Low-temperature TIG (Tungsten Inert Gas) welding clamping device and method for small-wall-thickness base body and end plug

Abstract

The invention discloses a low-temperature TIG (Tungsten Inert Gas) welding clamping device and method for a small-wall-thickness base body and an end plug, relates to the technical field of nuclear fuel welding, and is used for solving the problem that surface defects such as fusion sinking are easily generated in the welding process of an existing small-wall-thickness base body hole wall and the end plug. The device comprises a lower supporting piece arranged on a fixed base, a base body can be horizontally placed on the lower supporting piece and can be supported by the lower supporting piece, an upper supporting piece is rotationally connected to the lower supporting piece and has the opening, closing and rotating functions, and the upper supporting piece and the lower supporting piece are consistent with the outer contour size of the base body and are locked through fastening bolts; and assembling, clamping and fastening of the base body can be achieved. The method for welding the base body and the end plug through the device comprises the four steps of welding workpiece cleaning, base body assembling, end plug assembling and welding. By means of the device and the welding method, the problems of horizontal fixing of the welding base body and plane assembling and fixing of the end plug and the base body hole are solved, and good welding between the small-wall-thickness base body hole wall and the end plug is achieved.

Description

Technical Field

[0001] This invention belongs to the field of nuclear fuel welding technology, specifically relating to a low-temperature TIG welding clamping device and method for thin-walled substrates and end plugs. Background Technology

[0002] 316Ti stainless steel is a commonly used structural material in the nuclear fuel field, generally used in critical components such as cladding or fuel matrix. Currently, electron beam welding or TIG welding is commonly used for welding 316Ti materials. However, with the thin wall thickness design of the 316Ti porous fuel matrix (minimum wall thickness between adjacent holes ≤ 1.7mm), electron beam welding, with its high input energy, easily produces defects such as surface sinking of the matrix wall during the welding process between the hole wall and the end plug, failing to meet technical requirements. TIG welding results in a wider weld pool, which can easily affect the welds of adjacent holes during the welding process, damaging the weld surface quality. Furthermore, the welding of the end plug to the matrix is ​​a planar fillet weld structure, making assembly and fixing difficult, and assembly deviations can easily cause welding defects such as porosity and misalignment. To address the challenges of difficult assembly and easy welding sinking defects in the 316Ti thin-walled matrix holes and end plugs, this invention develops a new welding process through welding tooling design, new welding process matching, and welding parameter optimization, achieving good welding of 316Ti thin-walled matrix holes and end plugs. Summary of the Invention

[0003] The purpose of this invention is to provide a low-temperature TIG welding clamping device and method for thin-walled substrates and end plugs, which solves the problem of surface defects such as melt sink marks that are easily generated during the welding process of thin-walled substrate hole walls and end plugs.

[0004] The technical solution adopted by the present invention to solve its technical problem is: a low-temperature TIG welding clamping device for a thin-walled substrate and an end plug, wherein the device includes: a lower support member disposed on a fixed base, on which the substrate can be horizontally placed and supported, and an upper support member rotatably connected to the lower support member and having opening, closing and rotation functions. Both have the same outer contour dimensions as the substrate and are locked by fastening bolts, which can realize the assembly, clamping and fastening of the substrate.

[0005] The above-mentioned low-temperature TIG welding clamping device for a thin-walled substrate and an end plug includes an origin roller bolt on the upper and lower support members for positioning the origin of the device support structure.

[0006] The above-mentioned low-temperature TIG welding clamping device for a thin-walled substrate and an end plug, wherein one side of the upper support is connected to the same side of the lower support via a rotating shaft, and the internal contours of the two are consistent with the outer contour of the substrate.

[0007] The aforementioned low-temperature TIG welding clamping device for a thin-walled substrate and an end plug, wherein the fastening bolts are located on the non-connecting sides of the upper and lower support members.

[0008] A low-temperature TIG welding method for a thin-walled substrate to an end plug, wherein the method includes the following steps:

[0009] Step 1: Cleaning the workpieces before welding. Before welding, each part needs to be cleaned with organic solvent and then dried.

[0010] Step 2, base assembly: Open the upper support of the clamping device, place the base horizontally on the lower support, then close the upper support and lock it with the fastening bolts;

[0011] Step 3: End plug assembly. Slowly insert the end plug into the end plug welding hole on the substrate to achieve a planar fit between the end face of the end plug and the end face of the substrate.

[0012] Step 4, Welding: After assembly, pulse welding is performed on the end plug and the base body. The welding current is 100-300A and the welding time is 1-20s. After turning on the inert gas shielding gas, spot weld around the weld seam with the welding torch to complete the welding. After cooling for more than 10 minutes, turn off the inert gas shielding gas.

[0013] In the above-mentioned low-temperature TIG welding method for a thin-walled substrate and an end plug, the preferred method for cleaning the components with organic solvents before welding is ultrasonic immersion in acetone. If the size of the components to be welded is not suitable for ultrasonic immersion in acetone, the welding area is wiped with a lint-free cloth soaked in acetone.

[0014] The above-mentioned low-temperature TIG welding method for a thin-walled substrate and an end plug involves cleaning the end plug by ultrasonic immersion in acetone, with at least two immersions, each requiring replacement with fresh acetone, and each immersion lasting at least 10 minutes.

[0015] The above-mentioned low-temperature TIG welding method for a thin-walled substrate and an end plug, wherein the drying temperature of the end plug after immersion and drying is 80°C, and the drying time is greater than or equal to 20 minutes.

[0016] In the above-mentioned low-temperature TIG welding method for a thin-walled substrate and an end plug, the inert gas shielding gas is helium.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The low-temperature TIG welding clamping device and method for a thin-walled substrate and an end plug provided by the present invention, on the one hand, achieves horizontal fixation of the substrate and planar alignment and fixation of the end plug and the end face of the substrate hole through the design of welding fixtures; on the other hand, through welding process optimization, matching welding mode, and adjusting key parameters such as welding current and welding time, good welding between the thin-walled substrate hole wall and the end plug is achieved, avoiding the generation of welding defects such as melt sinkhole. Attached Figure Description

[0018] Figure 1 The diagram shown is a structural schematic of a low-temperature TIG welding clamping device for a thin-walled substrate and an end plug according to the present invention.

[0019] Figure 2 The figure shown is a cross-sectional view of the substrate held by the low-temperature TIG welding clamping device for a thin-walled substrate and an end plug according to the present invention.

[0020] Figure 3 The diagram shows the structure of the end plug in conjunction with the low-temperature TIG welding clamping device for a thin-walled substrate and an end plug according to the present invention.

[0021] The following are the symbols in the attached diagram: 1. Fixed base; 2. Origin roller bolt; 3. Upper support component; 4. Lower support component; 5. Fastening bolt; 6. Base body; 7. End plug welding hole; 8. End plug. Detailed Implementation

[0022] To address the issue of surface defects such as melt sink marks that easily occur during the welding of thin-walled substrates to end plugs, this invention provides a low-temperature TIG welding clamping device and method for thin-walled substrates to end plugs. The welding clamping device is as follows: Figures 1-3 As shown, the device includes: a lower support member 4 mounted on a fixed base 1, on which a base 6 can be horizontally placed and supported; an upper support member 3 rotatably connected to the lower support member 4, possessing opening, closing, and rotation functions; both members have the same outer contour dimensions as the base 6 and are locked together by fastening bolts 5, enabling the assembly, clamping, and fastening of the base 6. Origin roller bolts 2 are provided on the upper support member 3 and the lower support member 4 for positioning the origin of the device's support structure. One side of the upper support member 3 is connected to the same side of the lower support member 4 via a rotating shaft, and the internal contours of both members are consistent with the outer contour of the base 6. The fastening bolts 5 are located on the non-connecting sides of the upper support member 3 and the lower support member 4.

[0023] In conjunction with the above-described device structure, the present invention also provides a low-temperature TIG welding method for a thin-walled substrate and an end plug, the method comprising the following steps:

[0024] Step 1: Cleaning the workpiece before welding. All components must be cleaned with an organic solvent before welding, followed by drying. Cleaning with an organic solvent before welding ensures the cleanliness of the weld. Acetone is preferred as the organic solvent, and the cleaning method is ultrasonic immersion in acetone. If the size of the workpiece to be welded is too large for ultrasonic immersion in acetone, a lint-free cloth soaked in acetone is used to wipe the welding area. The end plug 8 is cleaned by ultrasonic immersion in acetone, at least twice, with fresh acetone used for each immersion, and each immersion time is greater than or equal to 10 minutes. After immersion, the drying temperature is 80℃, and the drying time is greater than or equal to 20 minutes. For the end plug welding hole 7 on the substrate 6, a lint-free cloth soaked in acetone is used for wiping, followed by drying with a hair dryer.

[0025] Step 2: Assemble the base 6. Open the upper support 3 of the clamping device, place the base 6 horizontally on the lower support 4, then close the upper support 3 and lock it with the fastening bolts 5 to prevent the base 6 from moving during the welding process.

[0026] Step 3: Assembly of End Plug 8. Slowly insert End Plug 8 into the End Plug Welding Hole 7 on the Base 6, ensuring a planar fit between the end face of End Plug 8 and the end face of Base 6. Avoid inserting the end plug too deeply or too shallowly, which would result in a stepped fit between End Plug 8 and the end face of Base 6. The direction of End Plug 8 entering the End Plug Welding Hole 7 on Base 6 is such that the upper end face of the left side of End Plug 8 is inside the End Plug Welding Hole 7, and the lower end face of the right side of End Plug 8 achieves a planar fit with the end face of Base 6.

[0027] Step four, welding: After assembly, pulse welding is performed on the end plug 8 and the base 6. The welding mode can be either precision pulse or continuous pulse. The welding current is 100-300A, and the welding time is 1-20 seconds. After turning on the inert gas shielding gas, spot weld around the weld seam with the welding torch to complete the welding. After cooling for more than 10 minutes, the inert gas shielding gas is then turned off. The inert gas shielding gas is helium.

[0028] Example 1:

[0029] Step 1: Cleaning the workpieces for welding. To ensure the cleanliness of the weld, the parts need to be ultrasonically cleaned with acetone or the welding area needs to be wiped with a lint-free cloth dampened with acetone before welding. The end plug 8 is ultrasonically cleaned with acetone twice, with fresh acetone used each time. Each cleaning time is greater than or equal to 10 minutes, followed by drying. The drying temperature is 80℃, and the drying time is greater than or equal to 20 minutes. The welding holes 7 of the end plugs on the substrate 6 are wiped with a lint-free cloth dampened with acetone, and then dried with a hair dryer.

[0030] Step 2: Assemble the base 6. Open the upper support 3 of the clamping device, place the base 6 horizontally on the lower support 4, close the upper support 3, and tighten the base with the fastening bolts 5 to prevent the base 6 from moving during the welding process.

[0031] Step 3: Assembly of end plug 8. Slowly insert end plug 8 into end plug welding hole 7 of base 6 so that end face of end plug 8 and end face of base 6 achieve planar fit, avoiding insertion of end plug 8 too deep or too shallow.

[0032] Step 4: Select the welding mode as precision pulse mode, adjust the welding current to 250A, the welding time to 10s, turn on the helium shielding gas, and use the welding torch to spot weld around the weld seam to complete the welding.

[0033] Step 5: Wait for the workpiece to cool for 15 minutes, then turn off the helium protective gas. Inspect the appearance and penetration depth of the sample. The weld surface should achieve a welding effect that does not protrude from the base material surface, and the weld penetration depth should be greater than 0.4 mm.

[0034] Example 2:

[0035] Step 1: Cleaning the workpieces for welding. To ensure the cleanliness of the weld, the parts need to be ultrasonically cleaned with acetone or the welding area needs to be wiped with a lint-free cloth dampened with acetone before welding. The end plug 8 is ultrasonically cleaned with acetone twice, with fresh acetone used each time. Each cleaning time is greater than or equal to 10 minutes, followed by drying. The drying temperature is 80℃, and the drying time is greater than or equal to 20 minutes. The welding holes 7 of the end plugs on the substrate 6 are wiped with a lint-free cloth dampened with acetone, and then dried with a hair dryer.

[0036] Step 2, assembling the base 6. Open the upper support 3 of the clamping device, place the base 6 horizontally on the lower support 4, close the upper support 3, and tighten the base 6 with the fastening bolts 5 to prevent the base 6 from moving during the welding process.

[0037] Step 3: Assembly of end plug 8. Slowly insert end plug 8 into end plug welding hole 7 of base 6 so that end face of end plug 8 and end face of base 6 achieve planar fit, avoiding insertion of end plug 8 too deep or too shallow.

[0038] Step 4: Select the welding mode as continuous pulse mode, adjust the welding current to 150A, the welding time to 7s, turn on the helium shielding gas, and use the welding torch to spot weld around the weld seam to complete the welding.

[0039] Step 5: Wait for the workpiece to cool down for 15 minutes, then turn off the helium protective gas.

[0040] It should be noted that the combination of the technical features in the embodiments of the present invention is not limited to the combination methods described in the embodiments of the present invention or the combination methods described in the specific embodiments. All technical features described in the present invention can be freely combined or combined in any way, unless there is a contradiction between them.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-temperature TIG welding clamping device for a thin-walled substrate and an end plug, characterized in that, The device includes: a lower support member (4) set on a fixed base (1), on which the base (6) can be placed horizontally and provided support; an upper support member (3) is rotatably connected to the lower support member (4) and has opening and closing and rotation functions; both are consistent with the outer contour dimensions of the base (6) and are locked by fastening bolts (5), so as to realize the assembly, clamping and fastening of the base (6).

2. The low-temperature TIG welding clamping device for a thin-walled substrate and an end plug according to claim 1, characterized in that, Origin roller bolts (2) are provided on the upper support member (3) and the lower support member (4) for positioning the origin of the device support structure.

3. The low-temperature TIG welding clamping device for a thin-walled substrate and an end plug according to claim 1, characterized in that, One side of the upper support member (3) is connected to the same side of the lower support member (4) via a pivot, and the internal contours of the two are consistent with the outer contour of the base (6).

4. A low-temperature TIG welding clamping device for a thin-walled substrate and an end plug according to claim 1 or 3, characterized in that, The fastening bolts (5) are located on the non-connecting side of the upper support (3) and the lower support (4).

5. A low-temperature TIG welding method for a thin-walled substrate and an end plug, characterized in that, The method includes the following steps: Step 1: Cleaning the workpieces before welding. Before welding, each part needs to be cleaned with organic solvent and then dried. Step 2, assembling the base (6): open the upper support (3) of the clamping device, place the base (6) horizontally on the lower support (4), then close the upper support (3) and lock it with the fastening bolt (5); Step 3, end plug (8) assembly: slowly insert the end plug (8) into the end plug welding hole (7) on the base (6) so that the end face of the end plug (8) and the end face of the base (6) achieve planar fit; Step 4, welding. After the assembly is completed, pulse welding is performed on the end plug (8) and the base (6). The welding current is 100-300A and the welding time is 1-20s. After turning on the inert gas shielding gas, spot weld around the weld seam with the welding gun to complete the welding. After cooling for more than 10 minutes, turn off the inert gas shielding gas.

6. The low-temperature TIG welding method for a thin-walled substrate and an end plug according to claim 5, characterized in that, The preferred method for cleaning components with organic solvents before welding is ultrasonic immersion in acetone. If the size of the components to be welded does not allow for ultrasonic immersion in acetone, then a lint-free cloth soaked in acetone should be used to wipe the welding area.

7. The low-temperature TIG welding method for a thin-walled substrate and an end plug according to claim 5, characterized in that, The end plug (8) is cleaned by ultrasonic immersion in acetone, and the immersion is performed at least twice. New acetone is required for each immersion, and the immersion time is greater than or equal to 10 minutes.

8. The low-temperature TIG welding method for a thin-walled substrate and an end plug according to claim 7, characterized in that, The drying temperature of the end plug (8) after immersion and drying is 80°C, and the drying time is greater than or equal to 20 minutes.

9. A low-temperature TIG welding method for a thin-walled substrate and an end plug according to claim 1, characterized in that, The inert protective gas is helium.

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