Weld joint shape righting device and welding method for related rods of fixed related components

Abstract

The invention belongs to the technical field of manufacturing of nuclear fuel elements for nuclear power stations, and particularly relates to a weld joint shape righting device and a welding method for related rods of fixed related assemblies. The base and the fixed wheel shell are fixed together; the base is connected with the shape righting wheel shell through a positioning pin, and the shape righting wheel shell can rotate around the positioning pin; the base and the orthopedic wheel connecting rod are connected together, the orthopedic wheel connecting rod can be driven to axially move along a guide hole of the base by rotating the rotating handle, two fixed wheels are arranged on the fixed wheel shell, the relative positions between the two fixed wheels and between the two fixed wheels and the base are fixed, and the two fixed wheels can rotate around the positioning pin. A movable wheel is arranged on the shape righting wheel shell, the movable wheel can rotate around a positioning pin and can also rotate relative to the base along with the shape righting wheel shell, the shape righting wheel connecting rod is driven to move axially by rotating the rotating handle, then the shape righting wheel shell is driven to rotate, and the movable wheel is driven to move relative to the base. The technical problem of welding manufacturing of domestic related rods is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of manufacturing nuclear fuel elements for nuclear power plants, and in particular relates to a weld correction device and a welding method for fixed-type related component related rods. Background Art

[0002] Fixed related components are related components for million-kilowatt nuclear power units designed independently in China. Related rods are important components of fixed related components, including neutron source rods, burnable poison rods, etc. The related rods have similar structures, including upper end plugs, lower end plugs, cladding tubes, core materials, etc. The welding materials of the related rods are the same, all of which are made of domestic stainless steel.

[0003] The welding process of the relevant rods includes the plugging process, the girth welding process, the weld correction process, etc. Among them, the girth welding of the relevant rods adopts the TIG welding method, and welding defects such as cracks are prone to occur during the welding process. In addition, the girth weld protrudes from the surface of the cladding tube, causing the ring gauge of the weld to not pass smoothly, which does not meet the requirements of the technical conditions. Therefore, it is necessary to determine the welding method of the relevant rods and design a device for weld correction to achieve the welding and correction of the relevant rods. At present, except for our company, there is no welding and correction method for the relevant rods in China, and there is no relevant report on the welding and correction method for the relevant rods abroad. Summary of the invention

[0004] The purpose of the present invention is to provide a fixed type related component related rod weld correction device and welding method, to solve the manufacturing technology difficulties of welding of domestic related rods, and to solve the problem that after the related rod cladding tube and the end plug are welded, the weld ring gauge cannot pass smoothly through the weld of the related rod.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A weld orthopedic device with fixed related components and related rods, wherein a base is fixed to a fixed wheel shell; the base and the orthopedic wheel shell are connected together by a locating pin, and the orthopedic wheel shell can rotate around the locating pin; the base is connected to an orthopedic wheel connecting rod, and the orthopedic wheel connecting rod can be driven to move axially along a guide hole of the base by rotating a rotating handle; two fixed wheels are arranged on the fixed wheel shell, and the relative positions between the two fixed wheels and between the two fixed wheels and the base are fixed, and the two fixed wheels can rotate around the locating pin; a movable wheel is arranged on the orthopedic wheel shell, and in addition to being able to rotate around the locating pin, the movable wheel can also rotate relative to the base with the orthopedic wheel shell, and the orthopedic wheel connecting rod is driven to move axially by rotating the rotating handle, thereby driving the orthopedic wheel shell to rotate, and driving the movable wheel to move relative to the base.

[0007] The base is welded and fixed to the fixed wheel shell.

[0008] The base and the orthopedic wheel connecting rod are connected together through threads.

[0009] The relevant rods that need to be corrected are placed between the two fixed wheels to achieve positioning; the rotating handle is turned to drive the correction wheel connecting rod to move axially along the guide hole of the base; the correction wheel connecting rod drives the correction wheel shell to move axially, thereby allowing the movable wheel to clamp the relevant rods that need to be corrected.

[0010] There can be no relative movement between the base and the fixed wheel housing.

[0011] A method for welding related rods of fixed related components,

[0012] Step 1: Use a turning tool to locate and cut off the relevant rod cladding tube and remove the burrs;

[0013] Step 2: Grinding the inner wall of the cladding tube mouth;

[0014] Step 3: After the end plug is cleaned, there is no stain on the surface. Place the cladding tube on the cleaning table and wipe the inner wall of the nitriding tube with a cotton swab or silk cloth dipped in acetone, and wipe the end face and outer wall of the nitriding tube with a silk cloth dipped in acetone;

[0015] Step 4: Press the relevant rod end plug into the relevant rod cladding tube;

[0016] Step 5: Welding: Open the argon gas and compressed air pipeline valves to put the welder into the pre-welding state; set the welding process parameters for welding;

[0017] Step 6: If the weld of the relevant rod cannot pass through the 9.82mm ring gauge smoothly, the weld of the relevant rod needs to be corrected. The weld correction device is placed around the relevant rod that needs to be corrected. The handle is slightly turned to make the movable wheel apply a small clamping force to the relevant rod that needs to be corrected. The weld correction device is slowly rotated 360° circumferentially for correction, so that the protruding shape of the weld of the relevant rod is uniform and reaches the outer diameter of the relevant cladding, ensuring that the outer diameter of the weld can pass the weld ring gauge smoothly.

[0018] Step 1: The maximum chamfer of the outer tube mouth is 0.05mm; the maximum chamfer of the inner tube mouth is 0.05mm×0.13mm. After cutting the tube, check the appearance and size of the cladding tube to meet the requirement of inner diameter ≥Ф8.72mm; Step 2: Use 400-grit metallographic sandpaper to grind the inner wall of the cladding tube mouth.

[0019] The welds of the relevant rods are X-ray inspected to meet the following conditions: a) The weld penetration is not less than 90% of the minimum theoretical wall thickness of the pipe, which is 0.43mm; b) The remaining wall thickness of the pipe due to gas expansion is not less than 90% of the minimum theoretical wall thickness of the pipe, which is 0.43mm; c) Inclusions or pores with a diameter not greater than 0.25mm are allowed; The relevant rods are helium leak tested, and the leakage rate is less than 10 -9 Pa·m3 / s; There are no scratches, bumps or pits on the surface of the relevant rods, and the length and runout meet the technical requirements.

[0020] Use a cotton swab or silk cloth dipped in acetone to wipe the inner wall of the nitriding tube, with a wiping depth of at least 10mm from the tube end face; use a silk cloth dipped in acetone to wipe the end face and outer wall of the nitriding tube, with a wiping depth of at least 50mm from the tube end face.

[0021] Step 4: The plugging force is controlled at 0.2-0.3Mpa. Visually check that the gap between the cladding tube and the end plug is less than 0.1mm. Check the ovality of the clamping part of the cladding tube, which should be controlled within 0.05mm. Step 5: The welding electrode is cerium tungsten Ce-W; the electrode diameter is Φ2.0mm; the electrode taper is 30°; the cooling time is ≥5s; the welding speed is 12r / min; the welding time is 8s; the welding current is 54A±1A; the inter-electrode spacing is 0.5mm-0.8mm; the electrode deviates from the weld center by -0.1mm-0.2mm. The oxidation color on the weld surface is polished and removed with an ultra-clean scouring pad. Grinding of the pipe wall outside the welding area is not allowed. A ring gauge with a diameter of Ф9.82mm and a length of 20mm should pass freely through the weld of the end plug. Visually check that the weld has no oxidation color exceeding the technical requirements.

[0022] The beneficial effects achieved by the present invention are:

[0023] The present invention is applied to the welding of domestic fixed related component related rods for the first time. The determined welding method and designed weld correction device realize the welding and correction of domestic related rods. The method has been applied to the batch production of the related rods, and the various test quantity data are in line with expectations. The batch of related rods have been put into operation with good results. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the weld correction device;

[0025] Figure 2 It is a schematic diagram of the correction of the relevant rod weld;

[0026] 1-fixed wheel; 2-movable wheel; 3-base; 4-rotating handle; 5-fixed wheel housing; 6-orthopedic wheel housing; 7-orthopedic wheel connecting rod. DETAILED DESCRIPTION

[0027] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] The fixed related rod is composed of an upper end plug, a lower end plug, a core material, and a cladding tube. The end plug of the related rod is connected to the cladding tube by TIG welding. The welding material of the related rod is domestic stainless steel, the material of the end plug is 022Cr21Ni10, and the material of the cladding tube is 06Cr19Ni10. Its welding process includes plugging process, girth welding process, weld correction, etc. Among them, the girth welding process adopts TIG welding. In addition to the common defects such as pores and incomplete penetration, there is also a crack defect, which is the most dangerous defect and will seriously weaken the strength of the material.

[0029] The defects such as pores and cracks produced by the relevant rod ring welding are analyzed, and the measures to overcome the welding defects are as follows: After cutting the cladding tube mouth, wipe the inside and outside of the tube with acetone, and polish it with sandpaper when necessary to ensure the cleanliness of the cladding tube mouth. Remove the oxide layer on the inner and outer surfaces of the cladding tube to reduce inclusions; reduce the welding speed to slow down the crystallization speed to reduce the restraining stress; reduce the welding current to reduce the melting zone area to reduce the shrinkage stress.

[0030] The structure of the related rod welding orthopedic device is that the base 3 of the welding orthopedic tool is welded and fixed to the fixed wheel shell 5, and the two cannot move relative to each other; the base 3 is connected to the orthopedic wheel shell 6 by a locating pin, and the orthopedic wheel shell 6 can rotate around the locating pin; the base 3 is connected to the orthopedic wheel connecting rod 7 by a thread, and the orthopedic wheel connecting rod 7 can be driven to move axially along the guide hole of the base 3 by rotating the rotating handle 4. Two fixed wheels 1 are arranged on the fixed wheel shell 5. The relative positions between the two fixed wheels 1 and between the two fixed wheels 1 and the base 3 are fixed, and the two fixed wheels 1 can rotate around the locating pin. A movable wheel 2 is arranged on the orthopedic wheel shell 6. In addition to rotating around the locating pin, the movable wheel 2 can also rotate relative to the base 3 with the orthopedic wheel shell 6. By rotating the rotating handle 4, the orthopedic wheel connecting rod 7 is driven to move axially, and then the orthopedic wheel shell 6 is driven to rotate, and the movable wheel 2 is driven to move relative to the base 3. When the welding seam correction tool is operated, the relevant rod (or workpiece) to be corrected is placed between the two fixed wheels 1 to realize the positioning of the workpiece; the rotating handle 4 is rotated to drive the correction wheel connecting rod 7 to move axially along the guide hole of the base 3; the correction wheel connecting rod 7 drives the correction wheel housing 6 to move axially, thereby making the movable wheel 2 clamp the pipe fitting to be corrected;

[0031] Related rod welding process flow: cladding tube cutting → cladding tube grinding → tube mouth cleaning → end plug pressing → end plug annular seam welding → weld correction (if necessary) → X-ray inspection → helium mass spectrometer leak detection → appearance and size inspection.

[0032] The implementation steps are as follows:

[0033] Step 1: Cutting the relevant rod cladding tube

[0034] Use a turning tool to cut the cladding tube and remove burrs. The maximum chamfer of the tube mouth is 0.05mm; the maximum chamfer of the tube mouth is 0.05mm×0.13mm. After cutting the tube, the appearance and size of the cladding tube should be checked to meet the requirement of inner diameter ≥Ф8.72mm.

[0035] Step 2: Polishing the pipe mouth

[0036] After cutting the tube, use 400-grit metallographic sandpaper to grind the inner wall of the cladding tube.

[0037] Step 3: Parts cleaning

[0038] The end plug has been cleaned and there is no stain on the surface. Wipe the inner wall of the nitriding tube with a cotton swab or silk cloth dipped in acetone on the cleaning table, and the wiping depth should be at least 10mm from the tube end face; wipe the end face and outer wall of the nitriding tube with a silk cloth dipped in acetone, and the wiping depth should be at least 50mm from the tube end face.

[0039] Step 4: Plug the relevant rods

[0040] Press the relevant rod end plug into the relevant rod cladding tube, and control the plugging force to 0.2-0.3Mpa. Visually check that the gap between the cladding tube and the end plug is less than 0.1mm. Check the ovality of the clamping part of the cladding tube, which should be controlled within 0.05mm.

[0041] Step 5: Soldering

[0042] Open the valves of argon and compressed air pipelines to make the welder enter the pre-welding state; set the welding process parameters for welding. The welding electrode is cerium tungsten Ce-W; the electrode diameter is Φ2.0mm; the electrode taper is 30°; the main welding process parameters are as follows: cooling time ≥5s; welding speed 12r / min; welding time 8s; welding current 54A±1A; inter-electrode spacing 0.5mm~0.8mm; the electrode deviates from the weld center -0.1mm~0.2mm. The oxidation color on the weld surface is polished and removed with an ultra-clean scouring pad (the main components are nylon fiber, polymer fiber, and corundum), and polishing of the pipe wall outside the welding area is not allowed. A ring gauge with a diameter of Ф9.82mm and a length of 20mm should pass freely through the weld of the end plug. Visually inspect the weld to see if there is no oxidation color that exceeds the technical requirements.

[0043] Step 6: Correction of the relevant rod weld

[0044] If the weld of the relevant rod cannot pass the 9.82mm ring gauge smoothly, the weld of the relevant rod needs to be corrected. The weld correction device is placed around the relevant rod that needs to be corrected. According to the needs of the workpiece, continue to slightly turn the handle 4 so that the movable wheel 2 applies a slight pressure / clamping force to the pipe that needs to be corrected. The weld correction device slowly rotates 360° circumferentially to correct the weld convex shape of the relevant rod to be uniform. Reach the outer diameter of the relevant cladding. Ensure that the outer diameter of the weld can pass the weld ring gauge smoothly.

[0045] The relevant rod welds are X-ray inspected to meet the following conditions:

[0046] a) The weld penetration depth should not be less than 90% of the minimum theoretical wall thickness of the pipe (0.43mm);

[0047] b) The remaining wall thickness of the pipe due to inflation is not less than 90% of the minimum theoretical wall thickness of the pipe (0.43 mm);

[0048] c) Inclusions or pores with a diameter not exceeding 0.25 mm are allowed;

[0049] The relevant rods are tested for helium leaks; the leakage rate should be less than 10 -9 Pa·m3 / s.

[0050] The surface of the relevant rods shall be free of scratches, dents and pits. The length and runout shall meet the technical requirements.

Claims

1. A weld correction device for fixed related components and related rods, characterized in that: The base is fixed to the fixed wheel shell; the base is connected to the orthopedic wheel shell through a locating pin, and the orthopedic wheel shell can rotate around the locating pin; the base is connected to the orthopedic wheel connecting rod, and the orthopedic wheel connecting rod can be driven to move axially along the guide hole of the base by rotating the rotating handle. Two fixed wheels are arranged on the fixed wheel shell, and the relative positions between the two fixed wheels and between the two fixed wheels and the base are fixed. The two fixed wheels can rotate around the locating pin. A movable wheel is arranged on the orthopedic wheel shell. In addition to rotating around the locating pin, the movable wheel can also rotate relative to the base with the orthopedic wheel shell. The orthopedic wheel connecting rod is driven to move axially by rotating the rotating handle, thereby driving the orthopedic wheel shell to rotate and driving the movable wheel to move relative to the base.

2. The weld correction device of the fixed related component related rod according to claim 1 is characterized in that: The base is welded and fixed to the fixed wheel shell.

3. The weld correction device of the fixed-type related component and related rod according to claim 1 is characterized in that: The base and the orthopedic wheel connecting rod are connected together through threads.

4. The weld correction device of the fixed related component related rod according to claim 1, characterized in that: The relevant rods that need to be corrected are placed between the two fixed wheels to achieve positioning; the rotating handle is turned to drive the correction wheel connecting rod to move axially along the guide hole of the base; the correction wheel connecting rod drives the correction wheel shell to move axially, thereby allowing the movable wheel to clamp the relevant rods that need to be corrected.

5. The weld correction device of the fixed-type related component and related rod according to claim 1, characterized in that: There can be no relative movement between the base and the fixed wheel housing.

6. A method for welding related rods of fixed related components, characterized in that: Step 1: Use a turning tool to locate and cut off the relevant rod cladding tube and remove the burrs; Step 2: Grinding the inner wall of the cladding tube mouth; Step 3: After the end plug is cleaned, there is no stain on the surface. Place the cladding tube on the cleaning table and wipe the inner wall of the nitriding tube with a cotton swab or silk cloth dipped in acetone, and wipe the end face and outer wall of the nitriding tube with a silk cloth dipped in acetone; Step 4: Press the relevant rod end plug into the relevant rod cladding tube; Step 5: Welding: Open the argon gas and compressed air pipeline valves to put the welder into the pre-welding state; set the welding process parameters for welding; Step 6: If the weld of the relevant rod cannot pass through the 9.82mm ring gauge smoothly, the weld of the relevant rod needs to be corrected. The weld correction device is placed around the relevant rod that needs to be corrected. The handle is slightly turned to make the movable wheel apply a small clamping force to the relevant rod that needs to be corrected. The weld correction device is slowly rotated 360° circumferentially for correction, so that the protruding shape of the weld of the relevant rod is uniform and reaches the outer diameter of the relevant cladding, ensuring that the outer diameter of the weld can pass the weld ring gauge smoothly.

7. The method for welding related rods of fixed related components according to claim 6, characterized in that: Step 1: The maximum chamfer of the outer tube mouth is 0.05mm; the maximum chamfer of the inner tube mouth is 0.05mm×0.13mm. After cutting the tube, check the appearance and size of the cladding tube to meet the requirement of inner diameter ≥Ф8.72mm; Step 2: Use 400-grit metallographic sandpaper to grind the inner wall of the cladding tube mouth.

8. The method for welding related rods of fixed related components according to claim 6, characterized in that: The welds of the relevant rods are X-ray inspected to meet the following conditions: a) The weld penetration is not less than 90% of the minimum theoretical wall thickness of the pipe, which is 0.43mm; b) The remaining wall thickness of the pipe due to gas expansion is not less than 90% of the minimum theoretical wall thickness of the pipe, which is 0.43mm; c) Inclusions or pores with a diameter not greater than 0.25mm are allowed; The relevant rods are helium leak tested, and the leakage rate is less than 10 -9 Pa·m3 / s; There are no scratches, bumps or pits on the surface of the relevant rods, and the length and runout meet the technical requirements.

9. The method for welding related rods of fixed related components according to claim 6, characterized in that: Use a cotton swab or silk cloth dipped in acetone to wipe the inner wall of the nitriding tube, with a wiping depth of at least 10mm from the tube end face; use a silk cloth dipped in acetone to wipe the end face and outer wall of the nitriding tube, with a wiping depth of at least 50mm from the tube end face.

10. The method for welding related rods of fixed related components according to claim 6, characterized in that: Step 4: The plugging force is controlled at 0.2-0.3Mpa, and the gap between the cladding tube and the end plug is visually checked to be less than 0.1mm. The ovality of the clamping part of the cladding tube is checked and should be controlled within 0.05mm; Step 5: The welding electrode is cerium tungsten Ce-W; the electrode diameter is Φ2.0mm; the electrode taper is 30°; the cooling time is ≥5s; Welding speed 12r / min; welding time 8s; welding current 54A±1A; inter-electrode spacing 0.5mm~0.8mm; The electrode deviates from the weld center by -0.1mm~0.2mm. The oxidation color on the weld surface is polished away with an ultra-clean scouring pad. Polishing of the pipe wall outside the welding area is not allowed. A ring gauge with a diameter of Ф9.82mm and a length of 20mm should pass freely through the weld of the end plug. Visual inspection of the weld shows that there is no oxidation color exceeding that specified in the technical conditions.

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