, due to their excellent heat dissipation properties, are often used as mandrel materials in electron beam welding. However, after electron beam welding, the high temperatures cause copper alloys to easily adhere to the contact area between the fuel rod and the mandrel. Excessive copper adhesion significantly affects the welding quality and, consequently, the yield. Stainless steel mandrels, with their higher hardness, do not adhere to the fuel rods after electron beam welding, but their poor heat dissipation severely impacts welding efficiency. Currently, there is a need to develop an electron beam welding mandrel with good heat dissipation that also prevents copper alloy adhesion to the fuel rods. Summary of the Invention

[0004] The purpose of this invention is to provide a combined vacuum electron beam welding mandrel device, suitable for electron beam welding of fuel rods.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A combined vacuum electron beam welding mandrel device is a conical structure with a central through hole, including a copper alloy base, a copper gasket, and a stainless steel mandrel. The stainless steel mandrel has a central through hole arranged axially, and the copper alloy base has an exhaust hole arranged radially. The stainless steel mandrel, copper gasket, and copper alloy base are fixed together by a spiral structure.

[0007] The stainless steel mandrel has a central through hole that is wider on the outside and narrower on the inside, which is axially oriented.

[0008] The copper alloy base has holes arranged axially.

[0009] The hole has threads.

[0010] The copper alloy base, copper gasket, and stainless steel top are clamped by the toothed tip in the round hole at the top of the copper alloy base through the threaded protrusion, which causes radial displacement and helical movement inside the copper alloy base, making it tightly connected to the copper alloy base.

[0011] During the welding process, the fuel rod is embedded in the stainless steel mandrel to ensure that the weld is located under the electron gun for easy welding positioning. The stainless steel mandrel drives the fuel rod to rotate and the electron beam welding machine is started at the same time to perform welding.

[0012] The top of the copper alloy base has four symmetrical grooves with threads, and the stainless steel top head rotates into the copper alloy base through the threads.

[0013] After the stainless steel mandrel is screwed into the copper alloy base, four pins are driven into the four grooves respectively, and the pins are locked into the threads of the stainless steel mandrel.

[0014] During welding, the fuel rod presses against the mandrel to determine the welding position. In the next step, the fuel rod rotates with the fixture to complete the welding process.

[0015] During the welding process, the welding heat is dissipated through heat conduction via the stainless steel mandrel, copper gasket, and copper alloy base.

[0016] The beneficial effects achieved by this invention are as follows:

[0017] The vacuum electron beam welding mandrel device provided by this invention is composed of various parts made of different materials tightly connected together by threads. Currently, the commonly used material for electron beam welding mandrel devices is copper alloy. Although copper alloy mandrel devices have good heat dissipation, they are prone to adhesion to the fuel rod contact area under high temperature, affecting the welding quality of the fuel rod. Stainless steel mandrel devices do not exhibit adhesion, but their poor heat dissipation significantly impacts welding efficiency. The combined mandrel device proposed in this invention integrates the material properties of copper alloy and stainless steel, effectively improving production efficiency and yield, and is convenient to implement with low manufacturing cost. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the combined vacuum electron beam welding mandrel device;

[0019] Figure 2 An exploded view of a combined vacuum electron beam welding mandrel device;

[0020] Figure 3 A schematic cross-sectional view of a combined vacuum electron beam welding mandrel device;

[0021] Figure 4 A schematic cross-sectional view of the copper base of a combined vacuum electron beam welding mandrel device;

[0022] Figure 5 This is a schematic diagram of the fuel rod welding process;

[0023] Figure 6 This is a schematic diagram of the overall design of the second type of combined vacuum electron beam welding mandrel device;

[0024] Figure 7 An exploded view of the second type of combined vacuum electron beam welding mandrel device;

[0025] In the diagram: 1. Stainless steel top, 2. Copper gasket, 3. Copper alloy base, 4. Center through hole, 5. Vent hole. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0027] This invention relates to a core tooling system for fuel rod welding, consisting of multiple components of different materials assembled together via a mechanical structure. The mandrel is made of stainless steel, but other high-temperature resistant metals or alloys that will not adhere to zirconium alloy tubing in direct contact can also be used. The mandrel has a central through-hole (wider on the outside, narrower on the inside) in the axial direction to facilitate surface contact with the fuel rod mandrel. The gasket is made of copper, serving as a heat transfer medium and preventing the mandrel from loosening during welding. The base is made of copper alloy, with axially oriented holes containing threads. Vent holes are provided in the radial direction.

[0028] The vacuum electron beam welding mandrel device provided by this invention is an assembled component with high overall precision and accurate positioning. The stainless steel mandrel, copper gasket, and copper alloy base at the mandrel are fixed together by a spiral structure, which provides good fixation and mechanical positioning for the fuel rod.

[0029] Example 1: As Figure 1 and 2 As shown, the electron beam welding mandrel is a conical structure with a central through hole, comprising three parts: a copper alloy base, a copper gasket, and a stainless steel mandrel. The copper alloy base has radial vent holes that run through the entire part. The stainless steel mandrel has a central through hole with an outer wider and inner narrower structure to ensure that the fuel rod and the mandrel have the smallest possible surface contact at the diameter.

[0030] The copper alloy base, copper gasket, and stainless steel top are clamped by the toothed tip in the round hole at the top of the copper alloy base through the threaded protrusion, which causes radial displacement and helical movement inside the copper alloy base, making it tightly connected to the copper base.

[0031] During welding, the fuel rod is embedded in the stainless steel mandrel to ensure the weld seam is positioned below the electron gun for easy welding positioning. The mandrel rotates the fuel rod while simultaneously starting the electron beam welder for welding. Figure 5 As shown.

[0032] The vacuum electron beam welding machine mandrel device of the present invention effectively fixes the welding position of the fuel rod end plug, resulting in minimal radial runout during fuel rod rotation. During welding, heat is dissipated through the welding components via heat conduction via the stainless steel mandrel, copper gasket, and copper alloy base. The stainless steel mandrel effectively prevents the copper alloy mandrel from adhering to the contact point with the fuel rod after being exposed to high temperatures. The welding quality using this mandrel device meets the requirements for fuel assembly.

[0033] Example 2: As Figure 6 As shown, Example 2 uses the same copper alloy base as Example 1, the difference being that the copper alloy base in Example 2 has four symmetrical grooves at its top, with threads in each groove. The stainless steel mandrel in Example 2 is the same size as that in Example 1, and it is screwed into the copper base via its threads. After the stainless steel mandrel is screwed into the copper base, four pins are driven into the four grooves, securing the mandrel in place. Thanks to the securing effect of the four pins, Example 2 does not require copper washers. The rest is the same as in Example 1.

[0034] The vacuum electron beam welding mandrel device provided by this invention is composed of components made of various materials, tightly integrated through a mechanical structure. During welding, the fuel rod presses against the mandrel device to determine the welding position. Next, the fuel rod rotates with the fixture to complete the welding process. During welding, the welding heat is dissipated through the stainless steel mandrel, copper gasket, and copper alloy base via heat conduction. This not only solves the heat dissipation problem during fuel rod welding but also effectively prevents the copper alloy material from adhering to the contact surface with the fuel rod due to high temperatures. This effectively improves fuel rod production efficiency, is easy to implement, and has low manufacturing costs.

Claims

1. A combined vacuum electron beam welding mandrel device, characterized in that: It is a conical structure with a central through hole, including a copper alloy base, a copper gasket, and a stainless steel top. The stainless steel top has an axially arranged central through hole, and the copper alloy base has a radially arranged vent hole. The stainless steel top, copper gasket, and copper alloy base are fixed together by a spiral structure.

2. The combined vacuum electron beam welding mandrel device according to claim 1, characterized in that: The stainless steel mandrel has a central through hole that is wider on the outside and narrower on the inside, which is axially oriented.

3. The combined vacuum electron beam welding mandrel device according to claim 1, characterized in that: The copper alloy base has holes set along its axis.

4. The combined vacuum electron beam welding mandrel device according to claim 3, characterized in that: The hole has threads.

5. The combined vacuum electron beam welding mandrel device according to claim 1, characterized in that: The copper alloy base, copper gasket, and stainless steel top are clamped by the toothed tip in the round hole at the top of the copper alloy base through the threaded protrusion, which causes radial displacement and helical movement inside the copper alloy base, making it tightly connected to the copper alloy base.

6. The combined vacuum electron beam welding mandrel device according to claim 1, characterized in that: During the welding process, the fuel rod is embedded in the stainless steel mandrel to ensure that the weld is located under the electron gun for easy welding positioning. The stainless steel mandrel drives the fuel rod to rotate and the electron beam welding machine is started at the same time to perform welding.

7. The combined vacuum electron beam welding mandrel device according to claim 1, characterized in that: The top of the copper alloy base has four symmetrical grooves with threads, and the stainless steel top head rotates into the copper alloy base through the threads.

8. The combined vacuum electron beam welding mandrel device according to claim 7, characterized in that: After the stainless steel mandrel is screwed into the copper alloy base, four pins are driven into the four grooves respectively, and the pins are locked into the threads of the stainless steel mandrel.

9. The combined vacuum electron beam welding mandrel device according to claim 1, characterized in that: During welding, the fuel rod presses against the mandrel to determine the welding position. In the next step, the fuel rod rotates with the fixture to complete the welding process.

10. The combined vacuum electron beam welding mandrel device according to claim 1, characterized in that: During the welding process, the welding heat is dissipated through the stainless steel mandrel, copper gasket, and copper alloy base via heat conduction.

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